Design of stacked circular/quasi-elliptical patch array for broadband CP applications

This paper presents a design of circularly polarised 4- element planar subarray composed of low axial-ratio stacked patch elements in X-band. The wideband circular polarisation is excited by using stacked circular disc and quasi-elliptical patch that printed oil a superstrate with low dielectric constant (epsilon(r) = 2.2) and a high di electric constant (epsilon(r) = 6.15) material as the substrate, respectively, The propose element exhibits low mutual coupling in two principle planes that is comparable to a single-layer circular patch antenna. To determine the optimal element spacing inside the sabarray, a pair of microstrip-line fed elements was considered and arranged in four scenarios. Low sidelobe levels and 2-dB axial-ratio bandwidth of 19.5%, in addition to a boresight axial-ratio of 0. 15 dB are achieved Variations in gain and axial ratio other than boresight (theta not equal 0) in azimuth plane are also examined.