Compact wideband omnidirectional UHF antenna for TV white space cognitive radio application

This paper presents design and analysis of a compact wideband omnidirectional antenna for application in TV white space cognitive radio. The proposed antenna mainly consists of a monopole, a pair of parasitic elements, and a brief impedance matching network, all etched on an FR4 substrate. To obtain physical insight, an equivalent circuit is modelled and analysed to reveal the contribution of each part of the antenna to its bandwidth enhancement. Performance of the antenna is evaluated by simulations, and then further validated by experiments. Experimental results show that the antenna has an impedance bandwidth (voltage standing wave ratio less than 2) ranging from 460 MHz to 870 MHz, as well as omnidirectional radiation patterns in H-plane through the whole band.