Circularly polarised integrated filtering antenna with polarisation reconfigurability

Yunlong Lu, Yi Wang, Steven Gao, Changzhou Hua, Taijun Liu

Research output: Contribution to journalArticlepeer-review


A new design of circularly polarised integrated filtering antennas with reconfigurable polarisation is proposed in this study. Two phase-reconfigurable coupled λ/2-resonator pairs have been used to feed the antenna and generate the second-order filtering response and the circular polarisation (CP) simultaneously. By switching the PIN diodes inserted in the feeding network, a phase difference of +90° or -90° can be realised at the outputs of the feeding network. This renders the antenna's capability of switching its polarisation from right-hand CP (RHCP) to left-hand CP (LHCP) or vice versa. The use of the coupled-resonator pairs significantly improves the frequency selectivity and out-of-band rejection of the CP antenna. To the best of the authors' knowledge, this is the first report of a multifunctional antenna which has integrated filtering performance, CP, and polarisation reconfigurability. To verify the design concept, a reconfigurable CP antenna operating at 2.45 GHz is implemented. The simulated and measured results agree well with each other and show that the antenna has an impedance bandwidth of 4.5%, an average in-band gain of 6.0 dBic (LHCP)/6.1 dBic (RHCP), out-of-band rejections of >10.8 dB, and 3 dB axial ratio bandwidth of 9.4%/10.5%.
Original languageEnglish
Pages (from-to)2247-2252
Number of pages6
JournalIET Microwaves, Antennas and Propagation
Issue number15
Early online date13 Oct 2017
Publication statusPublished - 25 Dec 2017


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