A wideband design of rectangular TE 10 to circular TE 01 mode transducer

A design of wideband rectangular TE 10 to circular TE01 mode transducer is proposed. The circular TE 01 mode wave is synthesized by connecting four rectangular waveguides to a circular waveguide in a rotationally symmetric fashion. No other mode waves parasitize in the transducer due to its rotational structure, which ensures high purity of the circular TE 01 mode. In addition, the transducer has no frequency dependent structure and no slot-coupling effect is involved. Therefore, the mode transducer can operate in a wideband frequency range with low loss. The transducer is fabricated and the measurement results well agree with the simulation. The return loss is less than -10 dB and the transmission loss is less than 1 dB in a wideband range from 21.5 to 28.3 GHz. The size of the entire transducer is within the volume of 53.2 mm in diameter and 58.6 mm in length, which meets the demand of miniaturization design.