UWB crossed exponentially tapered slot antenna with WLAN band rejection

Abstract

Ultrawide-band (UWB) is a new technology that transmits very low energy levels broadband pulses allowing for short-range high-bandwidth communications. In some environments, UWB systems require the inclusion of band-rejection filters to avoid the possible interference from pre- established wireless local area networks (WLAN), allocated from 5.15 GHz to 5.825 GHz. Recently, the required band rejection is being incorporated directly at the antenna to avoid the addition of band rejection filters in the UWB system module. This constitutes an additional challenge for UWB antenna design. In fact, UWB radio antennas are required to be compact, low-profile and low-cost while presenting good pulse-preserving performance, impedance match, polarization, gain and radiation pattern stability over the UWB band. The addition of the band-notch can be produced through some modification of the full-band solution. Planar printed technology has been used for a plethora of full-band UWB antenna configurations, mostly based on dipole/monopole configurations and on slot-based antennas. One such antenna, a very compact printed planar slot-based UWB antenna has been previously presented. It is a balanced configuration that exhibits excellent spatial polarization and radiation pattern stability versus frequency. It is referred as the crossed exponentially tapered slot antenna (XETS). The present paper proposes and evaluates by simulation a modification of the previous layout to produce the required WLAN band-rejection. Results show that the new configuration remains complaint with the FCC requirements and corroborate the potential of the proposed antenna for UWB applications.