Design of On-Board Impedance Matching Circuit for Millimeter-Wave Presystem

A millimeter-wave presystem is a system whose RF part is composed of a set of RF modules of element circuits connected via waveguides instead of being composed of an MMIC. Introducing the millimeter-wave presystem enables to shorten overall development period because the millimeter-wave presystem can be built at an early stage of MMIC development and therefore the application development can be started earlier by using the presystem. To build the millimeter-wave presystem, on-board impedance matching circuits are essential to suppress return loss in each RF module. This paper describes the design of an on-board impedance matching circuit for 79GHz millimeterwave presystem. To ensure simulation accuracy, the bonding wire, PCB, and IC in the RF module were separately modeled to fit with measured data. The on-board impedance matching circuit was designed by using these models. Owing to these accurate models, the fabricated impedance matching circuit achieved a return loss smaller than -10dB.