Development of a compact UWB MIMO antenna with WLAN band rejection

Abstract

Ultra Wide Band (UWB) technology has become attractive since the U.S. Federal Communications Commission allocated the (3.1-10.6) GHz frequency band for commercial UWB systems, it has become a favorable technology in the wireless communication area. UWB has promising applications in shortrange, high-data-rate transmission, medical imaging etc. Another challenge faced by these systems is multipath fading which can severely degrade the transmission quality. The use of multiple-input multiple output (MIMO) and array technology is an effective solution to mitigate this problem and improve the channel capacity and quality of wireless link. Issues like Multi path effect and reduction in BER are catered with the help of MIMO. This technique ensures high data rate. Therefore, a MIMO antenna operating in the UWB is key technology for next generation. The transmission capacity and reliability of a system can be improved by using diversity techniques without increasing the bandwidth and power. Although UWB is unlicensed band, there is interference due to coexisting narrow frequency bands. To protect WLAN frequency band from interference notch is added which act as filter. An improved model is proposed to reduce isolation between different antennas which occurs because of neighboring antennas. As a result return losses are increased which are also catered.UWB also introduces interference on other bands which is an important issue to be tackled. For these problems a notch is added to avoid these loopholes.