| 1. |
- Glazunov, Andres Alayon, 1969, et al.
(författare)
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Impact of the Spatial User Distribution on the Coverage Antenna Pattern of Maximum Ratio Combining in Random Line-Of-Sight
- 2015
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Ingår i: 9th European Conference on Antennas and Propagation, EuCAP 2015, Lisbon, Portugal, 13-17 May 2015. - 9788890701856
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Konferensbidrag (refereegranskat)abstract
- In this paper we investigate the impact of the spatial user distribution on the Maximum Ratio Combining (MRC) of the output signals from an ideal 4-port antenna. The antenna consists of four elementary Huygens sources operating in Random Line-Of-Sight (RLOS). The antenna is assumed to be wall-mounted. Two specific scenarios for the user distribution are considered, i.e., the 3D hemisphere and a rectangular prism emulating a corridor or a rectangular room. We present simulation results in terms of the cumulative distribution functions corresponding to the resulting polarisation and pattern diversity of 1-bitstream and the corresponding coverage radiation pattern of the 4-port antenna system. We also show that there is an antenna arrangement that maximizes the diversity gain that will be different for different spatial distributions of users.
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| 2. |
- Schilliger Kildal, Madeleine, 1987, et al.
(författare)
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Evaluation of a Random Line-of-Sight Over-the-Air Measurement Setup at 28 GHz
- 2021
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Ingår i: IEEE Transactions on Antennas and Propagation. - 0018-926X .- 1558-2221. ; 69:8, s. 5008-5020
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Tidskriftsartikel (refereegranskat)abstract
- OTA measurement techniques have, and will continue to have, a key role in evaluating the performance of modern antennas and wireless devices. The new random line-of-sight (random-LOS) measurement setup, offers the evaluation of the OTA performance of different types of devices, for example car antennas and small wireless devices in the random-LOS environment. A plane wave is synthesized in the test zone of the OTA setup, where the far-field of a radio base station can be emulated. We present measurements and simulations of the random-LOS OTA measurement setup employing a reflector antenna, with a dual polarized linear array feed, operating at the 28 GHz band. An analysis of the power and phase field distributions in a cylinder and a circular test zone are presented. The computed standard deviation of the power distribution is approximately 1 dB within a circular test zone, with a diameter of 0.3 m. The standard deviation of the phase, within the same test zone, is less than 15 °. The radiation patterns of a horn antenna have been measured in the random-LOS measurement setup and shown a good agreement with the theoretical values.
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| 3. |
- Schilliger Kildal, Madeleine, 1987, et al.
(författare)
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Verification of the Random Line-of-Sight Measurement Setup at 1.5-3 GHz including MIMO Throughput Measurements of a Complete Vehicle
- 2020
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Ingår i: IEEE Transactions on Vehicular Technology. - 0018-9545 .- 1939-9359. ; 69:11, s. 13165-13179
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Tidskriftsartikel (refereegranskat)abstract
- The performance evaluation of wireless systems is crucial for the development of future systems with more connected devices. It is essential to have an easy and relevant method for ensuring the wireless communication performance of the devices. We have recently developed a new random line-of-sight (random-LOS) measurement system for evaluating the communication performance of wireless devices, e.g., transceivers and antennas installed on a vehicle. In the measurement system, a plane wave is generated in the test zone emulating the far-field wave transmitted from a radio base station. In this paper we present both numerical simulations and actual experimental results of the random-LOS over-the-air (OTA) measurement setup operating in the 1.5-3 GHz band. The measurement accuracy is determined by the field variations within the test zone, where a smaller variation gives better measurement accuracy. In this paper the achieved accuracy expressed in terms of standard deviation (STD) was evaluated to be approximately 1 dB of the power within a cylindrical test zone of height 0.4 m and diameter 2 m. The active multiple-input multiple-output (MIMO) performance of antenna systems installed on an actual vehicle was measured and evaluated using the presented setup. A comparison to a theoretical zero forcing (ZF) receiver is also presented.
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| 4. |
- Alibakhshikenari, Mohammad, et al.
