High Quality Factor, Thin-Film, Electrically Tunable Varactors and Filters

Toyon Research Corporation proposes to design, fabricate, and characterize a high-Q, gallium nitride (GaN) varactor diode for a tunable bandpass filter application. GaN has not received much attention in this area and Toyon feels that it is worth an investigation. GaN is used for several new electronic and optoelectronic devices so the manufacturing base and reliability of the material is strong. Toyon has completed simulations of a device with a 4:1 capacitance range, a minimum predicted Q of 212 at 2 GHz, and a bias range of 9.5 - 35 V. The elevated bias range will strengthen the IP3 performance of the filter. Toyon will design and simulate a 5-pole filter tuned from 1.3 - 2.7 GHz that uses five of the varactors. All of the varactors will tune in parallel so that only a single tuning voltage is required. Toyon will procure GaN wafers from a commercial vendor and fabricate devices at the UCSB Nanofabrication Facility. The epitaxy and devices will be characterized in one of UCSB's mm-wave labs. The Nanofabrication Facility and mm-wave lab are available to commercial users at an hourly rate.