Folding the Feeding Network of a Millimeter-Wave Circularly Polarized Printed Antenna Array

This paper discusses the effects of folding the feeding network of printed antenna arrays operating in the Ka-band range of the spectrum. More specifically, the impact of single- and double-folded topologies on the radiation behavior of a 10-element antenna array is investigated and analyzed herein. Such impact is assessed in terms of impedance matching, circularly polarized realized gain, and axial ratio bandwidth. The proposed double-folded design features an impedance bandwidth between 26 GHz and 34 GHz while preserving circular polarization between 28.9 GHz and 30 GHz. The proposed design also achieves a maximum realized gain of 13.6 dBic, a half-power beamwidth of 11⁰, and a cross-polarization level of 14.31 dB along the direction of maximum radiation.