Design of frequency selective surfaces for a gyro-multiplier output system

This paper presents our on-going work on the development of an output system for a THz gyro-multiplier. The beam-wave interaction and frequency multiplication in the gyro-multiplier generate two high-order modes at two distinguished frequencies. To convert the high-order waveguide modes into quasi-Gaussian beams and separate the two frequencies, a quasi-optical mode converter (QMC) and a frequency selective surface (FSS) are combined in the designed output system. The QMC is used to convert both the high order modes into quasi-Gaussian beams, while the FSS is used to separate the two frequencies. This presentation focuses on the design, fabrication and testing of the required FSS.