Design and cold testing of a compact TE/sub 01//spl deg/ to TE/sup /spl square///sub 20/ mode converter

In this paper, we discuss a new compact converter, which converts the TE/sub 01/ circular mode into the TE/sub 20/ rectangular mode. Compared to the Marie converter, the new device has a significantly shorter length and is, therefore, more suitable for use in evacuated waveguide systems. Both the design efforts and the experimental testing of the prototype are described. Based on computer simulations, this converter has a center frequency of 17.15 GHz, and the predicted power transfer between the desired modes is 99.9%. Results from the low-power testing of the prototype indicate that when the TE/sub 20/ output mode is split into two equal parts (each in the TE/sub 10/ rectangular mode), the power transferred to each arm of the split differs by less than 0.15 dB over a 200-MHz bandwidth. This is the first experimental study of a converter based on this design. A high-power version of this device is now being fabricated for use under high vacuum conditions.