| 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. |
- Kvarnstrand, John, et al.
(författare)
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Comparison of live person test to head and hand phantom test in reverberation chamber
- 2016
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Ingår i: 2016 10th European Conference on Antennas and Propagation (EuCAP).
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Konferensbidrag (refereegranskat)abstract
- The Total Radiated Power of a cell phone was measured in a reverberation chamber with a head and hand phantom and compared to live person testing of 5 test subjects who held device in similar grip as the phantom. Repeatability in tests was examined for the phantom and for the live person test subjects. The method demonstrated can be used to evaluate mobile devices handled by live persons. It can also be used to validate that a phantom is a good representation of live persons.
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| 3. |
- Glazunov, Andres Alayon, 1969, et al.
(författare)
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Devising a Horizontal Chamber Array for Automotive OTA Tests in Random Line-Of-Sight
- 2016
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Ingår i: International Symposium on Antennas and Propagation (ISAP), Hobart, Australia, 9-12 November, 2015. ; , s. Art. no. 7447285-
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Konferensbidrag (refereegranskat)abstract
- In this paper we propose an approach to design a horizontal array antenna to reduce the uncertainty of reference measurements in Random Line-Of-Sight Over-The-Air testing in anechoic chambers. The main focus is on wireless communications testing to and from automotive vehicles. The proposed procedure allows to determine the size, the spacing and the number of elements of a horizontal array antenna resulting in an absolute error less than 1 dB. The analysis is based on presenting the output of the ideal digital threshold receiver model of the device under test as a Probability of Detection curve.
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| 4. |
- 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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| 5. |
- Schilliger Kildal, Madeleine, 1987, et al.
(författare)
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Initial Measured OTA Throughput of 4G LTE Communication to Cars with Roof-Mounted Antennas in 2D Random-LOS
- 2016
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Ingår i: International Symposium on Antennas and Propagation (ISAP), Hobart, Australia, 9-12 November, 2015. ; , s. Article no 7447419-
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Konferensbidrag (refereegranskat)abstract
- We present initial Over-The-Air (OTA) throughput measurements of an LTE device in a Volvo XC90 car with roof-mounted antennas. The measurements were performed ina semi-anechoic chamber and only in the horizontal plane. The throughput results are presented as a probability of detection (PoD) in 2D Random Line-Of-Sight (Random-LOS) with fixed polarization of the antenna at the base station side. Two carmounted antennas were measured: a wideband two-port sharkfin type antenna in SISO and SIMO receive diversity-mode, and a narrowband monopole antenna. The PoD curves clearly show the expected performance improvements due to the antenna diversity.In addition, the Random-LOS measurements made it possible to discover potential for improvements of the tested antennas.
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| 6. |
- Schilliger Kildal, Madeleine, 1987, et al.
(författare)
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Investigation of mode stirring with plate on platform in a reverberation chamber
- 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
- The accuracy of the reverberation chamber has been investigated when mode stirring is performed with a plate placed on a rotatable platform, i.e., plate-on-platform stirring. The accuracy and scanning volume of the platform plate are then compared to the original mode stirring plates that are moving alongside two walls. The results are also compared to physical theoretical models. The mode stirring with a plate on the platform provides STD of the measurements that are a factor 2 worse than with the original plate and platform stirring of the chamber. Still, this is good enough for accurate measurements above 2 GHz, provided the AUT is also located on the platform.
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| 7. |
- Schilliger Kildal, Madeleine, 1987, et al.
(författare)
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Measured LTE throughput for SISO, SIMO and MIMO in Polarization-Random-LOS
- 2016
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Ingår i: 2016 IEEE International Symposium on Antennas and Propagation (APSURSI). - 9781509028863 ; , s. 323-324
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Konferensbidrag (refereegranskat)abstract
- LTE throughput measurements in a Random Line-of-Sight (Random-LOS) setup have been performed. The effect of polarization-randomness on the level of detection threshold of one or two bitstreams has been investigated. Good agreement is shown between theory and experiments for the SISO, SIMO and MIMO cases.
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| 8. |
- Schilliger Kildal, Madeleine, 1987, et al.
(författare)
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Measured probabilities of detection for 1- and 2 bitstreams of 2-port car-roof antenna in RIMP and Random-LOS
- 2016
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Ingår i: 2016 10th European Conference on Antennas and Propagation (EuCAP). - 9788890701863
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Konferensbidrag (refereegranskat)abstract
- Autonomous cars will in a near future drive around in cities and on highways. Antennas will then be needed to secure the wireless connection to these cars. To be able to test the antennas we have defined two edge environments: the Random Line-of-Sight (LOS) and the Rich Isotropic Multipath (RIMP). This paper shows a throughput performance comparison between measurements and simulations of a car-roof (shark-fin) antenna mounted on a ground plane in both of these environments. The comparison is done for both one and two bitstreams in a 2×2 MIMO system. The analysis is based on probability of detection (PoD) curves representing the throughput performance with digital threshold receivers.
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| 9. |
- 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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| 10. |
- Glazunov, Andres Alayon, 1969, et al.
(författare)
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Impact of Azimuthal Antenna Pattern Sampling and Variation on Throughput Measurements
- 2019
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Ingår i: 2019 IEEE Conference on Antenna Measurements & Applications (CAMA). - 9781728123967 ; , s. 167-170
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Konferensbidrag (refereegranskat)abstract
- Presented is a numerical study of the impact of the antenna pattern sampling resolution on the accuracy of Over-The-Air (OTA) throughput measurements. More specifically, a Line-Of-Sight (Random-LOS) testing scenario is addressed. The communication throughput is evaluated as the Probability of Detection (PoD) of a single bitstream based on the ideal digital threshold receiver model. The maximum deviation of throughput efficiency is computed as a function of the azimuthal sampling resolution for various generic antenna gain patterns. The coefficient of variation of the antenna gain pattern is introduced to evaluate the impact of the azimuthal sampling. The presented approach can be used to define the sampling resolution of the throughput performance of a device under test in Random-LOS OTA.
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