| 1. |
- Bencivenni, Carlo, 1986, et al.
(författare)
-
Effects of Regular and Aperiodic Array Layout in Multi-User MIMO Applications
- 2017
-
Ingår i: IEEE Antennas and Propagation Society International Symposium. - 1522-3965. - 9781538632840 ; 2017-January, s. 1877-1878
-
Konferensbidrag (refereegranskat)abstract
- In MIMO applications, antenna arrays adopt a uniform regular lattice. However, in phased array applications, it is a well-known fact that aperiodic or irregular arrays can offer several advantages. In this paper, we present initial investigations on the effects of regular and aperiodic layouts in Multi-User MIMO applications. We aim at explaining and providing an intuitive understanding on why aperiodic arrays are superior to regular ones. Additional results and quantification of the advantages will be presented in an upcoming journal publication.
|
|
| 2. |
- Botha, Matthys, 1976, et al.
(författare)
-
Results in quadrature error estimation for weak near-singular MoM integrals
- 2017
-
Ingår i: 2017 IEEE INTERNATIONAL SYMPOSIUM ON ANTENNAS AND PROPAGATION & USNC/URSI NATIONAL RADIO SCIENCE MEETING. - 1522-3965. - 9781538632840 ; , s. 1555-1556
-
Konferensbidrag (refereegranskat)abstract
- In the method of moments (MoM) for integral equation based numerical electromagnetic field calculation, weakly singular and near-singular surface integrals must be routinely evaluated. Applicable numerical integration schemes are standard Gaussian quadrature or specialized singularity cancellation transformation quadrature. When applying numerical integration, an error is incurred. Qualitative knowledge of the error behaviour and quantitative error estimates are valuable to MoM developers in identifying appropriate quadrature schemes and orders, which lead to increased efficiency and reliability of MoM implementations. An accurate, closed-form error estimate is presented for direct Gaussian product-rule quadrature, as well as for the Radial-Angular-R1-Sqrt transformation scheme.
|
|
| 3. |
- Glazunov, Andres Alayon, 1969, et al.
(författare)
-
Reverberating Dreams - the Story of an OTA Chamber
- 2017
-
Ingår i: 2017 IEEE INTERNATIONAL SYMPOSIUM ON ANTENNAS AND PROPAGATION & USNC/URSI NATIONAL RADIO SCIENCE MEETING. - 1522-3965. - 9781538632840 ; , s. 239-240
-
Konferensbidrag (refereegranskat)abstract
- By the late 90's Prof. Per-Simon Kildal came to the insight that reverberation chambers could be useful tools for characterizing small antennas and wireless devices in multipath channels. This was a revolutionizing idea that was not so well received at first. However, with perseverance, he worked through the challenges to see his dream become a reality. This paper is to recognize Prof. Kildal's contributions carried out at Chalmers, the spin-off company Bluetest, but also the contributions of many other people that have been key to materializing his dream.
|
|
| 4. |
- Hosseinzadegan, Samar, 1987, et al.
(författare)
-
Comparison of Two Forward Models For Electric Field of Microwave Imaging Systems
- 2017
-
Ingår i: 2017 IEEE INTERNATIONAL SYMPOSIUM ON ANTENNAS AND PROPAGATION & USNC/URSI NATIONAL RADIO SCIENCE MEETING. - 1522-3965. - 9781538632840 ; , s. 969-970
-
Konferensbidrag (refereegranskat)abstract
- We propose an alternative numerical method, discrete dipole approximation (DDA), to model the two dimensional electric field of forward solution. Our observations show that discrete dipole approximation can be used as a fast and reliable numerical method on the forward solution of the microwave imaging systems. Two dimensional electric field of the microwave imaging systems has been modelled in finite element method with help of COMSOL Multiphysics as well. The numerical experiments obtained from COMSOL Multiphysics agree well with the discrete dipole approximation approach.
|
|
| 5. |
- Kildal, Per-Simon, 1951, et al.
(författare)
-
OTA Testing of 3G-5G Devices with MIMO: From Anechoic Chambers to Reverberation Chambers and ... Back Again?
- 2017
-
Ingår i: IEEE Antennas and Propagation Society International Symposium. - 1522-3965. - 9781538632840 ; 2017-January, s. 1697-1698
-
Konferensbidrag (refereegranskat)abstract
- The present paper describes the paradigm shift in OTA testing that came with the arrival of the 4G wireless system. The testing was previously mainly done in anechoic Line-Of-Sight (LOS) environments, and now in 4G it is done in reverberation chambers, emulating Rich Isotropic MultiPath (RIMP). Now we are preparing for the 5G wireless system, which is expected to have mm-wave antennas with steerable lobes. This will require OTA testing in anechoic environments again, but with an emphasis on system measurements, i.e. data rate throughput for an arbitrary location and orientation of the user, referred to as Random-LOS.
|
|
| 6. |
- Ludick, D. J., et al.
