Compact four-way quasi-rectangular cavity power combiner with high isolation and high power-combining efficiency

摘要

A compact four-way quasi-rectangular cavity power combiner with high isolation and high power-combining efficiency is presented. The quasi-rectangular cavity is employed to realize both impedance transformation and mode conversion. The isolation circuit based on microstrip line technique is utilized to realize high isolation. Besides, a T-junction is established as a transition from coaxial to microstrip to realize the energy transmission between the cavity and the isolation circuit. The presented power combiner is designed, fabricated, and measured. The actual assembled device is 0.74 lambda x 0.74 lambda x 0.28 lambda (lambda is waveguide wavelength). The measured results show the return loss of the power-combining port is greater than 20 dB from 7.84 to 10.88 GHz (36% fractional bandwidth). The measured insertion loss is about 0.4 dB, and the power-combining efficiency is about 90%. The measured isolation of adjacent and opposite ports is greater than 20 dB in operating frequency band.