Summary
International Symposium on Antennas and Propagation
2008
Session Number:3C20
Session:
Number:3C20-3
Comparison of Measurement Accuracy and Time of TRP and TIS in Reverberation and Anechoic Chambers
David Cheng, Wenlie Liang, Kevin Chen, Tommy Rau, Magnus Franzen, Mats Andersson,
pp.-
Publication Date:2008/10/27
Online ISSN:2188-5079
Summary:
The market for wireless technology is growing at a tremendous rate. Not only is the number of products within different market segments, e.g. mobile phones and WLAN equipment growing, but a large number of new types of wireless products are being introduced every year and also expected to experience rapid growth, for example RFID tags, TV game controllers like the Wii remote (Bluetooth), and home 3G base stations. The number of mobile phone users has passed 2 billion and will within a few years time pass 3 billion. About 1 billion new mobile phones are estimated to be sold in 2009 [1]. Most of these new products use small antennas. The Total Radiated Power (TRP) and Total Isotropic Sensitivity (TIS) of these devices have a direct influence on coverage, battery life time and bit rate in the up and down link. The TRP and TIS performance is very hard to estimate with software but relatively easy to measure. This is mainly due to the fact that small antennas are usually integrated in a chassis containing materials that absorb radiation or in different ways disturb the antenna function that are hard to model accurately. In a mobile phone there is furthermore a number of antennas that all affect each other. For small antennas the most important parameter to optimize is its antenna efficiency, i.e. the parameter that directly influences how much of the transmitter power is radiated into space, or how much of the radiation incident on the antenna reach the receiver. Since most of the small antennas must have high efficiency over a number of frequency channels and sometimes over several frequency bands, there is a need for a large number of measurements both during development and evaluation of wireless products. The faster a company can optimize the antennas in its wireless products, the faster the products can be released on the market to increase the competitiveness of the company. The traditional way of measuring antennas in anechoic chambers, i.e. without any reflections, is very good for large antennas that normally are used in a Line-Of-Sight (LOS) environment, but is a slow and unsuitable way to measure small antennas that normally are used in an environment with a lot of reflections, i.e. indoors or in an urban environment. Such an environment is much easier to simulate in a reverberation chamber. The reverberation chamber also have the advantage that it can be made much smaller and that the measurements are performed much faster than in an anechoic chamber. This paper will describe TRP and TIS measurements in Bluetest's High Performance (HP) reverberation chamber and give comparison to measurements of the same wireless devices in a CTIA approved anechoic chamber. It will be shown that the accuracy of the Bluetest chamber is similar to the CTIA approved anechoic chamber and that the measuerment times for TRP and TIS are between 3 - 20 times faster depending on type of test and communication protocol.