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Träfflista för sökning "L773:1522 3965 OR L773:9781424495627 srt2:(2015-2019)"

Sökning: L773:1522 3965 OR L773:9781424495627 > (2015-2019)

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1.
  • 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.
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2.
  • 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.
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3.
  • 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.
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4.
  • 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.
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5.
  • 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.
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6.
  • 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.
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7.
  • 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.
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8.
  • 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.
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9.
  • 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.
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10.
  • 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.
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11.
  • 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.
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12.
  • 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.
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13.
  • Prinsloo, D.S, et al. (författare)
  • Quad-Mode Antenna for Wide-Scan Sparse Arrays
  • 2015
  • Ingår i: IEEE Antennas and Propagation Society, AP-S International Symposium (Digest). - 1522-3965. - 9781479978151 ; 2015-October, s. 1516-1517
  • Konferensbidrag (refereegranskat)abstract
    • A conical quad-mode antenna excited through four orthogonal transverse electromagnetic modes is presented. The radiation characteristics of each mode are validated through measurements, illustrating the complimentary nature of the four far-field radiation patterns through which near-hemispherical field-of-view coverage can be achieved.
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14.
  • Shah, Waqar Ali, 1987, et al. (författare)
  • W-band spatial power combiner and splitter in gap waveguide technology
  • 2016
  • Ingår i: 2016 IEEE Antennas and Propagation Society International Symposium, APSURSI 2016, Fajardo, Puerto Rico, 26 June - 1 July 2016. - 1522-3965. ; , s. 255-256
  • Konferensbidrag (refereegranskat)abstract
    • A passive power splitter and combiner has been designed in-between two metallic ground plates using gap waveguide technology. The measured insertion loss is smaller than 2.3 dB and the return loss is larger than 10 dB over the entire W-band (75-110 GHz). The design procedure has been detailed and the simulated and measured results for the proposed structure are shown. The designed structure can be used as a passive power splitter or combiner, as a grid amplifier in a back-to-back RF chain, or as a quasi-optical beamforming component in beam steering antenna arrays.
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15.
  • Uz Zaman, Ashraf, 1975, et al. (författare)
  • Millimeter wave Microstrip Fed Slot Array Antenna with PMC Packaging for Future 5G Systems
  • 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. 1513-1514
  • Konferensbidrag (refereegranskat)abstract
    • This paper deals with slot array antenna fed by PMC packaged microstrip lines at 30GHz frequency range. The slots are etched in the ground plane of the microstrip substrate. The microstrip feeding line is placed on the other side of the substrate. Also, a PMC layer is placed on top of the feeding microstrip line to stop surface waves or any unwanted field leakage or radiation from the feeding line. In this work, the PMC surface is realized by periodic metal pin structure. The antenna works at 30GHz band with reasonable S-11 and radiation performance.
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16.
  • Villiers, Dirk I. L. de, et al. (författare)
  • Diffraction and Pattern Perturbation Effects in Offset Gregorian Reflector Antennas with Wideband Feeds
  • 2015
  • Ingår i: IEEE Antennas and Propagation Society, AP-S International Symposium (Digest). - 1522-3965. - 9781479978151 ; 2015-October, s. 1520-1521
  • Konferensbidrag (refereegranskat)abstract
    • The offset Gregorian reflector system of the SquareKilometer Array radio telescope is required to operate with wideband feed (WBF) antennas down to very low frequencies, where reflectors become (electrically) relatively small. The considered WBF technologies are the log-periodic (Eleven) antenna and the quadruple-ridged flared horn. This paper investigates some of the performance degradation effects that are specific for the low frequencies and typical for these WBFs, including the feed pattern perturbations and diffraction. Several performance metrics, such as the antenna receiving sensitivity and side lobe levels are considered.
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17.
  • Vosoogh, Abbas, 1984, et al. (författare)
  • Simple and Broadband Transition Between Rectangular Waveguide and Groove Gap Waveguide for mm-Wave Applications
  • 2018
  • Ingår i: IEEE Antennas and Propagation Society International Symposium. - 1522-3965. - 9781538671023 ; , s. 1101-1102
  • Konferensbidrag (refereegranskat)abstract
    • A vertical wideband transition between a standard WR-15 rectangular waveguide (RW) and groove gap waveguide (GGW) in the V-band is presented. A simple step is applied to achieve a good impedance matching in transition between the RW and the GGW. A back-to-back transition is designed and fabricated to verify the simulation results. The measured results of the fabricated prototype show the insertion loss of less than 0.2 dB and the input reflection coefficient better than -16 dB over almost the whole V-band (50-75 GHz).
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18.
  • Wu, Runqi, 1995, et al. (författare)
  • A Broadband Dual-polarized Capped Bow-tie 2x2 Antenna Array for 28 GHz Band in 5G Systems
  • 2018
  • Ingår i: 2018 IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM ON ANTENNAS AND PROPAGATION & USNC/URSI NATIONAL RADIO SCIENCE MEETING. - 1522-3965. - 9781538671023 ; , s. 825-826
  • Konferensbidrag (refereegranskat)abstract
    • With the development of the fifth generation (5G) communications, dual-polarization base station antennas have increasingly attracted a lot of attention. In this paper, a broadband high-efficiency dual-polarized capped bow-tie antenna array is presented. Simulation results show that the bandwidth of the proposed antenna is 24-36.8 GHz, with its return loss better than 10 dB and the stable coverage. The directivities vary from 8 to 12dBi and the relative cross-polar level is below -10dB over the most of band. It has a simple and compact structure, and is ready to be extended for large array antennas with massive MIMO performance used in 5G communications.
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19.
  • Yang, Jian, 1960, et al. (författare)
  • PCB Based UWB mm-Wave Smart Capped Bowtie Array for 5G Communication Systems
  • 2018
  • Ingår i: IEEE Antennas and Propagation Society International Symposium. - 1522-3965. - 9781538671023 ; , s. 631-632
  • Konferensbidrag (refereegranskat)abstract
    • This paper gives an overview of the preliminary development of a new antenna technology – the UWB capped Bowtie array antenna aiming to the applications in 5G wireless communication systems. The capped Bowtie antenna has not only the ultra-wideband active reflection coefficient performance but also a UWB stable radiation functions of the array element. A novel solution to the aggregation for tightly coupled capped Bowtie array is also presented briefly in the paper.
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20.
  • Young, A., et al. (författare)
  • Efficient Wideband Gain Modeling for Interferometric Imaging Arrays in Radio Astronomy
  • 2015
  • Ingår i: IEEE Antennas and Propagation Society, AP-S International Symposium (Digest). - 1522-3965. - 9781479978151 ; 2015-October, s. 1374-1375
  • Konferensbidrag (refereegranskat)abstract
    • Current and future interferometric imaging arraysin radio astronomy may be limited by the accuracy with which various direction-dependent effects, such as the antenna gain patterns, can be corrected. Doing this in an efficient manner during the calibration and imaging process is especially difficult due to these effects often being also baseline-dependent. A newly proposed method, called A-stacking, offers a solution through the use of a parametrized model in which basis functions account for the direction-dependence and the expansion coefficients account for the baseline-dependence. This approach provides a simple trade-off between computational complexity and calculation accuracy. Herein the use of the A-stacking method to model direction-dependent effects over a very wide frequency band is investigated.
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