| 1. |
- Bärring, Maja, 1988, et al.
(författare)
-
Factory Radio Design of a 5G Network in Offline Mode
- 2021
-
Ingår i: IEEE Access. - 2169-3536 .- 2169-3536. ; 9, s. 23095-23109
-
Tidskriftsartikel (refereegranskat)abstract
- The manufacturing industry is connecting people and equipment with new digital technologies, enabling a more continuous stream of data to represent processes. With more things connected, the interest in a connectivity solution that can support communication with high reliability and availability will increase. The fifth generation of telecommunication, i.e., 5G has promising features to deliver this, but the factory environment introduces new challenges to ensure reliable radio coverage. This will require efficient ways to plan the Factory Radio Design prior to installation. 3D laser scanning is used at an ever-increasing rate for capturing the spatial geometry in a virtual representation to perform layout planning of factories. This paper presents how to combine 3D laser scanning and physical optics (PO) for planning the Factory Radio Design of a cellular Long-Term Evolution (LTE) network (5G) in a virtual environment. 3D laser scanning is applied to obtain the spatial data of the factory and the virtual representation serves as the environment where PO computation techniques can be performed. The simulation result is validated in this paper by comparison to measurements of the installed network and empirical propagation models. The results of the study show promising opportunities to simulate the radio coverage in a virtual representation of a factory environment.
|
|
| 2. |
- Iupikov, Oleg, 1983, et al.
(författare)
-
A Cavity-Backed Patch Antenna with Distributed Multi-Port Feeding, Enabling Efficient Integration with Doherty Power Amplifier and Band-Pass Filter
- 2021
-
Ingår i: IEEE Transactions on Antennas and Propagation. - 0018-926X .- 1558-2221. ; 69:8, s. 4412-4422
-
Tidskriftsartikel (refereegranskat)abstract
- A joint design approach for co-integrated antenna and power amplifier (PA), employing a high-efficiency Doherty PA (DPA) architecture and including a band-pass RF filter, is proposed. This design is realized through the optimally distributed and balanced multi-port feeding of the cavity-backed patch antenna element that provides the desired (unique) loading conditions for the main and auxiliary PA branches and tailored power combining. A novelty and advantage of this feeding solution is that each pair of feeding points form a virtual common feeding centre of the radiating element; as a result, the radiation pattern remains power invariant when the port excitations change. A joint optimization of the integrated antenna-DPA transmitter is carried out to enhance the overall performance and maximize the bandwidth. This optimization is demonstrated through an example design for the sub-6 GHz telecommunication applications that target high power-efficiency (>50%) at the 6dB backed-off power levels and require RF-filtering in a compact integrated design. The latter challenge leads to a non-conventional implementation, which generally does not require the filter to be inserted between the antenna and the final output stage of the PA, and can be embedded in the topology with complex-valued source/load impedance values. Results of numerical studies are supported by measurements obtained with the antenna-DPA-filter prototype system.
|
|
| 3. |
- Zhu, Yuqing, 1998, et al.
(författare)
-
A Varactor-Based Reconfigurable Intelligent Surface Concept for 5G/6G mm-Wave Applications
- 2024
-
Ingår i: 18th European Conference on Antennas and Propagation, EuCAP 2024.
-
Konferensbidrag (refereegranskat)abstract
- A varactor-based reconfigurable intelligent surface (RIS) concept is presented for low-cost, high-precision beamforming of 5G/6G mm-waves. To enable this, we maximize the RIS unit cell (UC) phase coverage by (i) employing a varactor diode-tuned slotted-patch UC, and (ii) adding a metallic loop and via fence across the UC boundary, which also improves the bandwidth and angular insensitivity. In an infinite RIS environment, the UC exhibits a phase coverage of 330.7 degrees while maintaining the insensitivity of reflection coefficients up to 50-degree elevation angle. This UC design demonstrates a phase coverage that exceeds 315 degrees with under 0.7-dB reflection loss across a 11.6% bandwidth, where the capacitance tuning ratio of the considered commercial off-the-shelf varactor diode is only 1.8. A 15 × 15 RIS model with a 3-bit phase quantization is used for beam steering performance validation; it predicts the realized gain of 19.5 dBi for the 30-degree beam-steering direction at 28 GHz.
|
|
| 4. |
- Bressner, Thomas A.H., et al.
(författare)
-
Cell Partitioning Antenna System Performance in Multi-User Scenarios for mmWave Communications
- 2021
-
Ingår i: IEEE Access. - 2169-3536 .- 2169-3536. ; 9, s. 127141-127149
-
Tidskriftsartikel (refereegranskat)abstract
- Fixed-beam, high-gain antenna systems can be used for a finer partitioning of the currently used cell-sectoring. This partitioning has the benefit of reducing the number of users seen per antenna beam, which reduces interference. Furthermore, the high antenna gain allows for a high effective isotropic radiated power while keeping the transmit power low. In this paper, we study the performance of such a fixed-beam, high gain antenna system design for millimeter-wave mobile communications. The antenna system is designed to keep the inter-sector interference in a multi-site scenario low. The performance is analyzed for single- and multi-user environments. In single-input single-output mode, the 50th percentile of the signal-to-interference-plus-noise ratio lies between 12.5 dB to 39.7 dB if 3 to 0 interferers are present, respectively. For multiple-input multiple-output transmission using zero-forcing, the signal-to-interference-plus-noise ratio increases and the 50th percentile ranges from 36.1 dB to 43.3 dB if 3 to 0 interferes are present, respectively. By using maximum ratio transmission, the best performance is achieved with no interferers present, while a plunge in performance is observed with interferers. Furthermore, the study revealed that the narrow beam antenna system can also provide a clear signal separation for small spatial separations. In the given example, the signal-to-interference-plus-noise ratio is larger than 32.1 dB with 11 active antenna elements, where 2.8 meters separate the users. Hence, the paper shows that the cell-partitioning antenna systems provide coverage in the desired area while keeping the inter-sector interference low, and the considered transmission techniques can be used for situation optimized mobile communication links.
|
|
| 5. |
- Cappellin, C., et al.
(författare)
-
Design of a Push-Broom Multi-Beam Radiometer for Future Ocean Observations
- 2015
-
Ingår i: 9th European Conference on Antennas and Propagation, EuCAP 2015, Lisbon, Portugal, 13-17 May 2015. - 9788890701856
-
Konferensbidrag (refereegranskat)abstract
- The design of a push-broom multi-beam radiometer for future ocean observations is described. The radiometer provides a sensitivity one order of magnitude higher than a traditional conical scanning radiometer, and has the big advantage of being fully stationary relative to the satellite platform. Thanks to a dense focal plane array and a dedicated optimization procedure, the instrument can accurately measure in C, X and Ku band and as close as 15 km to the coast line.
|
|
| 6. |
- Cappellin, C., et al.
