Feedhorn Synthesis Using a Parameterized Aperture Field Distribution

In this letter, we present an improved method for synthesizing smooth-profiled horns. A direct connection between the mode compositions and far-field parameters was established by utilizing a parameterized aperture field distribution and the field decomposition method. It speeds up the optimization process by a factor of 5. The requirements for the aperture field to maintain a constant directivity were studied based on the method. A feedhorn was optimized for a W-band gyro-TWA with a 0.7 dB variation of the directivity within a bandwidth of 10%.

I. Introduction

Gyro-devices based on cyclotron maser instability can generate high-power radiation at millimeter and sub-millimeter wave frequencies. The gyrotron travelling-wave amplifiers (gyro-TWAs) possess unique features such as controllable output power and phase, high power levels, and a balanced performance in terms of gain and bandwidth. They are attractive for diverse applications, including plasma diagnostics, radar systems, remote sensing, dynamic nuclear polarization (DNP), and electron spin resonance (ESR) spectroscopy [1], [2], [3].