| 1. |
- Glazunov, Andres Alayon, 1969, et al.
(författare)
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Semi-Analytical Model of the Rician K-Factor
- 2020
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Ingår i: Radio Science. - 0048-6604 .- 1944-799X. ; 55:11
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Tidskriftsartikel (refereegranskat)abstract
- The analysis of the performance of 5G wireless communication systems employing Massive MIMO at millimeter-wave frequencies is of great practical relevance. Of special relevance are the signal fluctuations. In the present paper, we introduce a semi-analytical model for a generic scattering environment by using randomly distributed resonant scatterers to investigate the impact of the size of the scattering environment, the scatterer density, and the number of scatterers on the signal variability in terms of the Rician K-factor as a function of frequency. We further present an investigation of the impact of scattering on the frequency dependence of the signal fading statistics in the 500 MHz–100 GHz band. The simplified model is also verified against full-wave simulation using the Method of Moments (MoM).
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| 2. |
- Glazunov, Andres Alayon, 1969, et al.
(författare)
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Simulating the MIMO Efficiency of Antennas
- 2017
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Ingår i: 2017 INTERNATIONAL SYMPOSIUM ON ANTENNAS AND PROPAGATION (ISAP 2017). - 9781538604656
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Konferensbidrag (refereegranskat)abstract
- Presented is a mathematical model to compute the multiple-input multiple-output efficiency of a multiport antenna in the single-user case. The evaluation comprises the performance of a zero-forcing receiver in two limiting propagation scenarios, i.e., the random line-of-sight and the rich isotropic multipath channels.
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| 3. |
- Mansouri Moghaddam, Sadegh, 1987, et al.
(författare)
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A planar dual-polarized ultra-wideband millimeter-wave array antenna
- 2018
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Ingår i: IET Conference Publications. - : Institution of Engineering and Technology.
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Konferensbidrag (refereegranskat)abstract
- We present a dual-polarized ultra-wideband element in an infinite large array condition for planar phased array antennas in mm-wave applications. The array antenna consists of tightly-coupled bowties in a dual-offset configuration. In order to simplify the manufacturing process and eliminate the scalability limitation, a new feeding network is employed. The feeding is inspired by magneto-electric dipoles (MEDs) and planar ultra-wideband array antennas (PUMAs). Hence, the feeding is integrated with the horizontally oriented radiating bowties and removes the need for the external baluns. The simulated antenna shows relative bandwidths of 2.3 : 1 and 3 : 1 at VSWR<3, for maximum scanning angles of 60° and 45°, respectively, at both E- and H-planes.
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| 4. |
- Mansouri Moghaddam, Sadegh, 1987, et al.
(författare)
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A Planar Single-Polarized Ultra-Wideband Antenna Element for Millimeter-Wave Phased Array
- 2018
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Ingår i: 2018 INTERNATIONAL SYMPOSIUM ON ANTENNAS AND PROPAGATION (ISAP). - 9788957083048
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Konferensbidrag (refereegranskat)abstract
- We propose a single-polarized ultra-wideband element for mm-wave phased arrays. The element is comprised of tightly-coupled bowties fed by a specific configuration of plated via holes. The corresponding feeding network is implemented in such a way to eliminate the use of an external balun. In addition, it provides the possibility to be manufactured by PCB technology. The simulated element has a relative bandwidth of 2.56:1 at a reflection coefficient better than 8 dB while scanning up to 45 degrees. The reflection coefficient remains below 6 dB for a maximum scanning angle of 60 degrees.
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| 5. |
- Mansouri Moghaddam, Sadegh, 1987, et al.
(författare)
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A self-grounded dual-polarized wideband bowtie with improved MIMO performance in Random-LOS
- 2016
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Ingår i: 2016 IEEE Antennas and Propagation Society International Symposium, APSURSI 2016 - Proceedings. - 9781509028863 ; , s. 531-532
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Konferensbidrag (refereegranskat)abstract
- We present a new improved design of the self-grounded dual-polarized wideband bowtie antenna for MIMO application. The antenna is evaluated for the case when the original four ports are combined to two orthogonally polarized ports. The new antenna covers the previous bandwidth but has lower gain and wider beamwidth over the frequency band of interest. The 2×2 MIMO performance of the antenna in Random-Line of Sight (Random-LOS) is evaluated for two bitstreams using the threshold receiver model and Zero-Forcing receiver. The simulated results show an improvement in terms of MIMO multiplexing coverage over a hemisphere for two bitstreams, compared to the previous solution.
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| 6. |
- Mansouri Moghaddam, Sadegh, 1987, et al.
(författare)
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Comparison of 2-bitstream polarization-MIMO performance of 2 and 4-port bowtie antennas for LTE in random-LOS
- 2016
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Ingår i: 2015 International Symposium on Antennas and Propagation, ISAP 2015.
