Triple-band dual-sense circularly polarised planar monopole antenna

摘要

A simple and compact triple-band dual-sense circularly polarised (CP) microstrip line fed planar monopole antenna is presented here with ultra-wide impedance bandwidth. The proposed antenna comprised a slit-loaded semi-circular radiating patch and a stub-loaded modified ground plane. By properly embedding a slit into the patch and a stub into the modified ground plane, the proposed monopole structure radiates triple band CP in broadside direction. The overall size of the proposed antenna is 40 x 40 x 1.6 mm(3). The proposed antenna is capable of generating right hand CP wave in the lower and upper CP band, while left hand CP wave is generated by the middle CP band. The measured - 10 dB impedance bandwidth is 122% (2.74-11.32 GHz) and 3-dB axial ratio bandwidths for the triple bands are 41.55% (4.08-6.22 GHz), 17.03% (7.52-8.92 GHz) and 14.68% (9.34-10.82 GHz), respectively. The measured peak gains within three CP bands are 4.24, 4.02 and 3.78 dBic, respectively.