(författare)
-
Enhancing the Jacobi Method with the CBFM for array antenna analysis
- 2017
-
Ingår i: IEEE Antennas and Propagation Society International Symposium. - 1522-3965. - 9781538632840 ; , s. 727-728
-
Konferensbidrag (refereegranskat)abstract
- The analysis of sparse, disjoint finite antenna array structures is considered in this work. The Method-of-Moments (MoM) based CBFM-enhanced Jacobi technique is presented, and offers an improvement over the standard iterative Jacobi method in terms of convergence and accuracy. By applying the Characteristic Basis Function Method (CBFM) during each iteration the effect of mutual coupling between the array elements can be accounted for more accurately than in the standard Jacobi method. The convergence rate of the method is found to be better than that of the Jacobi technique.
|
|
| 7. |
- Maaskant, Rob, 1978
(författare)
-
Deep Integration: A Paradigm Shift in the Synthesis of Active Antenna Systems
- 2017
-
Ingår i: IEEE Antennas and Propagation Society International Symposium. - 1522-3965. - 9781538632840 ; , s. 1033-1034
-
Konferensbidrag (refereegranskat)abstract
- Deep integration is the visionary future trend of merging conducting, semi-conducting and insulating materials into a single heterogeneous structure that is capable of offering multi-functional RF features. This paper introduces the deep integration concept, describes its potential advantages, lists the key outstanding research challenges, and explains the future perspectives based on historical and current trends in the synthesis of integrated wireless systems for next generation high-frequency applications.
|
|
| 8. |
- Alfonso Alos, Esperanza, 1979, et al.
(författare)
-
Gap waveguide components for millimeter-wave systems. Couplers, filters, antennas, MMIC packaging
- 2012
-
Ingår i: IEEE Antennas and Propagation Society, AP-S International Symposium (Digest). - 1522-3965. - 9784885522703 ; , s. 243-246
-
Konferensbidrag (refereegranskat)abstract
- Design of passive components (couplers, filters and antennas) and MMIC packaging validation intended for RF front ends for microwave links at 38 GHz using gap waveguide technology have been shown. The use of this technology allows all-in-one integration of receiver, transmitter, and diplexer including the antenna into one mechanical unit. These initial designs and studies have been made at the microwave band for validation and measurement purposes, and for comparison with existing technology. They represent the first step towards the application of gap waveguides to millimeter-wave systems, where gap waveguides could have a large potential.
|
|
| 9. |
- Alfonso, E., et al.
(författare)
-
Study of the characteristic impedance of a ridge gap waveguide
- 2009
-
Ingår i: IEEE Antennas and Propagation Society, AP-S International Symposium (Digest). - 1522-3965. - 9781424436477
-
Konferensbidrag (refereegranskat)abstract
- This paper presents a study of the characteristic impedance of a ridge gap waveguide. Ridge gap waveguides belongs to a new metamaterial-based waveguide technology for millimeter and submillimeter waves which emerged recently. A formula for the characteristic impedance of an ideal PEC-over-PMC ridge gap waveguide has been derived. A preliminary numerical study of the characteristic impedance of a real ridge gap waveguide where the PMC is realized by a bed of nails is also presented.
|
|
| 10. |
- Algaba Brazalez, Astrid, 1983, et al.
(författare)
-
Design of a Butler Matrix at 60GHz in Inverted Microstrip Gap Waveguide Technology
- 2015
-
Ingår i: IEEE Antennas and Propagation Society, AP-S International Symposium (Digest). - 1522-3965. ; , s. 2125-2126
-
Konferensbidrag (refereegranskat)abstract
- A four-port Butler matrix is designed at 60GHz in the new gap waveguide technology, inverted microstrip type. The simplicity of doing this circuit in a printed technology and the low loss characteristic makes this design very promising. All the different components of the matrix have been designed and optimized and the complete matrix is currently under optimization.
|
|
| 11. |
- Algaba Brazalez, Astrid, 1983, et al.
(författare)
-
Evaluation of losses of the ridge gap waveguide at 100 GHz
- 2013
-
Ingår i: IEEE Antennas and Propagation Society, AP-S International Symposium (Digest). - 1522-3965. - 9781467353175 ; , s. 1456-1457
-
Konferensbidrag (refereegranskat)abstract
- An evaluation of losses of the Ridge Gap Waveguide (r-GAP) at 100 GHz has been developed in terms of Quality Factor. For this aim, an r-GAP resonator has been designed, simulated and measured. The feeding to the circuit is provided via a transition from Micostrip-to-Ridge Gap Waveguide based in electromagnetic coupling in order to ensure compatibility with the available probe stations.
|
|
| 12. |
- Algaba Brazalez, Astrid, 1983, et al.
