A New Method of Interference Evaluation Between an Ultrawideband System and a Wireless LAN Using a Gigahertz Transverse Electromagnetic Cell

A new method of evaluating the interference to a wireless LAN with a built-in antenna using a gigahertz transverse electromagnetic (GTEM) cell is proposed. The GTEM cell can generate a wideband electromagnetic field from dc up to several gigahertz with a high spatial uniformity in the cell. This is advantageous for configuring a system for a victim receiver with a built-in antenna. Furthermore, the strength of the interfering electromagnetic field to be applied to the victim can be directly calculated from a given equivalent isotropically radiated power and propagation distance of the interfering signal in free space. It should also be noted that a GTEM has a conductive enclosed structure that is much smaller than typical anechoic rooms. As an example of use of the method, the evaluation of interference between an IEEE 802.11a wireless LAN and a direct-sequence spread-spectrum UWB was conducted. Investigations are further conducted on the effects of the UWB signal on the throughput of the victim wireless LAN system on the basis of bit error rate estimated with measurement results of the amplitude probability distribution of the UWB signal.