Designing an omnidirectional horizontally polarized circular patch antenna implementing unequal open‐circuited stubs

Abstract

A novel method of designing an omnidirectional horizontally polarized (OHP) patch antenna with omnidirectionality in the H‐plane is proposed in this letter. The three pairs of unequal arch slots with three open radial slots are etched on the ground, which is equivalent to three pairs of open‐circuited unequal stubs that excite the TM1.5,1 patch mode and produce two resonance frequencies with circulating in‐phase current on the patch and the ground. Additionally, three pairs of open‐circuited unequal stubs are generated to enhance bandwidth and generate extra resonance frequencies by sequentially printing unequal arch and open radial slots on the top patch. The proposed antenna's 10 dB impedance bandwidth, including all resonance frequencies of TM1.5,1 patch mode, is 10.20%, covering the 2.326–2.576 GHz Wi‐Fi band. The patch and ground diameter are 0.31λ0 and 0.387λ0, respectively, with a real gain of 1.84–1.98 dBi over the operating band, and a gain variation is within 1.3 dB in the H‐plane at two measured resonance frequencies.