A Low-Profile Cavity-Backed Dual-Polarized Spiral Antenna Array

A low-profile cavity-backed dual-polarized printed spiral antenna array is presented. This spiral array is composed of four center-fed Archimedean spiral antennas printed on FR4 substrate backed by a low-profile cavity without absorbing material. The dual polarization is generated using monopolarized spirals in an alternating configuration right-hand circularly polarized (RHCP) and left-hand circularly polarized (LHCP). These spirals are connected allowing the current to flow from the excited spirals arms into the arms of the neighboring ones. The proposed spiral array provides unidirectional beam while being dual-polarized (LHCP or RHCP) for a wide bandwidth. The dual polarization of the proposed spiral array is extended to low frequencies, and the gain varies up to 13 dBi in the antenna bandwidth. The antenna array performances are presented and validated using electromagnetic simulations and radiation pattern measurements.