High-Power In-Line Waveguide to Coaxial Adapter

We present the design of and experiments with a high-power in-line transition between the WR340 rectangular waveguide and the 7/8” EIA coaxial line. The adapter is intended for operation in the 2.45-GHz ISM band, with CW power up to 2 kW. The design is based on electromagnetic simulation. Our measurements demonstrated the adapter's inband return loss typically exceeding 30 dB. The adapter successfully sustained tests with input CW power of 3 kW.