Terahertz Four-Way Out-of-Phase Waveguide Power Combiner With Low Insertion Loss

A terahertz four-way out-of-phase waveguide power combiner has been proposed and analyzed in this paper. The input return loss of the circuit is improved greatly by the power combiner through the metal matching square column in the center of the circuit node, and the four output ports are reversed in equal amplitude. A simple equivalent circuit model for this power-combining structure has been developed. To verify the validity of the proposed structure, a four-way power combiner structure with the center frequency of 145 GHz has been designed and fabricated with conventional machining. The measured input return loss of the circuit is greater than 16 dB from 130 to 162 GHz. And the insertion loss is less than 0.5 dB from 140 to 160 GHz, which corresponds to a power-combining efficiency of 90%.