(författare)
-
Investigation of a Microstrip-to-Ridge Gap Waveguide transition by electromagnetic coupling
- 2012
-
Ingår i: IEEE Antennas and Propagation Society, AP-S International Symposium (Digest). - 1522-3965. - 9781467304627 ; , s. 1-2
-
Konferensbidrag (refereegranskat)abstract
- A transition from Microstrip to Ridge Gap Waveguide (RGW) has been studied and numerically analyzed in terms of S parameters. The RGW technology shows potential to be used up to THz frequencies. Therefore, good transitions are needed in order to make possible the measurements of RGW components at frequencies above 100 GHz.
|
|
| 13. |
- Aljarosha, Alhassan, 1982, et al.
(författare)
-
Mm-Wave contactless connection for MMIC integration in gap waveguides
- 2016
-
Ingår i: 2016 IEEE Antennas and Propagation Society International Symposium, APSURSI 2016, Fajardo, Puerto Rico, 26 June - 1 July 2016. - 1522-3965. ; , s. 253-254
-
Konferensbidrag (refereegranskat)abstract
- A contactless, broadband and low-loss microstrip-to-groove gap waveguide transition operating at W-band is presented. The principle of operation is based on transforming EM fields from the SIW to the ridge gap waveguide mode via electromagnetic coupling. This is advantageous, since the proposed solution avoids the use of metal contact between the SIW and one of the waveguide parts. Furthermore, metamaterial-based gap waveguide technology provides a resonance-free packaging solution.
|
|
| 14. |
- Bantavis, P. I., et al.
(författare)
-
A Wideband Switched Beam Antenna System for 5G Femtocell Applications
- 2017
-
Ingår i: 2017 IEEE Antennas and Propagation Society International Symposium, Proceedings. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781538632840 ; , s. 929-930
-
Konferensbidrag (refereegranskat)abstract
- This work introduces a wideband switched beam system for femtocell 5G base stations. The system consists of a 4 x 1 Vivaldi linear array and a 4 x 4 Butler matrix able to operate from 1.9-5.1 GHz. A soft surface is introduced along the outer edges of the vivaldi elements of the array for side lobes and back radiation suppression.
|
|
| 15. |
- Beckman, Claes, 1962-, et al.
(författare)
-
On the impact of velocity on the train-to-earth MIMO propagation channel : Statistical observations and qualitative analysis
- 2017
-
Ingår i: 2017 IEEE Antennas and Propagation Society International Symposium, Proceedings. - : IEEE conference proceedings. - 9781538632840 ; , s. 1865-1866
-
Konferensbidrag (refereegranskat)abstract
- We provide measured data collected from 97 trains completing over 7000 journeys in Sweden showing that the throughput over LTE is impacted by train velocity. In order to explain these observations we assume that the underlying causes can be found in the implementation of the MIMO system into LTE Rel. 8 and the diffuse scattering of signals from ground reflections.
|
|
| 16. |
- Björkqvist, Oskar, et al.
(författare)
-
A Novel Efficient Multiple Input Single Output RF Energy Harvesting Rectification Scheme
- 2017
-
Ingår i: 2017 IEEE Antennas and Propagation Society International Symposium, Proceedings. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781538632840 ; , s. 1605-1606
-
Konferensbidrag (refereegranskat)abstract
- In this work an implementation of an ambient radio frequency harvesting system utilizing multiple input single output approach is demonstrated. Measurements of typical ambient radiation have been conducted with respect to power levels and frequency to determine which communication signals are suitable for harvesting. The measurement campaign showed that the WiFi frequency band at 2.45 GHz is a good candidate for indoors applications. A Greinacher voltage doubler is used for the rectification. A multiple input single output - MISO scalable scheme approach is implemented that is able to provide a DC differential output voltage. Simulated and experimental results proved the MISO rectenna to be an efficient scheme for RF harvesting.
|
|
| 17. |
|
|
| 18. |
- Capek, Miloslav, et al.
(författare)
-
Numerical Benchmark based on characteristic modes of a spherical shell
- 2017
-
Ingår i: 2017 IEEE Antennas and Propagation Society International Symposium, Proceedings. - 9781538632840 ; 2017-January, s. 965-966
-
Konferensbidrag (refereegranskat)abstract
- Characteristic modes of a spherical shell are found analytically and compared with numerical solutions acquired from both in-house and commercial packages. These studies led to a proposal of several independent benchmarks, all with analytically known results. Dependence on mesh size, electrical size and other parameters can easily be incorporated. It is observed that all contemporary implementations have limitations.
|
|
| 19. |
|
|
| 20. |
- Carlsson, Jan, 1962, et al.
(författare)
-
Antenna Research at CHASE – Chalmers Antenna Systems Excellence Centre
- 2012
-
Ingår i: IEEE Antennas and Propagation Society, AP-S International Symposium (Digest). - 1522-3965. - 9784885522703 ; , s. 215-218
-
Konferensbidrag (refereegranskat)abstract
- Chase is one of a total of eighteen 'VTNN Excellence Centres' that are funded by VINNOVA, the Swedish Governmental Agency for Innovation Systems. The aim of these centres is to provide a forum for collaboration between the private and public sectors, universities and colleges, research institutes and other organisations that conduct research. The Chase centre was started in 2007 and has a budget of at least 23 million Euro over ten years with cash and in kind contributions. The research activities in Chase cover antennas and antenna system aspects, and the industrial interests are mainly in Wireless Communications, Remote Sensing and Medical Applications of Microwaves. The projects are chosen based on industrial needs, usefulness for society and global sustainability.
|
|
| 21. |
- Chernikov, Viktor, 1998, et al.
