Silicon integrated waveguide technology for mm-wave frequency scanning array

We present a Bi-CMOS compatible technology based on potassium hydroxide wet etching and employing only two lithography masks for the integration of silicon filled waveguides with continuous metallic walls. The realized waveguides present a trapezoidal cross-section and provide very low losses (0.2 dB/mm at 100 GHz) and cross-talk. A coplanar to waveguide transition based on resonating slots is described, achieving 0.87 dB of insertion loss at 100 GHz. Finally, to showcase the capability of this technology to enable mm-wave system integration, a frequency scanning array at 93 GHz based on uniform offset slots is integrated. The array provides a beam steering capability of 92° within a 20.8 GHz band and a maximum half power beam-width of 9°.