(författare)
-
Feed array breadboard for future passive microwave radiometer antennas
- 2018
-
Ingår i: IET Conference Publications. ; 2018:CP741
-
Konferensbidrag (refereegranskat)abstract
- The pattern of a 265 mm x 200 mm breadboard made of 35 x-polarized and 32 y-polarized Vivaldi antennas located above a finite ground plane is computed and measured at 6.9 GHz. The breadboard constitutes the feed array illuminating a 5 m conical scan antenna working at 6.9 GHz for next generation microwave radiometers for ocean observation. The analysis is done including mutual coupling between the elements, and in two commercial software, the MoM add-on to GRASP and CST. The breadboard is measured at the Spherical Near-Field Antenna Test Facility at the Technical University of Denmark.
|
|
| 7. |
- Cappellin, Cecilia, et al.
(författare)
-
Focal Plane Array Breadboard For Advanced Multiple Beam Radiometer Antennas
- 2017
-
Ingår i: 38th ESA Antenna Workshop on Innovative Antenna Systems and Technologies for Future Space Missions. ; , s. 1-8
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The detailed design and RF analysis of a breadboard made by 35 x-polarized and 32 y-polarized Vivaldi antennas, placed 0.67 wavelength from each other and located above a finite ground plane, are described. The breadboard constitutes a representative part of the feed array illuminating a conical scan or push-broom antenna for next generation microwave radiometers for ocean observation. The analysis are done at 6.9 GHz including mutual coupling between the elements, and in two commercial software, i.e. CST and the MoM add-on to GRASP.
|
|
| 8. |
- Cappellin, C., et al.
(författare)
-
Novel multi-beam radiometers for accurate ocean surveillance
- 2014
-
Ingår i: 8th European Conference on Antennas and Propagation, EuCAP 2014. - 9788890701849 ; , s. 3531-3535
-
Konferensbidrag (refereegranskat)abstract
- Novel antenna architectures for real aperture multi-beam radiometers providing high resolution and high sensitivity for accurate sea surface temperature (SST) and ocean vector wind (OVW) measurements are investigated. On the basis of the radiometer requirements set for future SST/OVW missions, conical scanners and push-broom antennas are compared. The comparison will cover reflector optics and focal plane array configuration.
|
|
| 9. |
- de lasson, Jakob R., et al.
(författare)
-
Innovative Multi-Feed-Per-Beam Reflector Antenna for Space-Borne Conical-Scan Radiometers
- 2018
-
Ingår i: 2018 IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM ON ANTENNAS AND PROPAGATION & USNC/URSI NATIONAL RADIO SCIENCE MEETING. - 1522-3965. - 9781538671023 - 9781538671023 ; , s. 1729-1730
-
Konferensbidrag (refereegranskat)abstract
- We present an antenna for use on conical-scan space-borne radiometers in C band and demonstrate that stringent radiometric requirements can be met. The antenna consists of a 5 m offset reflector fed by a focal plane array in a multi-feed-per-beam configuration, so far never used in ocean observation missions. We use distinct element beams and two optimization routines for obtaining element excitation amplitudes and phases, and with either routine, and in both x- and y-polarization, compliant beams, with footprint < 20 km, distance to coast < 20 km and accuracy < 0:25 K, are obtained. These results may pave the way for use of focal plane arrays with digital beamforming in future radiometric ocean observation missions.
|
|
| 10. |
- Elsakka, Amr, 1984, et al.
(författare)
-
A Design Concept of Power Efficient, High Gain Antenna System for mm-Waves Base Stations
- 2021
-
Ingår i: 2021 15TH EUROPEAN CONFERENCE ON ANTENNAS AND PROPAGATION (EUCAP). - 2164-3342.
-
Konferensbidrag (refereegranskat)abstract
- A design concept for a phased-array-fed reflector antenna system intended for millimeter-wave base stations is presented. This concept is motivated by the need for efficient beamforming antenna systems with reduced power consumption as compared to the presently considered fully-populated large-scale MIMO arrays. The main idea is to use a high-gain reflector antenna to maximize the effective isotropic radiated power. That in turn, allows minimizing the number of active antenna elements of the phased-array feed, and hence limit the total supplied power. The proposed reflector antenna system is based on a torus reflector which is illuminated by an offset phased-array feed. We show how to determine the antenna design parameters to achieve the desired cell coverage.
|
|
| 11. |
- Elsakka, Amr, et al.
(författare)
-
A mm-Wave Phased-Array Fed Torus Reflector Antenna with ±30° Scan Range for Massive-MIMO Base-Station Applications
- 2022
-
Ingår i: IEEE Transactions on Antennas and Propagation. - 0018-926X .- 1558-2221. ; 70:5, s. 3398-3410
-
Tidskriftsartikel (refereegranskat)abstract
- A phased-array fed reflector antenna system is presented which can be used for mm-wave base station applications. The proposed system is designed to support massive-Multi-Input-Multi-Output (MIMO) scenarios within a wide coverage (±30°) in the azimuth plane and a limited coverage at the elevation plane. A design and characterization methodology has been established to optimize the system for the operation in various line-of-sight conditions by adopting the maximum-ratio-transmission (MRT) and zero-forcing (ZF) MIMO algorithms. A two-user MIMO case study has been considered for the evaluation of the key system performance metrics, i.e. the effective isotropic radiated power, power consumption, signal-to-noise-ratio (SNR), and signal-to-interference-plus-noise-ratio (SINR). This study demonstrates that the phased-array fed reflector concept has a major advantage over traditional direct-radiating phased array (DRPA) antennas to reduce energy consumption. In the present example, it requires 12–14 dB less transmitted power as compared to the MRT-beamformed DRPAs for the same SNR, and 26–27 dB less transmitted power relatively to ZF-beamformed DRPA systems for the same SINR. A prototype, employing a 55 cm diameter torus reflector and operating at 28 GHz-band, has been manufactured and tested. The measurement results agree well with simulations.
|
|
| 12. |
- Glazunov, Andres Alayon, 1969, et al.
(författare)
-
Emulating Rician distributed channels in a hybrid chamber for OTA measurements
- 2021
-
Ingår i: 2020 International Symposium on Antennas and Propagation, ISAP 2020. ; , s. 549-550
-
Konferensbidrag (refereegranskat)abstract
- It has been shown by means of simulations that the rich isotropic multipath and the random line-of-sight channels and other Rician channels in-between can be successfully generated in the same over-the-air hybrid measurement chamber without the use of additional static or moving scatterers.
|
|
| 13. |
- Glazunov, Andres Alayon, 1969, et al.
(författare)
-
Multipath Rician Channel Simulation in the Test Zone of a Hybrid OTA Chamber
- 2021
-
Ingår i: 15th European Conference on Antennas and Propagation, EuCAP 2021.
-
Konferensbidrag (refereegranskat)abstract
- Multipath fields with ascribed Rician distribution parameters have been simulated in a novel hybrid chamber for over the air characterization of antenna systems and wireless devices. Simulations are based on waveguide mode summations representing a combination of the half-space rich isotropic multipath component and the on-axis line-of-sight component. It has been shown that the Rician distributed channels can be emulated without the use of additional static or moving scatterers.
|
|
| 14. |
- Iupikov, Oleg, 1983, et al.
