Reconfigurable UWB filtennas with sharp WLAN dual bandnotch

Abstract

This paper presents the design and results of a reconfigurable ultra-wideband (UWB) 3.1–10.6 GHz filtenna with sharp dual bandnotch for WLAN 5.25 GHz and 5.8 GHz bands. A design for a bandstop filter is first proposed. Reconfigurability of the filter is achieved by the implementation of Graphene based switches and PIN diodes within the proposed filter. The filter was simulated, fabricated and measured for switch OFF and ON states. The simulated and measurement results are in good agreement with each other. The results for a switch OFF case show no bandnotch in the passband of the filter. While for a switch ON case, dual bandnotch have been obtained at a measured insertion loss rejection of 30 dB. The filter is then integrated with an UWB antenna. The resulting filtenna is simulated, fabricated and measured. Obtained simulation and measurements results of both switches in OFF and ON states have been presented to validate the accuracy of the proposed structures. On comparison, the obtained results of PIN diodes match those of the Graphene based switches. The results of the filtenna with both switches in OFF state show an entire bandpass response from 3.1–10.9 GHz with no bandnotch present. In ON state, the results show that sharp rejections at 5.3 GHz and 5.8 GHz are achieved at a measured return loss of 2.5 dB.