(författare)
-
Design Considerations for Focal-Plane Array Antennas for 6G Millimeter-Wave Backhaul Links
- 2023
-
Ingår i: IEEE Antennas and Propagation Society, AP-S International Symposium (Digest). - 1522-3965. ; 2023-July, s. 765-766
-
Konferensbidrag (refereegranskat)abstract
- We present three designs of W-band Focal-Plane Array (FPA) antennas as possible candidates for the next-generation millimeter-wave (mmWave) backhaul links. The considered FPAs comprise different types of waveguide antenna elements and are optimized to feed a prime-focus reflector with 400 mm aperture diameter. The main design goal is to realize a high directivity (50 dBi) with minimum beam scan loss, while complying with the strick side-lobe level requirements (ETSI class 3).
|
|
| 22. |
- Cismasu, Marius, et al.
(författare)
-
Optimal Charges and Currents on Small Wire Antennas
- 2012
-
Ingår i: IEEE Antennas and Propagation Society International Symposium (APSURSI), 2012. - 1522-3965 .- 1947-1491. - 9781467304610 ; , s. 1-2
-
Konferensbidrag (refereegranskat)abstract
- The optimum surface charge on a thin wire antenna is computed using a variational formulation in the low-frequency limit. This charge and its corresponding current are compared with simulation results for self resonant structures. The comparison shows that the currents and charges on self resonant structures resemble those in the static limit to a great extent.
|
|
| 23. |
- Dahlberg, Oskar, et al.
(författare)
-
A Novel 32 Port Cube MIMO Combining Broadside and Endfire Radiation Patterns for Full Azimuthal Coverage - A Modular Unit Approach for a Massive MIMO System
- 2017
-
Ingår i: 2017 IEEE Antennas and Propagation Society International Symposium, Proceedings. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781538632840 ; , s. 1641-1642
-
Konferensbidrag (refereegranskat)abstract
- In this paper we propose a novel 32 antenna port multiple-input-multiple-output (MIMO)-cube. The total volume of the cube is 320 x 320 x 120 mm(3) . On two faces, endfire radiating linear tapered slot antennas (LTSAs) are placed and on the remaining sides, a mix of both LTSAs and broadside patch antennas are placed. In total 16 LTSAs and 8 dual polarized patches are used. The LTSA is designed to operate at the GSM and 3G bands, from 1.7 to 2.3 GHz. A corrugation pattern is introduced along the edges of the LTSAs covering one face to increase directivity and decrease sidelobes. The LTSAs are placed in two different orientations in order to receive two polarisations. The patch antenna is dual band and dual polarized. It operates in the frequency bands 2.4-2.5 and 5.45-5.6 GHz where Wi-Fi communication is made. The spatial placement, with antennas on all sides of the cuboid, ensures full azimuthal coverage despite the high directivity of the antennas. Using different antennas on different faces of the cube further optimizes the volume efficiency of the cube for azimuthal coverage.
|
|
| 24. |
- 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.
|
|
| 25. |
- Engvall, Erik K, 1984, et al.
(författare)
-
A study of uncertainty models in a reverberation chamber at NIST
- 2012
-
Ingår i: IEEE Antennas and Propagation Society, AP-S International Symposium (Digest). - 1522-3965. - 9781467304627
-
Konferensbidrag (refereegranskat)abstract
- The reverberation chamber has become a good alternative for over-the-air (OTA) testing of small antennas. Here the uncertainty of total radiated power measurements is evaluated for a reverberation chamber at National Institute of Standards and Technology (NIST), Boulder, Colorado. A procedure for measuring the uncertainty based on the standard deviation of nine different antenna orientations in the RC has been used.
|
|
| 26. |
- Fayazi, Seyedeh Shaghayegh, et al.
(författare)
-
Microwave imaging of near-field object using ultra-wideband synthetic aperture radar algorithm
- 2012
-
Ingår i: 2012 IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM (APSURSI). - 1522-3965. - 9781467304627
-
Konferensbidrag (refereegranskat)abstract
- A simple procedure that suppresses artefact from ultra-wideband (UWB) synthetic aperture radar (SAR) images is proposed and verified using experimental data. The proposed imaging solution is useful for imaging small objects located in the near-field region with less ambiguity.
|
|
| 27. |
|
|
| 28. |
- Glazunov, Andres Alayon, 1969, et al.