(författare)
-
A Dual-Fed PIFA Antenna Element With Nonsymmetric Impedance Matrix for High-Efficiency Doherty Transmitters: Integrated Design and OTA-Characterization
- 2020
-
Ingår i: IEEE Transactions on Antennas and Propagation. - 0018-926X .- 1558-2221. ; 68:1, s. 21-32
-
Tidskriftsartikel (refereegranskat)abstract
- A single planar inverted F-antenna is proposed employing two input ports to optimally power-combine the output signals of two nonlinear power amplifiers inside the metal-only low-loss antenna structure. High power-added efficiency (PAE) at back-off power levels is reached through a Doherty combiner architecture, where the optimal power combination is seen to generally require the synthesis of a nonsymmetric antenna input impedance matrix. The dual-fed antenna is compact and exhibits close to single-mode radiation properties; it has a relatively stable gain pattern despite the nonequal Doherty power amplifier (PA) output powers. An integrated active prototype has been designed, fabricated, and characterized over-the-air in both an anechoic and a reverberation chamber. Good agreement is observed and an uncertainty analysis is performed. The Doherty transmitter features a max-PAE of 58 at 2.14 GHz and a 6 dB back-off PAE of 52; a minimum system power gain of 9.5 dB (max 12 dB); and a maximum system output power of 43.5 dBm.
|
|
| 15. |
- Iupikov, Oleg, 1983, et al.
(författare)
-
A Plane Wave Approximation in the Computation of Multiscattering Effects in Reflector Systems
- 2013
-
Ingår i: 7th European Conference on Antennas and Propagation, EuCAP 2013, Gothenburg, Sweden, 8-12 April 2013. - 2164-3342. - 9781467321877 ; , s. 3828-3832
-
Konferensbidrag (refereegranskat)abstract
- A hybrid MoM/PO method for the analysis of multiple scattering effects between reflector and large feeds, such as dense multibeam phased array feeds or multifrequency front-ends (MFFEs) in which higher frequency feeds operate in the vicinity of an extended metal structure, has been presented and studied. This paper evaluates the accuracy and computational efficiency for the MoM/PO method with and without using a uniform plane wave approximation of the reflector scattered field.
|
|
| 16. |
- Iupikov, Oleg, 1983, et al.
(författare)
-
An Optimal Beamforming Algorithm for Phased-Array Antennas Used in Multi-Beam Spaceborne Radiometers
- 2015
-
Ingår i: 9th European Conference on Antennas and Propagation, EuCAP 2015, Lisbon, Portugal, 13-17 May 2015. - 9788890701856
-
Konferensbidrag (refereegranskat)abstract
- Strict requirements for future spaceborne ocean missions using multi-beam radiometers call for new antenna technologies, such as digital beamforming phased arrays. In this paper, we present an optimal beamforming algorithm for phasedarray antenna systems designed to operate as focal plane arrays (FPA) in push-broom radiometers. This algorithm is formulated as an optimization procedure that maximizes the beam efficiency, while minimizing the side-lobe and cross- Polarization power inthe area of Earth, subject to a constraint on the beamformer dynamic range. The proposed algorithm is applied to a FPA feeding a torus reflector antenna (designed under the contract with the European Space Agency) and tested for multiple beams. The results demonstrate an improved performance in terms of the optimized beam characteristics, yielding much higher spatial and radiometric resolution as well as much closer distance to coast, as compared to the present-day systems.
|
|
| 17. |
- Iupikov, Oleg, 1983, et al.
(författare)
-
Dense focal plane arrays for pushbroom satellite radiometers
- 2014
-
Ingår i: 8th European Conference on Antennas and Propagation, EuCAP 2014; The Hague; Netherlands; 6 April 2014 through 11 April 2014. - 9788890701849 ; , s. 3536-3540
-
Konferensbidrag (refereegranskat)abstract
- Performance of a dense focal plane array feeding an offset toroidal reflector antenna system is studied and discussed in the context of a potential application in multi-beam radiometers for ocean surveillance. We present a preliminary design of the array feed for the 5-m diameter antenna at X-band. This array is optimized to realize high antenna beam efficiency (∼ 95%) over a wide scan range (±20°) with very low side-lobe and cross-polarization levels.
|
|
| 18. |
- Iupikov, Oleg, 1983, et al.
(författare)
-
Digital-beamforming array antenna technologies for future ocean-observing satellite missions
- 2016
-
Ingår i: 2016 IEEE Antennas and Propagation Society International Symposium, APSURSI 2016, Fajardo, Puerto Rico, 26 June - 1 July 2016. - 9781509028863 ; , s. 1377-1378
-
Konferensbidrag (refereegranskat)abstract
- Existing passive microwave radiometers that are used for ocean observations are limited in spatial resolution and geographic coverage, due to the limitations of traditional antenna technologies using mechanically-scanning reflectors and horn-type feeds. Future ocean observation missions call for new solutions, such as digitally-beamforming array feeds (DBAFs) as well as stationary and more complex reflectors. Our studies demonstrate that DBAFs can overcome the physically fundamental limitations of traditional horn feeds, and are capable of meeting all the challenging requirements for the next-generation instruments.
|
|
| 19. |
- Iupikov, Oleg, 1983
(författare)
-
Digital Beamforming Focal Plane Arrays for Radio Astronomy and Space-Borne Passive Remote Sensing
- 2017
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Dense Phased Array Feeds (PAFs) for reflector antennas have numerous advantages over traditional cluster feeds of horns in a one-horn-per-beam configuration, especially in RF-imaging applications which require multiple simultaneously formed and closely overlapping beams. However, the accurate analysis and design of such PAF systems represents a challenging problem, both from an EM-modeling and beamforming optimization point of view. The current work addresses some of these challenges and consists of two main parts.In the first part the mutual interaction effects that exist between a PAF consisting of many densely packed antenna elements and an electrically large reflector antenna are investigated. For that purpose the iterative CBFM-PO method has been developed. This method not only allows one to tackle this problem in a time-efficient and accurate manner, but also provides physical insight into the feed-reflector coupling mechanism and allows to quantify its effect on the antenna impedance and radiation characteristics. Numerous numerical examples of large reflector antennas with various representative feeds (e.g. a single dipole feed and complex PAFs of hundreds of elements) are also presented and some of them are validated experimentally. In order to analyze electrically large feeds efficiently, a domain-decomposition approach to Krylov subspace iteration, where macro basis functions (or characteristic basis functions) on each subdomain are naturally constructed from the different segments of the generating vectors, is also proposed.The second part of the thesis is devoted to the optimization of PAF beamformers and covers two application examples: (i) microwave satellite radiometers for accurate ocean surveillance; and (ii) radio telescopes for wide field-of-view sky surveys. Based on the initial requirements for future antenna systems, which are currently being formulated for these applications, we propose various figures-of-merits and describe the corresponding optimal beamforming algorithms that have been developed. Studies into these numerical examples demonstrate how optimal beamforming strategies can help to greatly improve the antenna system characteristics (e.g. beam efficiency, side-lobe level and sensitivity in the presence of the noise) as well as to reduce the complexity of the beam calibration models and overall phased array feed design.
|
|
| 20. |
- Iupikov, Oleg, 1983, et al.
