A QUASI-OPTICAL ISOLATOR

A nonferrite X-band quasi-optical isolator is presented, The isolator consists of six cascaded printed gratings loaded with lumped elements and exhibits less than 2-dB insertion loss, The isolator is designed f or protection and stabilization of quasi-optical amplifiers. A linearl y polarized output wave from a quasi-optical amplifier becomes circula rly polarized in the isolator, which in this case serves as a linear-t o-circular polarization converter as well. Isolation of 9 and 19 dB wa s measured for the co- and cross-polarized waves, respectively.