(författare)
-
Zero-forcing MIMO efficiency in random line-of-sight
- 2016
-
Ingår i: 2016 IEEE Antennas and Propagation Society International Symposium, APSURSI 2016, Fajardo, Puerto Rico, 26 June - 1 July 2016. - 1522-3965. - 9781509028863 ; , s. 331-332
-
Konferensbidrag (refereegranskat)abstract
- We derive the Multiple-Input Multiple-Output (MIMO) efficiency of the Zero-Forcing (ZF) receiver algorithm in Random Line-Of-Sight (Random-LOS). We make use of the Probability-of-Detection (PoD) curves based on the ideal digital threshold receiver model in the derivations. We show that the MIMO efficiency in this case, is mainly determined by two factors: the smallest channel gain of the two available bit streams and the non-orthogonality coefficient. This must be considered when designing antenna systems for efficient communication at higher frequencies since Random-LOS propagation will be dominating.
|
|
| 29. |
|
|
| 30. |
- Hammar, Arvid, 1986, et al.
(författare)
-
A 340 GHz High Gaussicity Smooth Spline Horn Antenna for the STEAMR Instrument
- 2014
-
Ingår i: IEEE Antennas and Propagation Society, AP-S International Symposium (Digest). - 1522-3965. - 9781479935383 ; , s. 649-650
-
Konferensbidrag (refereegranskat)abstract
- We present the design, fabrication and measure-ments of a smooth walled spline feed horn antenna for the satellite borne climate research instrument STEAMR operating at 340GHz. A method has been developed which, for a certain desired beam waist, can be used to optimize the horn profile for high Gaussicity and ultra-low sidelobes. The simulated performance of the horn achieves a beam waist of 1.9 mm over the band 323-357 GHz with Gaussian coupling efficiency exceeding 98%. The peak cross-polar sidelobes are below -28 dB over the required frequency band. For cost effective manufacturing with high repeatability, the smooth wall spline profile is drilled in out from a metal block using a custom made broach. To validate the design and fabrication, planar measurements of the phase and amplitude have been performed and from measured E-field vital horn parameters have been extracted.
|
|
| 31. |
- Harrysson, Fredrik, et al.
(författare)
-
Evaluation of user hand and body impact on multiple antenna handset
- 2010
-
Ingår i: [Host publication title missing]. - 1522-3965 .- 1947-1491. - 9781424449675
-
Konferensbidrag (refereegranskat)abstract
- From our experimental investigation of multiple-antenna performance and user impact of a realistic mobile terminal setup, we find that apart from the important loss of efficiency due to the user hand, the impact on the individual antennna elements and the directional impact of the user body shadowing have quite small influence on the diversity and capacity performance. It is found that the top and bottom placement of antennas within the handset case are the most efficient to be used with up to two antenna elements. There are, however, significant diversity and capacity gain that can be explored by using four distributed antennas even if only two radio chains are available through hybrid selection and combining schemes. It was also found that the practical method of choosing antennas based on signal power for 2 branch MIMO with 4 available handset antennas, performs well compared to the optimal solution.
|
|
| 32. |
- Hosseinzadegan, Samar, 1987, et al.
(författare)
-
Integrating the discrete dipole approximation forward solver with a microwave tomography algorithm
- 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. 2295-2296
-
Konferensbidrag (refereegranskat)abstract
- The discrete dipole approximation (DDA) has been suggested as a viable alternative method for computing the forward solutions during the iterative reconstruction process used in microwave tomography. While efficient algorithms such as finite difference time domain and finite elements have been successfully used by multiple groups, the forward solution time remains the time-limiting step. The DDA has been shown to be accurate and efficient as a forward solver. However, the configuration of the imaging scenario can have a significant impact on its efficiency. We examine two possible forward solution set-ups and describe the benefits with respect to implementing the DDA.
|
|
| 33. |
- Hussain, Ahmed, 1985, et al.
(författare)
-
Modeling system throughput of single and multi-port wireless LTE devices
- 2012
-
Ingår i: IEEE Antennas and Propagation Society, AP-S International Symposium (Digest). - 1522-3965. - 9781467304627
-
Konferensbidrag (refereegranskat)abstract
- We have recently introduced a simple theoretical model for estimating the relative throughput of LTE devices. We validated the model through measurements performed in reverberation chamber for 1×2 SIMO with 90ns channel delay spread. In the present paper, we extend our previous study to compare the frequency diversity offered by different channel delay spreads emulated in reverberation chamber for SISO and 1×2 SIMO configurations
|
|
| 34. |
|
|
| 35. |
- Kildal, Per-Simon, 1951, et al.