(författare)
-
Domain-Decomposition Approach to Krylov Subspace Iteration
- 2016
-
Ingår i: IEEE Antennas and Wireless Propagation Letters. - : Institute of Electrical and Electronics Engineers (IEEE). - 1548-5757 .- 1536-1225. ; 15, s. 1414-1417
-
Tidskriftsartikel (refereegranskat)abstract
- Krylov subspace iterative techniques consist of finding the solution of a scattering problem as a linear combination of "generating vectors" obtained through successive matrix-vector multiplications. This letter extends this approach to domain-decomposition. Here, on each subdomain, a subspace is obtained by constructing the segments of each generating vector associated with the subdomain and by weighting these segments independently, which provides more degrees of freedom. The method is tested for scattering by a sphere and a rectangular plate, as well as radiation from connected arrays with strongly coupled antenna elements. It is shown that substantial computational savings can be obtained for the sphere and the array. This opens up new perspectives for faster solutions of multiscaled problems.
|
|
| 21. |
- Iupikov, Oleg, 1983, et al.
(författare)
-
Fast and Accurate Analysis of Reflector Antennas with Phased Array Feeds Including Multiple Reflections between Feed and Reflector
- 2014
-
Ingår i: IEEE Transactions on Antennas and Propagation. - 0018-926X .- 1558-2221. ; 62:7, s. 3450 - 3462
-
Tidskriftsartikel (refereegranskat)abstract
- Several electrically large phased array feed (PAF) reflector systems are modeled to examine the mechanism of multiple reflections between parabolic reflectors and low-and high-scattering feeds giving rise to frequency-dependent patterns and impedance ripples. The PAF current is expanded in physics-based macro domain basis functions (CBFs), while the reflector employs the physical optics (POs) equivalent current. The reflector-feed coupling is systematically accounted for through a multiscattering Jacobi approach. An FFT expands the reflector radiated field in only a few plane waves, and the reflector PO current is computed rapidly through a near-field interpolation technique. The FEKO software is used for several cross validations, and the convergence properties of the hybrid method are studied for several representative examples showing excellent numerical performance. The measured and simulated results for a 121-element Vivaldi PAF, which is installed on the Westerbork Synthesis Radio Telescope, are in very good agreement.
|
|
| 22. |
- Iupikov, Oleg, 1983, et al.
(författare)
-
Hybrid OTA Chamber for Multi-Directional Testing of Wireless Devices: Plane Wave Spectrum Generator Design and Experimental Demonstration
- 2022
-
Ingår i: IEEE Transactions on Antennas and Propagation. - 0018-926X .- 1558-2221. ; 70:11, s. 10974-10987
-
Tidskriftsartikel (refereegranskat)abstract
- This paper investigates practical implementation aspects of a novel hybrid chamber concept that has been recently introduced for over-the-air testing of wireless devices. The chamber allows to synthesize a spectrum of plane waves (PWs) incident on a device under test from a wide range of angles-of-arrival (AoAs) through exploiting multiple field scattering inside the overmoded waveguide chamber. An optimal design approach for the plane wave spectrum generator (PWSG) array inside the chamber is presented considering: (i) array antenna impedance matching for the desired test zone (TZ) quality and AoAs range; (ii) an operational frequency bandwidth of the test environment and an instantaneous signal bandwidth; and (iii) the impact of the PWSG excitation errors. A robust linearly constrained minimum variance (LCMV) beamformer is formulated to realize the desired test environment over a wide frequency band, while accounting for the varying number of the waveguide propagating modes as excited by the PWSG array. Numerical simulations and measurements with the first prototype of the hybrid chamber for FR1 frequency band (~3.5 GHz) are presented. This prototype includes a 7 × 7 bowtie antenna element PWSG array, a 1.00 × 1.25 × 1.75 m metal waveguide chamber, an off-line optimal array beamforming setup, and a planar scanner for the TZ characterization.
|
|
| 23. |
- Iupikov, Oleg, 1983, et al.
(författare)
-
Indoor Received Power Prediction Based on Physical Optics (PO): Simulations and Experimental Validation in Industrial Environment
- 2019
-
Ingår i: 13th European Conference on Antennas and Propagation, EuCAP 2019.
-
Konferensbidrag (refereegranskat)abstract
- This study presents an approach based on Physical Optics computations to predict the receive signal power in an indoor environment. The application in focus pertains the development of highly reliable manufacturing industry processes where wireless communications plays a key role. Our proposed numerical method shows a good agreement with measurement data. It is therefore suggested that Electromagnetic modelling based on computationally efficient Physical Optics algorithms can be used as a complement, an alternative or even a replacement for empirical models requiring time consuming measurement campaigns.
|
|
| 24. |
- Iupikov, Oleg, 1983, et al.
(författare)
-
Multi-Beam Focal Plane Arrays with Digital Beamforming for High Precision Space-Borne Remote Sensing
- 2017
-
Ingår i: IEEE Transactions on Antennas and Propagation. - 0018-926X .- 1558-2221.
-
Tidskriftsartikel (refereegranskat)abstract
- The present-day ocean remote sensing instruments that operate at low microwave frequencies are limited in spatial resolution and do not allow for monitoring of the coastal waters.This is due the difficulties of employing a large reflector antenna on a satellite platform, and generating high-quality pencil beams at multiple frequencies. Recent advances in digital beamforming focal-plane-arrays (FPAs) have been exploited in the current work to overcome the above problems. A holistic design procedure for such novel multi-beam radiometers has been developed, where (i) the antenna system specifications are derived directly from the requirements to oceanographic surveys for future satellite missions; and (ii) the numbers of FPA elements/receivers are determined through a dedicated optimum beamforming procedure minimizing the distance to coast.This approach has been applied to synthesize FPAs for two alternative radiometer systems: a conical scanner with an off-set parabolic reflector, and stationary wide-scan torus reflector system; each operating at C, X and Ku bands. Numerical results predict excellent beam performance for both systems with as low as 0.14% total received power over the land.
|
|
| 25. |
- Iupikov, Oleg, 1983, et al.
