Sub-THz Four-Way Waveguide Power Combiner With Low Insertion Loss

A four-way waveguide power divider has been developed in sub-THz band. The waveguide power divider was achieved with the improved H-plane T-junction structure. By tuning the depth and width at the junction of the waveguide, the input impendence was matched and the two-way output power amplitude and phase were at the same level. The four-way power divider was realized by the concatenation of two same T-junction at the two output ports. A sub-THz four-way passive power combiner is designed, fabricated and measured. The measure results show that the measured insertion loss of the fabricated four-way passive power combiner is less than 1.2 dB whereas the input return loss is greater than 14.8 dB from 97.5 to 101.7 GHz. Experiments on the sub-THz four-way passive power combiner show that a minimum insertion loss of 1 dB has been achieved at about 99.5 GHz. The measured minimum insertion loss of the waveguide power divider is half of the insertion loss for the entire passive power combiner (0.5 dB), which corresponds to a power-combining efficiency of 89 %. The measured results agree with the simulated ones closely.