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Konferensbidrag (refereegranskat)abstract
- We evaluate the performance of a dual-polarized wideband antenna in terms of polarization-MIMO in Random-LOS for two different modes of operation: 2 and 4-port excited mode. The 2-port mode was obtained by differential excitation of two opposite ports of the 4-port design by using two baluns. The Zero-Forcing receiver throughput is evaluated based on the Probability of Detection of two bitstreams when orthogonal polarizations provide the MIMO subchannels. Assuming a uniform distribution for the Angle of Arrivals and orthogonally polarized waves incident on the antennas, the overall PoD over coverage cones of 30°, 60° and 90° are presented. The 2-bitstream multiplexing MIMO efficiency defined at the 95% Probability of Detection is evaluated for the two modes of operation at different frequencies and for different coverage cones. The 2-bitstream coverage pattern of the antenna for the two modes are plotted over the range of Angles-of-Arrival (AoA), by choosing fixed polarization (horizontal and vertical) for the incoming waves. The coverage pattern is significantly degraded for the 2-port mode, in particular in the middle of the band. © 2015 The Institute of Electronics, Information and Comm.
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| 7. |
- Mansouri Moghaddam, Sadegh, 1987, et al.
(författare)
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Designing a dual-polarized octave bandwidth bowtie antenna for a linear array
- 2016
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Ingår i: 2016 10th European Conference on Antennas and Propagation, EuCAP 2016. - 9788890701863 ; , s. Art. no. 7481892-
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Konferensbidrag (refereegranskat)abstract
- In this paper, we propose a linear array configuration for Random Line-of-Sight Over-The-Air testing set-up in anechoic chamber. For this aim, we use the self-grounded dual-polarized bowtie antenna as the element in the array. We present a new design of the bowtie to improve the array performance in terms of reflection coefficient and directivity. The new design has a simpler profile to manufacture. A good reflection coefficient performance has been achieved over the entire band of interest, i.e., 1.6-3GHz. The directivity of the array is almost constant for both polarizations over the entire frequency band.
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| 8. |
- Mansouri Moghaddam, Sadegh, 1987, et al.
(författare)
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Double broadband balun structure using CRLH TL for differential excitation of dual-polarized self-grounded bow-tie antenna
- 2015
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Ingår i: Progress in Electromagnetics Research Symposium. - 1559-9450 .- 1931-7360. ; 2015-January:2015, s. 1966-1970
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Konferensbidrag (refereegranskat)abstract
- A broadband compact balun comprising two composite right-left handed transmission lines (CRLH TL) is designed to excite a self-grounded bow-tie antenna. The design is based on a fractal shaped CRLH TL balun modified to the frequency band of interest. This balun consists of one +90° branch and three-90° branches to produce the desired 180° phase difference at the output. The simulated results show an amplitude imbalance of less than 1dB and a phase imbalance of less than 10°over most of the target bandwidth, i.e., 1.6-3 GHz. Two of the designed baluns were integrated with the bow-tie antenna in such a way that the feeding network could totally fit at the back of the antenna. The performance of the whole structure was also evaluated showing a return loss below-10 dB. The radiation pattern and the gain of the antenna with baluns are in good agreement with the ideal differential excitation, with gain degradation of only about 0.5 dB in the worst case.
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| 9. |
- Mansouri Moghaddam, Sadegh, 1987, et al.
(författare)
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Improvement of an octave bandwidth bowtie antenna design based on the analysis of a MIMO efficiency metric in random-LOS
- 2017
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Ingår i: Microwave and Optical Technology Letters. - : Wiley. - 1098-2760 .- 0895-2477. ; 59:6, s. 1229-1233
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Tidskriftsartikel (refereegranskat)abstract
- A multiple-input multiple-output (MIMO) efficiency metric based on the probability of detection (PoD) of data bitstreams is used to improve the design of a self-grounded dual-polarized wideband bowtie antenna over an octave bandwidth. The analysis is based on the ideal digital threshold receiver model for the Zero-Forcing algorithm. The random line-of-sight (Random-LOS) channel model with two orthogonal linearly polarized waves coming from the same angle-of-arrival is considered in the evaluation. The MIMO efficiency performance is presented along with the reflection coefficient, the directivity and the radiation patterns of the antennas. Corresponding spatial throughput coverage patterns based on 2-bitstream MIMO efficiency evaluated at the 95% PoD level are also provided. The loss of orthogonality as well as the power imbalance of the 2-bitstreams has been identified as the main reasons to MIMO efficiency performance degradation in Random-LOS.
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| 10. |
- Mansouri Moghaddam, Sadegh, 1987, et al.
(författare)
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Semi-omnidirectional dual-polarized wideband multiport antennas for MIMO applications in Random-LOS and RIMP
- 2017
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Ingår i: 2017 11th European Conference on Antennas and Propagation, EUCAP 2017. - 9788890701870 ; , s. 636-639
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Konferensbidrag (refereegranskat)abstract
- We present two configurations of multiport antennas for Multiple-input Multiple-output (MIMO) application. The configurations are comprised of three and four dual-polarized self-grounded bowtie antenna as the element, respectively. The MIMO performance of both antennas is evaluated in Random Line-of-Sight (Random-LOS) and Rich Isotropic Multipath (RIMP) channel models as two edge propagation environments. Both configurations provide 360° azimuth and 120° elevation angular coverage in Random-LOS and full sphere coverage in RIMP. Using digital threshold receiver model and Zero-Forcing receiver, the performances of both configurations are evaluated in terms of Probability of Detection (PoD) and MIMO multiplexing efficiency calculated at 95% PoD level. The simulated results show a good performance for both structures in two edge environments, which can be concluded as a good performance in a real life situation.
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