Dual band/wide band waveguide polarizer

The design of a wide band iris or corrugated polarizer covering two separate bands is discussed here. By making use of thick irises with close spacing, a compact polarizer with fewer irises and a shorter electrical length can be designed with high performance characteristics. Such a polarizer was built and tested. The agreement between predictions and measurements is excellent. Over a continuous band with high-to-low frequency ratio greater than 1.3:1, the polarizer has a return loss below -35 dB and a cross-polar isolation greater than 35 dB. Over the two separated bands of interest, its return loss is lower than -40 dB and cross-polar isolation is better than 40 dB.