(författare)
-
Direct Coupling as a Residual Error Contribution During OTA Measurements of Wireless Devices in Reverberation Chamber
- 2009
-
Ingår i: 2009 IEEE International Symposium on Antennas and Propagation and USNC/URSI National Radio Science Meeting, APSURSI 2009; North Charleston, SC; United States; 1 June 2009 through 5 June 2009. - 1522-3965. - 9781424436477 ; , s. Art. no. 5171903-
-
Konferensbidrag (refereegranskat)abstract
- We have presented an improved theory for the uncertainty of measurements in reverberation chamber. The theory is obtained by including the error due to the direct coupling between the antenna under test and the wall-mounted antennas. The theory includes the Rician K-factor that can be estimated from simple formulas, and an empirical mechanical stirring bandwidth Bmech that is adjusted to get good agreement with the measured STDs. However, Bmech is fixed for a given chamber and stirrer configuration. The new theory is able to describe variations of uncertainty with frequency and loading, and it can very well predict the degradation when platform and polarization stirring is not used. The validation of the theory is representative for efficiency measurements, but it will be equivalent for measuring total radiated power and receiver sensitivity.
|
|
| 36. |
- Kildal, Per-Simon, 1951
(författare)
-
Metasurfing since 1987 - A personal story involving soft and hard surfaces, EBG surfaces, cloaking, gap waveguides and mass production
- 2014
-
Ingår i: IEEE Antennas and Propagation Society, AP-S International Symposium (Digest). - 1522-3965. ; , s. 529-530
-
Konferensbidrag (refereegranskat)abstract
- This paper will describe my personal experiences with what today is referred to as metamaterials, and in particular in my case metasurfaces. My journey starts with the introduction of a concept of soft and hard surfaces in 1988, being a generalization of the corrugated surface, and today most conveniently represented by canonical PEC/PMC strip grids. The first industrial application of the soft surface was the patent-protected hat feed in 1987. This has until now been manufactured in more than 940 000 copies mainly for Ericsson's successful MINILINK product. The anisotropic soft surface is a forerunner of the isotropic EBG surface appearing around year 2000, and the hard surface was used for cloaking 10 years before cloaking became a popular research topic in 2007. The concept of soft and hard surfaces has since 2009 developed into a novel gap waveguide technology. The gap waveguide technology is used to package microstrip and CPW circuits, but also to replace them. The gap waveguides can have similar low-loss performance as solid rectangular waveguides, but they can be realized in a much simpler way in particular at millimeter- and submillimeterwave frequencies. Good performance has been demonstrated for filters, transitions, MMIC packaging, corporate distribution networks, and slot and horn array antennas. The first commercial applications can come soon, probably at 60 GHz.
|
|
| 37. |
- Kildal, Per-Simon, 1951, et al.
(författare)
-
Performance of different theoretical small antennas in isotropic 3-D and horizontal 2-D multipath environments with application to OTA testing
- 2010
-
Ingår i: 2010 IEEE International Symposium on Antennas and Propagation, Toronto, July 11-17, 2010. - 1522-3965. - 9781424449682
-
Konferensbidrag (refereegranskat)abstract
- We have studied the performance of antennas in inherently polarization-balanced horizontal 2-D multipath environments with angles of arrival in the horizontal plane only. The average received power may vary up to 3 dB depending on type of small antenna and its orientation, and, the observed polarization balanced may be anything between +3 and 3 dB, depending on the antenna by which it is measured.
|
|
| 38. |
- kishk, M. A., et al.
(författare)
-
Electromagnetic scattering from circular cylinders with PEC/PMC boundaries
- 2010
-
Ingår i: 2010 IEEE International Symposium on Antennas and Propagation, Toronto, July 11-17, 2010. - 1522-3965. - 9781424449675
-
Konferensbidrag (refereegranskat)abstract
- The electromagnetic scattering from a circular cylinder with helical PEC/PMC boundary due to oblique plane wave incidence was analyzed using the series solution. The solution was verified using the method of moments.
|
|
| 39. |
- Klein, Benjamin, 1981, et al.
(författare)
-
System noise calculations over the decade bandwidth of the Eleven feed for radio telescope applications
- 2010
-
Ingår i: 2010 IEEE International Symposium on Antennas and Propagation, Toronto, July 11-17, 2010. - 1522-3965. - 9781424449682
-
Konferensbidrag (refereegranskat)abstract
- The ability to cool the entire system improves system performance by a factor of two to four times; for the cooled case. This requires ambient systems to increase reflector diameters in proportion to achieve similar sensitivity. Additionally, the requirements on matching are relaxed in cooled systems, as the not-included variation of the LNA due to the noise mismatch is much smaller in a cooled system than in a non-cooled system. The calculations presented provide a meaningful reference to quickly compare systems, for both engineers and scientists. However, further work is ongoing into more accurate noise models and computer simulations. There is also ongoing work to verify results experimentally.
|
|
| 40. |
- Li, Hui, et al.
(författare)
-
Generating multiple characteristic modes below 1 GHz in small terminals for MIMO antenna design
- 2013
-
Ingår i: IEEE International Symposium on Antennas and Propagation, 2013. - 1947-1491 .- 1522-3965. - 9781467353175 ; , s. 180-181
-
Konferensbidrag (refereegranskat)abstract
- Designing multiple antennas in small terminals at frequency bands below 1 GHz is challenging due to severe mutual coupling among antenna elements. The severe coupling is often the result of simultaneous excitation of the fundamental characteristic mode of the terminal chassis by more than one antenna element. In this work, we propose to solve the coupling problem by manipulating the chassis structure to allow more than one characteristic mode to resonate at frequencies below 1 GHz. To demonstrate our design concept and its practicality, we show the opportunistic use of the metallic bezel popular in smartphone design for obtaining two characteristic modes that can be efficiently excited by antenna elements at 0.81 GHz. Due to the inherent orthogonality of the modes, proper excitation of these modes by two antenna elements will result in orthogonal radiation patterns and high isolation between the antenna ports. Therefore, the proposed approach enables the effective use of the chassis to achieve MIMO antennas with good performance.
|
|
| 41. |
- Liao, Qingbi, et al.
