Highly Miniaturized On-Chip 180° Hybrid Employing Periodic Ground Strip Structure for Application to Silicon RFIC

Abstract

A highly miniaturized on-chip 180° hybrid employing periodic ground strip structure (PGSS) was realized on a silicon radio frequency integrated circuit. The PGSS was placed at the interface between SiO2 film and silicon substrate, and it was electrically connected to top-side ground planes through the contacts. Owing to the short wavelength characteristic of the transmission line employing the PGSS, the on-chip 180° hybrid was highly miniaturized. Concretely, the on-chip 180° hybrid exhibited good radio frequency performances from 37 GHz to 55 GHz, and it was 0.325 mm2, which is 19.3% of a conventional 180° hybrid. The miniaturization technique proposed in this work can be also used in other fields including compound semiconducting devices, such as high electron mobility transistors, diamond field effect transistors, and light emitting diodes.