An online tunable TE11 dual-circular polarizer applied for modern high-power radar system

Abstract

Circular polarizers have essential applications in modern radar and communication systems. However, an online tunable wideband dual-circular polarizer with a power capability of more than 150 kW in the Ku band has not been reported yet, and it has recently become a fundamental problem for developing some high-power radar systems. This paper has designed an overmoded waveguide operating in the TE11 mode with a non-contact cutting-off choke to imply a high power capability. A high-precision stepping motor is used to control the rotation of an elliptical waveguide remotely, and then, the left-hand and right-hand circular polarizations can be switched online. The dual-circular polarizer has been fitted on a 150 kW gyro-TWT high-power test system, and the experimental results show a tremendous high-power capability. The microwave leakage caused by the non-contact gap is reduced to less than −35 dB. The polarization bandwidth exceeds 2.5 GHz in the Ku band, and the axial ratio is better than 1.3 dB. This design concept provides a reference for future high-power radar systems.