(författare)
-
Channel Capacity Analysis of Different Mobile Antenna Array Topologies in the Outdoor Urban Environment for 5G mm Wave System
- 2017
-
Ingår i: 2017 IEEE Antennas and Propagation Society International Symposium, Proceedings. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781538632840 ; , s. 1473-1474
-
Konferensbidrag (refereegranskat)abstract
- The 15 and 28 GHz frequency bands have been identified as interesting candidates for future 5G cellular communication systems. In this paper, based on ray-tracing simulations, we investigate the channel capacities at 15 and 28 GHz for a number of different array processing techniques, including beamforming, spatial multiplexing, and two types of hybrid beamforming. This is done for an 8 x 32 multiple input multiple output system, for the single user case. The hybrid beamforming techniques combines the beamforming and spatial multiplexing techniques, in order to reduce the number of analog-to-digital converters and thereby reducing the system complexity, while still maintaining multiplexing capabilities for improved system capacities. The achieved channel capacities the hybrid beamforming techniques with up to four parallel streams outperforms pure beamforming, but does not reach capacities close to that of full spatial multiplexing. This indicates that the outdoor channel can support multiplexing of more than four parallel data streams to a single user.
|
|
| 42. |
- Lötbäck Patané, Christian, 1985, et al.
(författare)
-
LTE MIMO throughput measurement method for characterization of multi-antenna terminal performance
- 2011
-
Ingår i: 2011 IEEE International Symposium on Antennas and Propagation, Spokane, USA, 3-8 July, 2011. - 1522-3965. - 9781424495627 ; , s. 43-46
-
Konferensbidrag (refereegranskat)abstract
- This paper presents experiences and results from LTE MIMO throughput measurements of a USB dongle in a reverberation test system. The measurements are performed with the dongle itself and also when it is connected to external diversity antennas with high and low correlation. Three different maximum bit rates are used, 59, 70 and 81 Mbps. The results illustrate that it is possible to separate a good antenna design from a bad from reverberation chamber measurements. Also, the effect of using a laptop test fixture, or a laptop dummy, instead of having the host computer present in the chamber, is demonstrated. It is shown that the noise induced by the host computer degrades the performance of the dongle.
|
|
| 43. |
- Mattsson, Martin, et al.
(författare)
-
A high gain Dual-Polarised Differential Rectenna for RF Energy Harvesting
- 2017
-
Ingår i: 2017 IEEE Antennas and Propagation Society International Symposium, Proceedings. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781538632840 ; , s. 1609-1610
-
Konferensbidrag (refereegranskat)abstract
- A rectenna for radio frequency (RF) energy harvesting is presented in this paper. We introduce a novel technique for RF rectification that is based on differential field sampling and a Greinacher voltage doubler rectifier. The proposed rectification antenna is a dual polarized patch with 4 ports that operates for the WiFi frequency band of 2.4-2.5 GHz and has a gain of 6.75 dB at each port. The proposed novel topology doubles the amount of input power accepted for each polarization and then quadruples the overall output power. In addition we have a differential output voltage source that is typically required for the electronics connected to the harvesting system.
|
|
| 44. |
- McPhedran, Ross, et al.
(författare)
-
Resonances and Fields near Metamaterial Inclusions
- 2012
-
Ingår i: Antennas and Propagation Society International Symposium (APSURSI), 2012 IEEE. - 1522-3965 .- 1947-1491. - 9781467304627
-
Konferensbidrag (refereegranskat)abstract
- We consider systems of particles in two dimensions with negative dielectric permittivity and sharp corners. The field divergences near the corners of the inclusions are non-square-integrable for negative permittivities in a range depending on the corner angle, and the leading term for small distances is provided by the static term. We have developed a highly accurate numerical method which uses adaptive techniques to resolve field behaviour near the corners. We use this to elucidate the resonant spectrum associated with the effective permittivity of arrays of such particles, and in particular its behaviour as the particles approach touching.
|
|
| 45. |
- Miers, Zachary, et al.