(författare)
-
Multibeam Focal Plane Arrays with Digital Beamforming for High Precision Space-Borne Ocean Remote Sensing
- 2018
-
Ingår i: IEEE Transactions on Antennas and Propagation. - 0018-926X .- 1558-2221. ; 66:2, s. 737-748
-
Tidskriftsartikel (refereegranskat)abstract
- The present-day ocean remote sensing instruments that operate at low microwave frequencies are limited in spatial resolution and do not allow for monitoring of the coastal waters. This is due to the difficulties of employing a large reflector antenna on a satellite platform, and generating high-quality pencil beams at multiple frequencies. Recent advances in digital beamforming focal-plane arrays (FPAs) have been exploited in this paper to overcome the above problems. A holistic design procedure for such novel multibeam radiometers has been developed, where: 1) the antenna system specifications are derived directly from the requirements to oceanographic surveys for future satellite missions and 2) the numbers of FPA elements/receivers are determined through a dedicated optimum beamforming procedure minimizing the distance to coast. This approach has been applied to synthesize FPAs for two alternative radiometer systems: a conical scanner with an offset parabolic reflector and a stationary wide-scan torus reflector system, each operating at C -, X-, and Ku-bands. Numerical results predict excellent beam performance for both systems with as low as 0.14% total received power over the land.
|
|
| 26. |
- Iupikov, Oleg, 1983
(författare)
-
Phased-Array-Fed Reflector Antenna Systems for Radio Astronomy and Earth Observations
- 2014
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Dense Phased Array Feeds (PAFs) for reflector antennas have numerous advantages over traditional cluster feeds of horns in a one-horn-per-beam configuration, especially in RF-imaging applications which require multiple simultaneously formed and closely overlapped beams. However, the accurate analysis and design of such PAF systems represents a challenging problem, both from an EM-modeling and beamforming optimization point of view. The current work addresses some of these challenges and consists of two main parts. In the first part the mutual interaction effects that exist between a PAF consisting of many densely packed antenna elements and an electrically large reflector antenna are investigated. For that purpose the iterative CBFM-PO method has been developed. This method not only allows one to tackle this problem in a time-efficient and accurate manner, but also provides physical insight into the feed-reflector coupling mechanism and allows to quantify its effect on the antenna impedance and radiation characteristics. Numerous numerical examples of large reflector antennas with various representative feeds (e.g. a single dipole feed and complex PAFs of hundreds of elements) are also presented and some of them are validated experimentally. The second part of the thesis is devoted to the optimization of PAF beamformers and covers two application examples: (i) microwave satellite radiometers for accurate ocean surveillance; and (ii) radio telescopes for wide field-of-view sky surveys. Based on the initial requirements for future antenna systems, which are currently being formulated for these applications, we propose various figures-of-merit and describe the corresponding optimal beamforming algorithms that have been developed. Studies into these numerical examples demonstrate how optimal beamforming strategies can help to greatly improve the antenna system characteristics (e.g. beam efficiency, side-lobe level and sensitivity in the presence of the noise) as well as to reduce the complexity of the beam calibration models and overall phased array feed design.
|
|
| 27. |
- Iupikov, Oleg, 1983, et al.
(författare)
-
Prediction of Far-Field Pattern Characteristics of Phased Array Fed Reflector Antennas by Modeling Only a Small Part of the Array - Case Study of Spaceborne Radiometer Antennas
- 2017
-
Ingår i: Proceedings of the 11th European Conference on Antennas and Propagation, EUCAP 2017, Paris, France, April 2017. - 2164-3342. - 9788890701870 ; , s. 2636-2639.
-
Konferensbidrag (refereegranskat)abstract
- In this work we present an approach for the prediction of far-field pattern characteristics of phased array fed reflector antennas by modeling only a small part of the array. In this approach, the simulated EEPs of the FPA are modeled as the phase-shifted versions of the simulated embedded element pattern (EEP) of the central element, and thereafter combined with the optimum weighting coefficients in order to find the total pattern of the feed. Although, the EEPs of dense array antennas are generally not identical (due to the array antenna mutual coupling and edge truncation effects), for typical FPA excitation scenarios, where the array edge elements have relatively low weights to produce the desired illumination of the reflector, this simplified approach has been found sufficiently accurate.
|
|
| 28. |
- Iupikov, Oleg, 1983, et al.
(författare)
-
Reconfigurable Intelligent Surfaces for OTA Testing: Optimization and Initial Results
- 2023
-
Ingår i: IEEE Conference on Antenna Measurements and Applications, CAMA. - 2474-1760. ; , s. 846-851
-
Konferensbidrag (refereegranskat)abstract
- We discuss a new application of RIS for Over-The-Air (OTA) testing of antenna systems and wireless devices, particularly as a cost-effective alternative to millimeter-wave phased-array plane wave generators (PWGs). We present a general approach for the fast modeling and design of the RIS-based PWG. This includes an optimal beamforming algorithm for a RIS and a strategy for configuring the RIS unit cells (UCs) to emulate far-field conditions in the test zone (TZ) with a controllable angle of arrival (AoA) of the incoming plane wave. The proposed approach has been used to derive requirements for a UC of the 21x21 element RIS-based PWG. Our preliminary numerical results demonstrate that the RIS-based PWG allows for synthesizing a TZ with a high-quality plane wave spectrum, where the peak-to-peak variation in field magnitude remains below 0.7 dB, while phase fluctuations do not exceed 5 deg within the range of AoA from -7 deg to 7 deg.
|
|
| 29. |
- Iupikov, Oleg, 1983, et al.
(författare)
-
The Hybrid Chamber for OTA measurements: Plane Wave Spectrum Quality Vs. Dynamic Range Trade-off
- 2022
-
Ingår i: 2022 16th European Conference on Antennas and Propagation, EuCAP 2022.
-
Konferensbidrag (refereegranskat)abstract
- In this paper, the trade-off between the quality of the plane wave spectrum synthesized in the test zone of the hybrid over-the-air (OTA) chamber and factors affecting the dynamic range of this measurement system is investigated. The hybrid chamber performance is compared to a plane wave generator (PWG) in free space. The performance evaluation is focused on the field radiated into the test zone (TZ) while maintaining its quality according to 3GPP specification. It is demonstrated that a good quality can be achieved for the synthesized plane wave spectrum.
|
|
| 30. |
- Iupikov, Oleg, 1983, et al.
(författare)
-
Towards the understanding of the interaction effects between reflector antennas and phased array feeds
- 2012
-
Ingår i: 2012 International Conference on Electromagnetics in Advanced Applications (ICEAA), Cape Town, WP, South Africa, 2-8 Sept 2012. - 9781467303354 ; , s. 792-795
-
Konferensbidrag (refereegranskat)abstract
- A computationally efficient numerical procedure has been developed and used to analyze the mutual interaction effects between an electrically large reflector antenna and a phased array feed (PAF). The complex electromagnetic behavior for such PAF systems is studied through a few simple and didactical examples, among which a single dipole antenna feed, a singly-excited antenna in an array of 20 dipoles, and a fully-excited array. These examples account for the effects of the ground plane, active loading (low noise amplifiers), and beamforming scenario, and are used to illustrate the differences between single-port feeds and PAFs.
|
|
| 31. |
- Ivashina, Marianna, 1975, et al.
