Compact coaxial-waveguide four-way power divider with low insertion loss and high output isolation

Abstract

ABSTRACT This paper presents a compact coaxial-waveguide four-way power divider with high efficiency, low insertion loss, and high isolation. To improve power capacity and facilitate fabrication, the power divider adopts a square coaxial-waveguide structure. Furthermore, to enhance isolation performance, a star-shape isolation microstrip circuit is utilized, connected with four resistors. The measurements demonstrate that the return loss of the sum port is greater than 20 dB from 7.8 GHz to 10 GHz, while the return loss of the output ports is greater than 20 dB from 7.25 to 9.18 GHz. The insertion loss is approximately 0.3 ± 0.1 dB and the isolation is greater than 23 dB from 7 GHz to 10 GHz. The combining efficiency is over 92%. Additionally, the power divider has a compact size of approximately 0.8 λ × 0.8 λ × 0.19 λ for the central frequency of 8.5 GHz.