Wideband Transmissive Polarization Rotator with In-Band Notches Enabling Multiband Operation

A low-profile and wideband transmissive polarization rotator is proposed in this article. The wideband performance is accomplished by utilizing a curved bowtie resonator. The proposed wideband design exhibits a simulated bandwidth of 129.07% for at least 90% cross-transmission coefficient. The operating bandwidth is from 22.8 GHz to 105.8 GHz and the structure thickness is 0.082~lambda -{mathrm {max}} , where lambda -{mathrm {max}} is the free-space wavelength at the lowest operating frequency. A comparison with previously reported wideband polarization rotator designs is performed to highlight the notability of the proposed design regarding the wideband performance and structure thickness. In addition, in-band notches are utilized within the wide operating band to accomplish a transmissive polarization rotator with multiple operating bands. Single and double notches are employed to achieve polarization rotator designs with dual- and tri-band of operation, respectively. Moreover, the proposed multiband technique enables bandwidth adjustment. The prototype is fabricated and experimentally studied and is found to be highly correlated to the numerical estimation.