Quad-Band Polarization-Insensitive Millimeter-Wave Frequency Selective Surface for Remote Sensing

A novel millimeter-wave frequency selective surface (FSS) is presented for demultiplexing four atmospheric remote sensing bands with varying bandwidth (3-20 GHz) and frequency separation (50-195 GHz). The unit cell (670 μm × 670 μm) is a circular metal mesh loaded with a monopole integrated concentric ring on a 175-μm-thick quartz substrate designed to reject 50-60 GHz (B1), 87-91 GHz (B2), and 148-151 GHz (B3), and transmit 175-195 GHz (B4) for transverse electric (TE) and transverse magnetic (TM) polarizations at oblique incidence (25°-35 °). Transmission response of the cascaded FSS measured using a continuous-wave terahertz source showed insertion loss of 15 dB and higher in the reflection windows (B1, B2, and B3) and less than 0.5 dB in the transmission window (B4) for TE and TM polarizations at 30° incident angle.