A new type of ka-band waveguide-based power-combining structures

In this paper, a power-amplifier (PA) module at ka-band presented using a new type of broad-band spatial power-combining system. The combiner can accommodate more monolithic microwave integrated-circuit (MMIC) PA on limited microstrip space in ka-band waveguide structure with good return losses, and heat can dissipated into aluminum carrier quickly. This combiner is based on a slotline- to-microstrip transition structure, which also serves as a four-way power combiner. The proposed 2×2 combining structure combined by vertical stacking inside the waveguide was analyzed and optimized by finite-element-method (FEM) simulations and experiments. This paper demonstrates the potential of the proposed power combiner for more MMIC(PA) accepted in this type of high-power amplification at millimeter wave frequencies.