(författare)
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Dual-Polarized Highly Folded Bowtie Antenna with Slotted Self-Grounded Structure for Sub-6 GHz 5G Applications
- 2022
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Ingår i: IEEE Transactions on Antennas and Propagation. - 0018-926X .- 1558-2221. ; 70:4, s. 3028-3033
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, a novel dual-polarized highly-folded self-grounded Bowtie antenna that is excited through I-shaped slots is proposed for applications in sub-6GHz 5G multiple-input-multiple-output (MIMO) antenna systems. The antenna consists of two pairs of folded radiation petals whose base is embedded in a double layer of FR-4 substrate with a common ground-plane which is sandwiched between the two substrate layers. The ground-plane is defected with two I-shaped slots located under the radiation elements. Each pair of radiation elements are excited through a microstrip line on the top layer with RF signal that is 180° out of phase with respect to each other. The RF signal is coupled to the pair of feedlines on the top layer through the I-shaped slots from the two microstrip feedlines on the underside of the second substrate. The proposed feed mechanism gets rid of the otherwise bulky balun. The Bowtie antenna is a compact solution with dimensions of 32 32 33.8 mm3. Measured results have verified that the antenna operates over a frequency range of 3.1–5 GHz and exhibits an average gain and antenna efficiency in the vertical and horizontal polarizations of 7.5 dBi and 82.6%, respectively.
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| 5. |
- Alibakhshikenari, Mohammad, et al.
(författare)
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Wideband Sub-6 GHz Self-Grounded Bow-Tie Antenna with New Feeding Mechanism for 5G Communication Systems
- 2019
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Ingår i: 13th European Conference on Antennas and Propagation, EuCAP 2019. ; March 2019
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Konferensbidrag (refereegranskat)abstract
- This paper presents a self-grounded directional Bow-Tie antenna with a novel feed structure for sub-6 GHz applications in 5G communication systems covering 3.35-4.4 GHz. The antenna consists of two petal shaped metal structures that are fed by a bend microstrip line with an out-of-phase excitation. The petals are anchored on a common ground-plane. The feed mechanism used to excite the petals is by EM coupling from a single open-circuited microstrip line implemented behind the ground-plane. The coupling of EM energy from the input microstrip line to the feed microstrip line is controlled via an I-shaped slot printed on the ground-plane. The proposed antenna offers good impedance matching across its operating frequency range with VSWR<2 and exhibits an average gain of 20 dBi for an 8×8 element antenna array.
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| 6. |
- Chen, Lei, 1982, et al.
(författare)
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A Method of Reducing Mutual Coupling Using an Extra Coupling Path
- 2019
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Ingår i: 13th European Conference on Antennas and Propagation, EuCAP 2019.
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Konferensbidrag (refereegranskat)abstract
- A method of reducing mutual coupling for a large-scale array with the wideband and beam steering characteristics is proposed in this work. An extra coupling path is intentionally introduced to reduce the mutual coupling among adjacent radiating elements. A millimeter wave array is used to verify the proposed method. The simulation results show that the mutual coupling between adjacent elements can be reduced to below -15 dB over the band of 19-39.5 GHz and this concept is viable even for the beam steering angle range of ±45°.
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| 7. |
- 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 ; 2017-January
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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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| 8. |
- Glazunov, Andres Alayon, 1969, et al.
(författare)
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Zero-forcing MIMO efficiency in random line-of-sight
- 2016
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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
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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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| 9. |
- Khanal, Prabhat, 1993, et al.
(författare)
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A Contactless Feeding Network Design Using MetaCoax Coupler
- 2022
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Ingår i: 2022 IEEE International Symposium on Antennas and Propagation and USNC-URSI Radio Science Meeting, AP-S/URSI 2022 - Proceedings. ; , s. 1760-1761
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Konferensbidrag (refereegranskat)abstract
- A novel contactless capacitively coupled PCB-to-PCB coupler is proposed in this paper. The coupler is used to couple a 2×2 element circularly polarized antenna array PCB to its feeding layer PCB and connectors. The simulated results of the antenna array alone and the antenna array with the couplers matches well, indicating the good performance of the contactless feeding network. The antenna array with the couplers has 18% bandwidth and a maximum gain of 11.15 dBi, which is only 4% and 0.13 dBi smaller than that of the directly excited antenna array.
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| 10. |
- 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. ; 2018:CP741
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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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