X‐band compact coaxial power combiner for high‐power applications

Abstract

A four-way power combiner with small cross-sectional size and high power capacity is investigated in this study. The design is based on the cascaded structure of three rectangular hybrid rings and one coaxial-to-waveguide transition. The combiner consists of coaxial and waveguide structures to ensure high power capacity. The compact cross-sectional size (0.71 λ × 0.74 λ at the centre frequency) is achieved by employing transverse electric magnetic (TEM)-mode coaxial line structures. A prototype power combiner is fabricated and tested to verify the design results. It has been demonstrated that the proposed power combiner has a power capacity of 16 kW. The return loss is better than 25 dB, isolation degree higher than 27 dB, and amplitude imbalance within 0.16 dB limits in the operating band 8–9 GHz, validated with both simulations and experiments. The proposed structure is suitable for kW-level power combining and it can also be implemented in planar forms for a wider range of applications.