An integrated waveguide-to-MMIC (monolithic microwave integrated circuit) chip operating in the 300-GHz range is designed to operate well on highpermittivity semiconductor substrates typical for an MMIC amplifier, and allows a wider MMIC substrate to be used, enabling integration with larger MMICs (power amplifiers). The waveguide-to- CBCPW (conductor-backed coplanar waveguide) transition topology is based on an integrated dipole placed in the Eplane of the waveguide module. It demonstrates low loss and good impedance matching. Measurement and simulation demonstrate that the loss of the transition and waveguide loss is less than 1-dB over a 340-to-380-GHz bandwidth. A transition is inserted along the propagation direction of the waveguide. This transition uses a planar dipole aligned with the maximum E-field of the TE10 waveguide mode as an inter face between the waveguide and the MMIC. Mode conversion between the coplanar striplines (CPS) that feed the dipole and the CBCPW transmission line is accomplished using a simple air-bridge structure. The bottom side ground plane is truncated at the same reference as the top-side ground plane, leaving the end of the MMIC suspended in air.

This work was done by Kevin M. Leong, William R. Deal, Vesna Radisic, Xiaobing Mei, Jansen Uyeda, and Richard Lai of Northrop Grumman Corporation, and Lorene A. Samoska, King Man Fung, and Todd C. Gaier of Caltech for NASA’s Jet Propulsion Laboratory. The work was sponsored under the DARPA SWIFT program and the contributors would like to acknowledge the suppor t of Dr. Mark Rosker (DARPA) and Dr. H. Alfred Hung (Army Research Laboratory). For more infor mation, download the Technical Support Package (free white paper) at under the Semi - conductors & ICs category. NPO-46237

This Brief includes a Technical Support Package (TSP).
Waveguide Transition for Submillimeter-Wave MMICs

(reference NPO-46237) is currently available for download from the TSP library.

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This article first appeared in the December, 2009 issue of NASA Tech Briefs Magazine.

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