Dual-Polarized Coupled Sectorial Loop Antennas for UWB Applications

In this letter, we present two compact dual-polarized UWB antennas based on the coupled sectorial loops antenna (CSLA) concept. The first antenna is a directional dual-polarized cavity-backed asymmetric CSLA for radar and communications applications. The antenna has the added ad vantage of easily controllable gain compared to conventional dual-polarized antennas. The second antenna design is a planar CSLA in a crossed dipole configuration that offers both polarization and pattern diversities. Its dimensions are 0.44λ_m × 0.44λ_m, where λ_m is the wavelength at the lowest operating frequency. These dimensions are about 20% higher than those of the original CSLA, but with the advantage of providing an extra polarization. This antenna is fabricated with an integrated balun feed and measured. The measurements and the simulations agree well and show good matching over more than two octaves of bandwidth and isolation better than 25 dB between the two polarization ports.