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Bluetest's 2 nd generation reverberation chamber (0.8 m × 1.0 m × 1.6 m), set-up for measuring radiation efficiency and input mismatch of phone antenna, and set-up for measuring telephone communication power (TCP), respectively
Source publication
The paper gives a summary of the work that has been performed in the antenna group at Chalmers University of Technology on measuring antennas for mobile phones in reverberation chambers. Reverberation chambers were originally developed for EMC measurements. We have shown that they can also be used to measure performance of antennas that are designe...
Contexts in source publication
Context 1
... two measurement set-ups are illustrated in Figure 1. The instruments and the five step motors of the chamber are controlled from a PC (not shown), which also gathers all results and processes them. ...
Citations
... Mode-stirred chambers (MSCs) have since about a decade come to widespread use for antenna characterization and tests of wireless terminals [1][2][3][4][5]. Lately, much research has focused on how to make MSCs more flexible and versatile. ...
Mode-stirred chambers provide an excellent tool for antenna characterization. Recent research has focused on making the mode-stirred chamber technique more versatile. One result of these efforts is the sample selection technique, by which a subset of data with specific properties is extracted from a measured set of raw data. This paper presents how to apply the sample selection technique to measurements of the correlation coefficient in dual antenna measurements, for example, for diversity or MIMO applications. Theoretical background and useful mathematical relations are presented. The application is verified through measurements.
... Reverberation chambers (RC) have been widely used in measurements of electromagnetic compatibility such as radiated-immunity testing of wireless devices [1] [2]. This measurement environment provides a statistically isotropic, randomly polarized, uniform field across a large proportion of the chamber volume caused by a stirrer revolution [3]. ...
In this paper we present the influence of the load position, represented by a metallic cube, inside the uniform zone of a compact reverberation chamber when it is placed asymmetrically to the chamber's wall. The measurement standard test of the uniform zone requires an empty chamber. The measurements of the chamber statistical electrical field uniformity are made accordingly the IEC61004-21 standard. Unfortunately, no guarantee of the field uniformity is assured when the equipment is positioned inside.
Reverberation chambers (RC) are widely used for measuring antenna performance and parameters for MIMO systems. RCs for mobile phone antenna tests are often specially designed for this purpose. The lowest frequency of operation of an RC is decided by its size. With a trend of lower frequency bands being allocated for mobile phones, the minimum size of RCs for mobile phone antenna tests increases, and is approaching the size of a normal room. At the same time, many large shielded rooms are already in use for various electrical measurements. In this paper, a standard shielded room designed for EMC testing is used as an RC for mobile phone antenna tests. To complete the RC, a large mode stirrer is built. The fact that the room is also used for other tests requires a detachable, foldable, and lightweight stirrer design. Therefore, metal meshes are evaluated for the design of the mode stirrer. The performance of the used room is verified by standard tests for RCs, and it is verified that it is possible to measure antennas from about 400 MHz up to 4 GHz with good accuracy. The size of the room also enables measurements including humans carrying mobile phones or body area networks.
The diversity performances of the wireless devices operating in a multipath propagation environment are usually presented in terms of correlation coefficient, diversity gain and effective diversity gain. These parameters can be measured in reverberation chamber. This paper presents some active measurements of antenna diversity performances on a small wireless terminal in several realistic environments. The measurements were performed in the WiMax band, i.e. at 3.5 GHz, in a reverberation chamber where the channel is statistically uniform, in a real indoor propagation channel, and in an outdoor-to-indoor environment. The diversity performances are evaluated by using a specific test-bed constituted by an arbitrary signal generator and two radio-frequency digitizers. The effectiveness of diversity is presented in terms of effective diversity gain, signal to noise ratio, bit error rate and frame error rate. © 2010 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2010.
The accuracy in reverberation chamber measurements relies on the chamber setup being able to generate a large number of independent measurement samples. Simple models for the number of independent samples with mechanical stirring and frequency stirring are presented, and also with several stirring techniques combined. The models are verified through measurements.
In this paper we present the influence of the load position, represented by a metallic cube, inside the uniform zone of a compact reverberation chamber when it is placed asymmetrically to the chamber's wall. The measurement standard test of the uniform zone requires an empty chamber. The measurements of the chamber statistical electrical field uniformity are made accordingly the IEC61004-21 standard. Unfortunately, no guarantee of the field uniformity is assured when the equipment is positioned inside.
