A Monolithic, Dual Channel, DC to 20GHz SPDT

This paper describes the design and evaluation of a Single Pole Double Throw (SPDT) switch IC covering DC to 20GHz. Two SPDTs are realised on each die to give a dual channel part for use in systems where accurate gain and phase matching between channels is vital. The switch was fabricated on Triquint Semiconductor Texas’ 0.25μm PHEMT process and has a measured insertion loss of less than 1dB to 10GHz and less than 1.6dB to 20GHz. The input and output return losses are greater than 14dB to 20GHz and the 1dB compression point is +27dBm. Introduction The primary application for the switch design was a dual channel receiver, requiring amplitude and phase matching between channels. For this reason two SPDTs were fabricated on each IC. The functionality of the IC is depicted in Figure 1. Although the two SPDTs switch together in this application, the facility for independent control of each has been included as it increases the versatility of the IC in terms of its suitability for re-use in other applications.