(författare)
-
An axi-symmetric segmented composite SKA dish design: Performance and production analysis
- 2011
-
Ingår i: Asia-Pacific Microwave Conference, APMC 2011; Melbourne, VIC; 5 - 8 December 2011. - 9780858259744 ; , s. 1182-1185
-
Konferensbidrag (refereegranskat)abstract
- A concept of an axi-symmetric dish as antenna reflector for the next generation radio telescope - the Square Kilometre Array (SKA) - is presented. The reflector is based on the use of novel thermoplastic composite material (reinforced with carbon fibre) in the context of the telescope design with wide band single pixel feeds. The baseline of this design represents an array of 100's to 1000's reflector antennas of 15-m diameter and covers frequencies from
|
|
| 32. |
- Ivashina, Marianna, 1975, et al.
(författare)
-
Design of Wideband Quadruple-Ridged Flared Horn Feeds for Future Radio Telescopes
- 2014
-
Ingår i: Swedish Microwave Days March 11-12, 2014, Gothenburg, Sweden.
-
Konferensbidrag (refereegranskat)abstract
- Balanced excitations are required to achieve ultra wideband performance with the novel reflector antenna feeds consisting of pair(s) of interleaved spiral, log-periodical or other travelling-wave structures, which are currently being developed for radio astronomic instruments [1]–[3]. This excitation is commonly realized by using a balun interfacing the balanced antenna to single-ended amplifiers. However, practical designs of such passive networks are often bulky and lead to power dissipation losses. Power dissipation reduces the antenna radiation efficiency and increases the system thermal noise temperature. Another limiting factor is that the ultra wideband balun design restricts the reference impedance for the optimum noise matching between the antennas and low-noise amplifiers (LNAs). To obviate these disadvantages, differential low-noise amplifiers (dLNA), which can be directly integrated at the antenna terminals, represent an interesting alternative solution.
|
|
| 33. |
- Ivashina, Marianna, 1975, et al.
(författare)
-
Optimization of the 0.35-1.05 GHz Quad-Ridged Flared Horn and Eleven feeds for the Square Kilometer Array baseline design
- 2014
-
Ingår i: Proceedings - 2014 International Conference on Electromagnetics in Advanced Applications, ICEAA 2014. - 9781467357104 ; , s. 513-516
-
Konferensbidrag (refereegranskat)abstract
- Initial optimization results for the wide-band Eleven antenna and Quadruple-Ridged Flared Horn (QRFH), designed to operate as the reflector antenna feeds at 350 - 1050 MHz, are presented and discussed in the context of the next generation radio telescope - the Square Kilometer Array (SKA). First, we describe the procedure that has been developed to carry out time-efficient optimization of the feeds for multiple antenna optics configurations at the system level (so as to maximize the antenna-receiver sensitivity), and then cross-compare the two feed types by assessing the main antenna system characteristics and radio-astronomy performance metrics.
|
|
| 34. |
- Krasov, Pavlo, 1981, et al.
(författare)
-
Characterization and Calibration of the Hybrid OTA Chamber Using a Field Scanner
- 2022
-
Ingår i: 2022 16th European Conference on Antennas and Propagation, EuCAP 2022.
-
Konferensbidrag (refereegranskat)abstract
- This paper investigates the characterization and calibration procedure of the hybrid over-the-air (OTA) measurement chamber. We present a prototype of the hybrid chamber and analyze its capabilities to generate a plane wave spectrum in practice. A planar field scanner is used to acquire the embedded element fields of the chamber array for test zone (TZ) synthesis in post-processing. The repeatability of the field acquisition is evaluated. It is shown that the synthesized TZ meets the 3GPP specifications for TZ field variations for plane wave generators (PWG) in the presence of acquisition imperfections.
|
|
| 35. |
- Krasov, Pavlo, 1981, et al.
(författare)
-
Optimization of the TRP evaluation in Anechoic-Reverberation Hybrid Chamber
- 2024
-
Ingår i: 18th European Conference on Antennas and Propagation, EuCAP 2024.
-
Konferensbidrag (refereegranskat)abstract
- A hybrid, reconfigurable anechoic-reverberation antenna measurement chamber has recently been introduced. The chamber is developed for fast characterization of the active antenna radiated power and directive characteristics in a single measurement environment. In the present work, we propose optimizations of the hybrid chamber design in the configuration that uses E-field scanner. Introducing the wedge reflector in the chamber allows for a reduction in the total number of acquisition samples four times compared to λ/2 spaced scan during the total radiated power (TRP) measurements.
|
|
| 36. |
- Krasov, Pavlo, 1981, et al.
(författare)
-
Quiet Zone Quality of a Plane Wave Generator inside an Over-Moded Waveguide Chamber Emulating a Variable Angle of Incidence
- 2021
-
Ingår i: 15th European Conference on Antennas and Propagation, EuCAP 2021.
-
Konferensbidrag (refereegranskat)abstract
- We investigate the use of a hybrid over-the-air (OTA) measurement chamber to emulate far-field testing conditions. The focus has been on the generation of a plane wave arriving at an arbitrary angle-of-arrival (AoA) to the device-under-test (DUT) without mechanical steering. The chamber consists of an oversized waveguide (WG) and a planar array antenna with adaptive beamforming. A modified linear constrained minimum variance (LCMV) beamforming algorithm is used to form a quiet zone (QZ) in the DUT region by using the reflections from the WG's metal walls. The LCMV beamformer formulation has been extended to achieve a volumetric QZ with the desired amplitude and phase uniformity. Numerical studies for the QZ size corresponding to an FR1 base station demonstrate promising results with the low levels of amplitude and phase variation. The AoA coverage of this chamber meets 3GPP specification requirements for OTA conformance testing of base stations with active antenna systems.
|
|
| 37. |
- Krasov, Pavlo, 1981, et al.
(författare)
-
Reconfiguration Capabilities of the Anechoic-Reverberation Hybrid Chamber for TRP Measurements of Active Antenna Systems
- 2023
-
Ingår i: 17th European Conference on Antennas and Propagation, EuCAP 2023.
-
Konferensbidrag (refereegranskat)abstract
- A hybrid, reconfigurable anechoic-reverberation antenna measurement chamber was recently introduced with the vision to enable fast characterization of the active antenna radiated power and directive characteristics in a single measurement environment. The initial studies included its design and analysis in the plane wave spectrum generator scenario. In the present work, we investigate chamber reconfiguration capabilities for performing total radiated power (TRP) measurements. We show how different types of interchangeable hybrid chamber modules allow realizing several possible ways of measuring TRP. Trade-offs in terms of measurement time and implementation complexity are discussed. Finally, one of the methods, using a chamber array antenna module, is selected and demonstrated in simulations. Our initial results indicate TRP measurement error within ±0.5 dB.
|
|
| 38. |
- Kruglov, Dmitrii, 1994, et al.
