Wideband High-Gain Dual-Band CP Antenna with Integrated Polarizer

A novel aperture-shared dual-band circularly polarized (CP) antenna, offering wideband and high gain performance, is proposed in this study. This design represents the first attempt to integrate a polarizer into a dual-functional surface (PIDFS), enabling the co-design of a CP reflectarray (RA) and a CP Fabry Perot cavity (FPC) antenna. The antenna operates by providing wave reflection with polarization rotation at higher frequency bands, facilitating the implementation of a millimeter-wave CP reflectarray. Simultaneously, it functions as a CP partially reflective surface (PRS) for a high-gain FPC antenna designed for lower frequency spectra. The proposed PIDFS ensures wide bandwidth for both the RA and FPC bands, thanks to its low-Q-factor characteristic. To validate the design, a prototype of the aperture-shared dual-band CP antenna, operating at 7 and 30 GHz bands, was designed, fabricated, and measured. The measured results closely align with the simulated ones, achieving 3-dB gain bandwidths of 8.5% and 23.7% with peak gains of 17.3 and 20.5 dBic over the two bands, respectively. This innovative design holds great potential for future communication systems that require high integration, wideband coverage, and high CP gain.