(författare)
-
Design of multi-antenna feeding for MIMO terminals based on characteristic modes
- 2013
-
Ingår i: IEEE International Symposium on Antennas and Propagation, 2013. - 1522-3965 .- 1947-1491. - 9781467353175 ; , s. 182-183
-
Konferensbidrag (refereegranskat)abstract
- Conventional antennas in single-antenna terminals that resonate at frequencies lower than 1 GHz usually rely on the chassis as the main radiator. To effectively exploit chassis excitation for MIMO terminals, each of the multiple antennas is required to excite one distinct chassis mode. However, in today's terminals, there is typically only one chassis mode that can radiate efficiently at frequencies below 1 GHz. Fortunately, it has been shown that minor modifications in the chassis structure can cause more than one mode to resonate at these frequencies. Nevertheless, proper antenna feeding methods are needed to practically tap into these modes. In this paper, we propose a general technique to feed orthogonal chassis modes of a given conducting structure using the theory of characteristic modes. By separating a radiating structure into individual modal currents, the near field radiating properties are exploited for capacitive or inductive feeding without significant coupling to other orthogonal modes of radiation. As a proof of concept, we apply the technique to feed a modified terminal chassis that has two significant characteristic modes at 0.89 GHz.
|
|
| 46. |
- Miers, Zachary, et al.
(författare)
-
Design of multimode multiband antennas for MIMO terminals using characteristic mode analysis
- 2014
-
Ingår i: IEEE International Symposium on Antennas and Propagation, 2014. - 1947-1491 .- 1522-3965. - 9781479935383 ; , s. 1429-1430
-
Konferensbidrag (refereegranskat)abstract
- Characteristic mode analysis provides unparalleled insights into designing high performance multiple-input multiple-output (MIMO) terminal antennas at frequencies where the antenna elements are constrained to be electrically small. Conventionally, an electrically small single-antenna utilizes the fundamental characteristic mode of the terminal chassis to obtain sufficient bandwidth while maintaining high radiation efficiency. However, modern MIMO terminals require two or more antennas per frequency band, and they tend to excite the same fundamental chassis mode, resulting in severe coupling and correlation, and poor overall system performance. Recently, characteristic mode analysis of the chassis is proposed to design highly efficient multimode multiband MIMO antennas with significant bandwidth using electrically small feed elements. Two distinct and excitable characteristic modes were created at frequencies above and below 1 GHz, for a typical smartphone’s form factor. This paper provides an overview of the method and highlights its versatility for practical implementation in standard plastic cased smartphones as well as in the popular metal-bezeled smartphones, with only minor modifications to the chassis.
|
|
| 47. |
- Miers, Zachary Thomas, et al.
(författare)
-
Restoring characteristic eigenvalues as reactive powers for simple and complex media in surface integral formulations
- 2017
-
Ingår i: 2017 IEEE Antennas and Propagation Society International Symposium, Proceedings. - 9781538632840 ; 2017-January, s. 43-44
-
Konferensbidrag (refereegranskat)abstract
- The Theory of Characteristic Modes (TCM) has recently been shown to be beneficial in solving a wide variety of complex electromagnetic problems. However, there are still open issues in using TCM to analyze objects which consist of simple or complex media. Either a volume integral equation (VIE) or a surface integral equation (SIE) is required to solve for the characteristic modes of these objects. Herein, we overview the important issue that the characteristic eigenvalues obtained from SIE formulations are not related to the modal reactive power, unlike the classical TCM definition. A recently proposed solution that restores the modal reactive power interpretation of characteristic eigenvalues is described. A numerical example is provided to demonstrate the differences between the SIE eigenvalues and the restored eigenvalues.
|
|
| 48. |
- Orlenius, Charlie, 1976
(författare)
-
Antenna performance characterization of multi-antenna terminals used in Multiple-Input-Multiple-Output communication systems
- 2010
-
Ingår i: 2010 IEEE International Symposium on Antennas and Propagation, Toronto, July 11-17, 2010. - 1522-3965. - 9781424449675
-
Konferensbidrag (refereegranskat)abstract
- With new third and fourth generation mobile communication systems emerging, there has been an increased focus on the antenna performance of mobile terminals. Common for most new communication systems currently deployed and under development is the demand for multi-antenna technology, such as multiple-input-multiple-output (MIMO). In order to reach increased data rates it is essential to be able to make use of the potential spatial multiplexing gain of a multipath propagation environment. For design optimization of these multi-element antennas, a reliable and relevant measurement method for characterizing the antenna performance is important. In this paper, a method using the reverberation chamber is presented together with a discussion on how to analyze the results in order to distinguish good and bad antenna designs from each other.
|
|
| 49. |
- Orlenius, Charlie, 1976, et al.
(författare)
-
Evaluation of multi element antennas in reverberation chamber
- 2012
-
Ingår i: IEEE Antennas and Propagation Society, AP-S International Symposium (Digest). - 1522-3965. - 9781467304627
-
Konferensbidrag (refereegranskat)abstract
- This paper focuses on the latest advances in the use of reverberation chambers for active device testing. Contained are description and comparison of different figure-of-merits that are applicable to multi element antennas, with a specific focus on LTE devices with MIMO capability. There are two new parameter concepts introduced: Modified Total Isotropic Sensitivity measurements to include MIMO signaling, and a Throughput Threshold Level for simplified quantification of data bit throughput measurement results.
|
|
| 50. |
|
|
