22/43 GHz low-insertion-loss dual-polarized multi-layer bandpass frequency selective surfaces for millimeter astronomy

Abstract We design a frequency selective surface (FSS) capable of transmitting K-band and reflecting Q-band radio waves. The equivalent circuit approach assists the distribution of multi-layer FSS to achieve a third-order bandpass response with an incident angle of less than 30°. The unit structure consists of three metal layers embedded with two dielectric substrates. Especially, the FSS provides a 3 dB transmission bandwidth range from 18.6 to 26.7 GHz with a maximum measured insertion loss of 0.61 dB. Hence the proposed polarization-insensitive FSS with low insertion loss can be applied in the observation system of millimeter astronomy.