Modular Frequency Multiplier and Filters for the NASA Global Hawk Snow Radar

Abstract

This thesis documents the process of adapting the 2-18 GHz Snow Radar to meet the requirements for operation on manned and unmanned platforms from 700 ft to 70,000 ft. The primary focus of this work is the development of an improved microwave chirp generator implemented with frequency multipliers. The miniaturized design presented here reduces reflections in the chain, size, and weight compared to current large and heavy connectorized chain. Each stage is implemented by a drop-in type modular design operating at microwave and millimeter wavelengths; realized with commercial surface-mount integrated-circuits, wire-bondable chips, and custom filters. Another focus of this thesis is the development of different distributed element band-pass filters used in the frequency multiplier like edge-coupled band pass filters on alumina substrate and interdigital cavity filters developed in-house. Overall, the measured results of the modular frequency multiplier and filters match with the expected responses from original design and co-simulation outputs.