| 1. |
- Prasad, Sathyaveer, 1978-, et al.
(författare)
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Mean Effective Gain Measurements of Mobile Phones using the Telia Scattered Field Measurement Method
- 2007
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Ingår i: RFMTC07. - Stockholm : KTH. ; , s. 7-
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In this paper, the measurement procedure for estimation of mobile phone antenna performance is presented. This is achieved by considering the Mean Effective Gain (MEG) relative to half-wavelength dipole antenna as the figure of merit. MEG of 13 commercially available mobile phones is measured using the Telia Scattered Field (TSFM) Method in one channel at each of the GSM900 and DCS1800 bands. The measurements of these handsets are carried out in Rayleigh fading environment, characterized by the XPR obtained from the propagation measurements. The statistics of the measured envelope distribution have been fitted to Rayleigh, Rice and Weibull distributions with corresponding goodness of fit analysis. Further, the investigation focuses on the variation of MEG with the surrounding environment of propagation and also with the position of the mobile phone.
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| 2. |
- Halim, Humam, et al.
(författare)
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Evaluation of a Near Field Scanner for TRP and Radiation Pattern Measurements of GSM Mobile Phones
- 2009
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Ingår i: 3rd European Conference on Antennas and Propagation, 2009. EuCAP 2009.. - Berlin : EUCAP2009. - 9781424447534 - 9783000245732 ; , s. 2207-2211
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In this paper a new tool for estimation of the radio performance of terminal antennas in terms of Total Radiated Power, TRP is tested and evaluated. The tool is known as Lab Express and is developed by the Canadian company EMSCAN. The results from measurements performed with the Lab Express are compared with of the radiation patterns and total radiated power (TRP) estimates, measured with a CTIA approved Satimo SG24 chamber. The TRP and radiation pattern measurements are performed on 10 commercially available mobile phones at GSM 900 and GSM 1800 frequency bands. The dependency of the measured TRP on the positioning of the mobile phone on EMSCAN is also tested. Our results indicate that the TRP measured with Lab Express is well correlated with the results obtained from the Satimo SG24 chamber even though the Lab Express equipment seem to over estimate the TRP with on average about 4dB at 900MHz and about 1.3dB at 1800MHz.
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| 3. |
- Prasad, Sathyaveer, 1978-, et al.
(författare)
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Estimation of the Rician K-factor in Reverberation Chambers for Improved Repeatability in Terminal Antenna Measurements
- 2008
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Ingår i: 30th Annual Symposium of the Antenna Measurement Techniques Association (AMTA). - Boston, Mass. : AMTA.
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Konferensbidrag (refereegranskat)abstract
- The in-network performance of the mobile phone depends highly on the terminal antennas. Their performance may reduce the coverage and the capacity of the whole network. Hence, an antenna measurement method that accurately emulates the in-network radio environment is much desired. The reverberation, or mode-stirred, chamber is a cavity resonator with a high Q factor used for testing the performance of terminals and terminal antennas in a controlled field environment. In order to create a homogeneous field inside the chamber, emulating an isotropic multipath environment, mode stirrers are used. The Rician K-factor is a statistical parameter that describes the field distribution in the chamber and is defined as the ratio of the unstirred to stirred field components in the chamber. This K-factor varies from zero to infinity. In order to be able to accurately repeat a measurement performed in a reverberation chamber it is, hence, of greatest importance to accurately determine the Rician K-factor from said measurements. In this paper, a statistical model for the electromagnetic fields in reverberation chamber is reviewed for a Line of Sight (LOS) environment. An Estimator of the Rician K-factor is derived and its accuracy is verified.
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| 4. |
- Prasad, Sathyaveer, 1978-, et al.
(författare)
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EVALUATION OF THE TELIA SCATTERED FIELD MEASUREMENT METHOD FOR ESTIMATION OF IN-NETWORK PERFORMANCE OF MOBILE TERMINAL ANTENNAS
- 2007
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Ingår i: 29th Annual Symposium of the Antenna Measurement Techniques Association (AMTA 2007). - St.Louis,USA : AMTA 2007.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In this paper we present and evaluate a method for estimation of in-network performance of mobile terminal antennas developed by the Swedish telecom operator Telia. The Telia Scattered Field Measurement (TSFM) Method is intended to give a better estimate of the performance of the mobile terminal antenna as in an in-network fading scenario. The parameter measured from the TSFM method is referred to as the Scattered Field Measurement Gain, SFMG, i.e. the Mean Effective Gain, MEG, measured relative to a half wave dipole antenna. MEG includes the radiation pattern of the mobile terminal antenna as well as an estimate of polarization and directional losses that occur due to the propagation environment. In this study it is found that the TSFM method provides a good measure of the in-network performance of the mobile terminal antenna. Furthermore, it is shown that the SFMG measured with this method is found to be well correlated with the Total Radiated Power Gain, TRPG, or radiation efficiency. This suggests that the Total Radiated Power, TRP, may be a good measure of the in-network performance of mobile terminal antennas if measured with proper adjustment to the antenna and propagation channel mismatch.
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| 5. |
- Prasad, Sathyaveer, 1978-
(författare)
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Over-the-Air Performance Estimation of Wireless Device Antennas
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis work presents studies on the available measurement methods for estimating the over-the-air (OTA) performance of wireless device antennas. This thesis is divided into two parts. The first part is focused on studies of single-input single-output (SISO) OTA measurement methods and the second part is focused on studies of multiple-input multiple-output (MIMO) OTA measurement methods.In the first part, the three methods for estimating the up-link radio performance of mobile phone antennas are evaluated, including the “EMSCAN Lab Express” planar near-field system, the “Telia Scattered Field Measurement method (TSFM),” and the “Bluetest” reverberation chamber. These methods are compared to the standard reference anechoic chamber methods.Each method is experimentally evaluated by measuring the total radiated power from a number of commercially available mobile phones in addition to comparing the measurements to the results from a standard reference system. The comparison is performed statistically using simple regression analysis. For the reverberation chamber (RC), applying simple physical and statistical modeling extends the analysis. In particular, a maximum likelihood (ML) estimator for the Rician K−factor is derived, followed by both statistical and experimental evaluations.Based on the results of the first part of this thesis, it can be concluded that the EMSCAN Lab Express planar near-field method overestimates the uplink performance of mobile phones, consequently introducing an error. The up-link performance of mobile phones estimated using the TSFM method agrees with the reference method but suffers from problems such as extensive measurement time and poor repeatability. The Bluetest RC method estimates the uplink performance of mobile phones well. However, the Rician K−factor computed from the ML estimator is found to be greater than zero, indicating an inadequacy in the propagation environment inside the RC.In the second part, the anechoic chamber-multipath simulator (MPS) and the RC-very large MIMO (VLM) OTA testing methods are studied.In the MPS method, the impact of scattering within the MPS array antennas on the Rician fading statistics is addressed by performing simulations and measurements based on the proposed MPS scattering model and the derived far-field criteria. The results of the investigation suggest that to minimize the impact of scattering, a large MPS system must be designed, although it will result in higher costs. In turn, the costs can be lowered by miniaturizing the MPS system, which can be achieved by following the derived far-field (Fraunhofer distance) criteria. Thus, miniaturization will also allow the measurement uncertainties to be restricted at an acceptable level.In the VLM OTA testing method, the study is based on very large virtual uniform linear array measurements and focuses on the multidimensional characterization of the channel transfer function and the channel impulse response of the reverberation chamber. The results of this study suggest that the reverberation chamber can be used to emulate the more realistic channels for testing the VLM antenna systems.
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