(författare)
-
Contactless Measurement of a D-Band On-Chip Antenna Using an Integrated Reflective Load Switch
- 2024
-
Ingår i: IEEE Antennas and Wireless Propagation Letters. - 1548-5757 .- 1536-1225. ; 23:3, s. 1075-1079
-
Tidskriftsartikel (refereegranskat)abstract
- A novel measurement setup is proposed for the contactless characterization of on-chip antennas. A D-band patch antenna is fabricated on a 100 μm-thick GaAs substrate and is monolithically integrated with a reflective load switch to allow for fast electronic control of the antenna port termination. The antenna under test is illuminated by a reference antenna in the anechoic chamber after which the impedance and gain of the patch antenna are reconstructed from the change in backscattered field due to different port terminations. In our experiment, the over-the-air reconstructed antenna input impedance exhibits a frequency shift of less than 1% with respect to the (non-ideal) on-wafer probe measurement in the 115–130 GHz frequency range. Furthermore, the measured realized gain of 0.9±0.5 dBi is close to the simulated one of 1.1 dBi.
|
|
| 39. |
- Kruglov, Dmitrii, 1994, et al.
(författare)
-
Enhancing mmWave On-Chip-Antennas Using In-Package Electromagnetic Bandgap Structures
- 2021
-
Ingår i: European Microwave Conference. - 1527-3342 .- 1557-9581. - 9782874870637 ; , s. 885-888
-
Konferensbidrag (refereegranskat)abstract
- We propose a silicon on-Chip-in-Package antenna design featuring a simulated radiation efficiency of > 70% and an S11 matching better than −10 dB in the 112–125 GHz frequency range. High radiation performance is achieved by: (i) thinning the silicon substrate down to 100 μm through wafer-level grinding; (ii) embedding the IC in-between two PCBs, one of which forms an electromagnetic bandgap structure that attenuates the EM leakage inside the silicon substrate. Furthermore, since the die-embedding concept employs the gap-waveguide packaging technology, a universal contactless waveguide interconnect is realized between the IC and the radiating gap waveguide in the package. This will also enable modular antenna designs.
|
|
| 40. |
- Kruglov, Dmitrii, 1994, et al.
(författare)
-
Numerical analysis of Huygens-like on-chip antennas for mm-wave applications
- 2021
-
Ingår i: 15th European Conference on Antennas and Propagation, EuCAP 2021.
-
Konferensbidrag (refereegranskat)abstract
- As we transition to 5G and beyond, the frequencies increase and the efficiency of the antennas becomes a pressing issue. Silicon technologies are preferred when it comes to en masse user equipment production, but the antennas in silicon suffer from high dielectric losses and strong substrate waves coupling. The use of a Huygens source as the antenna element has a potential of decreasing these negative effects, as was demonstrated in several non-silicon PCB designs. In this paper, we investigate if a similar performance enhancement can be achieved in thin back-gated silicon antenna chips. We present a numerical comparison of an electric dipole, a magnetic dipole and a Huygens source antenna at 120 GHz on a lossy silicon substrate sitting on a ground plane. Antennas are defined in MATLAB as distributed currents and imported as near-field sources into CST Microwave Studio. This way we treat the problem in a very general way without regards for any particular physical antenna implementations. Radiation efficiency and gain are shown as functions of substrate thickness. We found that there is no apparent advantage of using a Huygens source over either electric or a magnetic dipole in the described setup. We argue that this result is based on the fact that the Huygens source is derived assuming infinite current sheets at the interface of two infinite homogeneous regions, and propose another definition for a Huygens source in multi-layer structures.
|
|
| 41. |
- Liao, Wan-Chun, 1985, et al.
(författare)
-
A Directly Matched PA-Integrated K-band Antenna for Efficient mm-Wave High-Power Generation
- 2019
-
Ingår i: IEEE Antennas and Wireless Propagation Letters. - 1548-5757 .- 1536-1225. ; 18:11, s. 2389-2393
-
Tidskriftsartikel (refereegranskat)abstract
- A K-band slot antenna element with integrated GaN (Gallium nitride) power amplifier (PA) is presented. It has been optimized through a circuit-EM co-design methodology to directly match the transistor drain output to its optimal load impedance ( Zopt=17+j46Ω ) while accounting for the over-the-air coupling effects in the vicinity of the transition between the PA and antenna. This obviates the need for using a potentially lossy and bandwidth-limiting output impedance matching network. The measured PA-integrated antenna gain of 15 dBi with a 40% total efficiency at 28 dBm output power agrees well with the theoretically achievable performance targets. The proposed element is compact ( 0.6×0.5×0.3 λ3 ), and thus well-suited to meet the high-performance demands of future emerging beamforming active antenna array applications.
|
|
| 42. |
- Maaskant, Rob, 1978, et al.
(författare)
-
A New Hybrid Chamber for Generating a Spectrum of Oblique Incident Plane Waves at the DUT
- 2021
-
Ingår i: IEEE Transactions on Antennas and Propagation. - 0018-926X .- 1558-2221. ; 69:10, s. 6806-6815
-
Tidskriftsartikel (refereegranskat)abstract
- A novel type of hybrid measurement facility comprising a chamber antenna array (CAA) inside an overmoded waveguide is proposed and analyzed numerically. The reflecting walls of the metal rectangular waveguide (WG) are used in conjunction with a CAA to synthesize obliquely incident plane wave (PW) fields at the device under test (DUT). This enables increased flexibility in emulating almost any PW multipath testing conditions in the WG chamber without the high cost and complexity of classical anechoic measurement systems employing relatively large phase-steered plane wave generators. A modeling framework is proposed that has been used to devise first-order design rules (e.g. the number of independent propagating modes, dimensions of the WG, CAA, and DUT). Afterwards, an optimally beamformed CAA example is presented to numerically validate the quality of the on- and off-axis plane wave fields in the test zone. This study shows design trade-offs between the amplitude ripple in the DUT region, the total power focused in this region, the DUT size and the angle of incidence.
|
|
| 43. |
- Maaskant, Rob, 1978, et al.
(författare)
-
Analysis of large microstrip-fed tapered slot antenna arrays by combining electrodynamic and quasi-static field models
- 2011
-
Ingår i: IEEE Transactions on Antennas and Propagation. - 0018-926X .- 1558-2221. ; 59:6, s. 1798-1807
-
Tidskriftsartikel (refereegranskat)abstract
- A reduced-order model for large arrays of microstrip-fed tapered slot antennas (TSAs) is presented. The currents on the antenna conductors are modeled by a relatively small number of physics-based macro-domain basis functions through a technique which is known as the characteristic basis function method (CBFM). The array is treated as a metal-only structure, while the wideband microstrip feeds are separately modeled using quasi-static circuit models. It is demonstrated that, even though the dielectric-supported feeds are non-shielded and therefore form an integral part of each radiating antenna element, the feeds can be modeled independently from the strongly coupled antenna elements. Validation of the combined antenna-feed model has been carried out through the measurements of several practically realized TSA arrays, among them a 8 × 7 × 2 dual-polarized array. The results demonstrate good agreement over a large scan range, as well as over a wide frequency band. The polarization-discrimination capabilities of the antenna, when operating in phased-array mode, have been analyzed in the context of radio-astronomical applications.
|
|
| 44. |
- Maaskant, Rob, 1978, et al.
