Silicon-Based IC-Waveguide Integration for Compact and High-Efficiency mm-Wave Spatial Power Combiners

A novel and compact millimeter-wave (mm-Wave) spatial power combiner is developed integrating a silicon-based integrated circuit (IC) in a metal waveguide (WG). As an initial step toward integrating a silicon-based active IC in a WG, a passive back-to-back (B2B) transition incorporating a four-way spatial power splitter and combiner is realized at $E$ -band (71–86 GHz). In contrast to existing solutions, the proposed design considers power splitting and combining using a low-loss wireless transition between the IC and the WG. The proposed B2B structure comprises an IC implemented using the Institute for High Performance Microelectronics (IHP’s) 0.13- $\mu \text{m}$ SiGe BiCMOS technology integrated into the $H$ -plane of a WG. The IC is postprocessed and assembled in the WG prototype. The measured prototype shows a return loss better than 13 dB, an average insertion loss of 1.7 dB for a single transition, and a fractional bandwidth of 26.4% (69–90 GHz).