Wideband 1-bit Filtenna-to-Filtenna Cross-Polarization Converter Using Multimode Resonance

A new filtenna-to-filtenna (FA-T-FA) cross-polarization converter (CPC) is proposed using multimode resonance (MMR) techniques. The CPC unit cell comprises two identical filtennas and two matching vias. Each filtenna consists of a magneto-electric (ME) dipole antenna and a ground plane with four L-shaped resonators. The matching vias not only match the two filtennas but also enable a 1-bit phase resolution of the CPC. First, modes of the filtennas and the matching vias are investigated independently. Afterward, the filtennas are arranged back-to-back and orthogonal, and connected using the matching vias, forming an FA-T-FA CPC. This configuration allows linearly polarized waves to be transformed into their orthogonal counterparts upon passing through the CPC. Four transmission modes of the CPC are generated, leading to a −3 dB fractional bandwidth of 17.9%, a polarization conversion ratio (PCR) of 99%, and an energy conversion ratio (ECR) of 94% in the passband. The lower and upper rejection bands of the CPC benefit from the ME dipole antennas and the L-shaped resonators, respectively. Moreover, the proposed CPC can maintain a stable response under the incidence angle of 55°. To validate its efficacy, the FA-T-FA CPC is fabricated and measured. Simulation and measurement results demonstrate a reasonable agreement, affirming the practical viability of the proposed CPC. With its wide passband, high selectivity, high PCR and ECR, 1-bit phase resolution, and good angular stability, the FA-T-FA CPC emerges as a promising candidate for high-performance and multifunctional metasurfaces.