(författare)
-
Deep Integration Antenna Array: Design Philosophy and Principles
- 2019
-
Ingår i: 13th European Conference on Antennas and Propagation, EuCAP 2019.
-
Konferensbidrag (refereegranskat)abstract
- An active integrated antenna array is designed through a new design low called Deep Integration. Amplifier output currents are combined to synthesize the optimal antenna current distribution to produce the desired radiation characteristics. The electromagnetic field from a cluster of amplifiers is power-combined in low-loss (air) dielectrics inside a single antenna element to increase the total radiated output power. These elements can be combined in an array to further increase radiated power. Such solutions are highly compact in size and capable of delivering high Effective Radiated Power (ERP), which is particularly important in the area of mm-wave integrated circuit design for wireless applications. A simulation example is provided of a Deep Integration antenna array, demonstrating the design philosophy and principles.
|
|
| 45. |
|
|
| 46. |
|
|
| 47. |
- Skou, N., et al.
(författare)
-
Ultra-High-Performance C-and L-Band Radiometer System for Future Spaceborne Ocean Missions
- 2019
-
Ingår i: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing. - 2151-1535 .- 1939-1404. ; 12:6, s. 1670-1678
-
Tidskriftsartikel (refereegranskat)abstract
- A next-generation real-Aperture spaceborne radiometer system for high-quality ocean measurements is discussed. Instead of illuminating the antenna reflector by a classical feed array of horn antennas in a one-feed-per-beam configuration, a multi-feed-per-beam configuration is chosen. Each antenna beam is thus created by adding the outputs from many small antenna elements in the feed array, thus providing an antenna beam of unsurpassed quality. This solves the classical polarization purity and land/sea contamination issues. The concept requires many microwave receivers and fast analog-To-digital converters as well as fast digital signal processing onboard the satellite. This is discussed, and resource budgets, especially concerning power, are provided.
|
|
| 48. |
- Skou, N., et al.
(författare)
-
Ultra-high performance C L-band radiometer system for future spaceborne ocean missions
- 2018
-
Ingår i: 15th Specialist Meeting on Microwave Radiometry and Remote Sensing of the Environment, MicroRad 2018 - Proceedings. ; , s. 42-47
-
Konferensbidrag (refereegranskat)abstract
- A next generation spaceborne radiometer system for hi-quality ocean measurements is discussed. Instead of a classical horn, a focal plane array is used as antenna feed. The antenna beam is created by adding the outputs from many small antenna elements, thus providing an antenna beam of unsurpassed quality. This solves the classical polarization purity and land/sea contamination issues. The concept requires many microwave receivers and fast analog-to-digital converters as well as fast digital signal processing on-board the satellite. This is discussed, and resource budgets, especially concerning power, are provided.
|
|
| 49. |
- Van't Klooster, C., et al.
(författare)
-
On Antenna-Architectures for Sensitive Radiometry to Support Oceanography
- 2015
-
Ingår i: 40th COSPAR Scientific Assembly.
-
Konferensbidrag (refereegranskat)abstract
- The presentation discusses different antenna architectures supporting radiometric tasks for oceanographic observations. With Aquarius and SMOS in orbit with their associated resolution and revisit capability in L-band, further enhancements are of interest. Following studies into desirable resolution and frequency band interests for oceanographic applications (ref: Microwat - an ESA study, see also https://www.ghrsst.org/ ), breaking through and desirable requirements have been derived. Investigations into potential antenna architectural realisations have been initiated. Included are radiometer sensor (read:antenna) scenarios, based on conical scanning, interferometric 1D and pushbroom coverage. A wide coverage is available from the first two architectures, and a very good sensitivity is available with the pushbroom scenario. There are a couple of interesting aspects, related to polarimetry capabilities, resolution, sensitivity, etc. The pushbroom architecture, at cost of some complexity offers a very good sensitivity with interesting antenna architecture solutions to offer breaking through capabilities, in particular concerning the sensitivity requirements, in combination with polarimetric capabilities. Coverage comes with some infrastructural antenna complexity, with the needs and creativity for a deployable antenna configuration. Following initial considerations for all three antenna configurations at overview level, the push-broom scenario is presented with more details. Interesting aspects include ongoing technology developments in other related fields with refined results to come would enable to consider antenna architectures are used in which focal plane arrays find a combination with shaped reflector assemblies. With processing capabilities further enhanced - with ongoing developments underway in other sectors as radio astronomers can confirm - one would be able to further improve and refine sensitivity aspects in combination with polarimetric capabilities and resolution enhancement. Instrument sensors (read: antennas) have to be absolutely accurate, where in comparison telecommunication scenarios require a link budget to be fulfilled. The developments and availability of RF front-end and Analogue to Digital circuitry are an important aspect here, enabling the use of focal plane arrays with several hundreds of elements, as already ongoing within the radio-astronomy studies for the square kilometer arrays. Terrestrial applications in low power circuitries are ongoing in various domains, be it for local networks, sensor networks or other (various, IMEC, Fraunhofer, etc.). Further spin-in is expected. One could consider the resulting microwave push-broom antenna architecture in fact as a sensitive multi-frequency microwave camera, operating in frequency bands of interest. We are investigating currently the pushbroom scenario for 2, possibly 3 bands, from C-band up to Ku-band.
|
|
| 50. |
- Vilenskiy, Artem, 1988, et al.
(författare)
-
Co-Design and Validation Approach for Beam-Steerable Phased Arrays of Active Antenna Elements with Integrated Power Amplifiers
- 2021
-
Ingår i: IEEE Transactions on Antennas and Propagation. - 0018-926X .- 1558-2221. ; 69:11, s. 7497-7507
-
Tidskriftsartikel (refereegranskat)abstract
- An approach for designing a beam-steering active phased array of antenna elements with integrated power amplifiers (PAs) is presented. It is based on an amplifying active integrated unit cell (AiUC) concept, where the AiUC comprises a radiating slot element, a GaN high electron mobility transistor (HEMT), its input matching and DC biasing/feeding circuitry. The HEMT is embedded in the antenna element, being directly impedance-matched to HEMT’s drain output, i.e. without using any intermediate and potentially lossy impedance matching network. The proposed co-design approach involves a full-wave analysis of the AiUC passive part (naturally including elements mutual coupling effects) along with the subsequent full system harmonic balance simulations. Furthermore, we extend the standard definition of the scan element pattern (SEP) to the active scan element pattern (ASEP) that accounts for nonlinear effects of PAs on AiUC performance. We show that the ASEP is, in general, power-dependent and has a different shape as compared to the SEP. The proposed approach has been demonstrated for a K-band AiUC design example. It was verified through an active waveguide simulator, which is equivalent to the 23.7° H-plane beam-steering case. Measurements are in good agreement with simulations, revealing AiUC 47% peak drain efficiency and 33 dBm maximum radiated power. The predicted scan range is ±60° and ±37° in the E- and H-plane, respectively.
|
|
