Design and Development of Multi-band and Ultra-wideband Antennas and Circuits for Ice and Snow Radar Measurements

Remote sensing based on radar technology has been successfully used for several decades as an effective tool of scientific discovery. A particular application of radar remote sensing instruments is the systematic monitoring of ice and snow masses in both hemispheres of the Earth. The operating requirements of these instruments are driven by factors such as science requirements and platform constraints, often necessitating the development of custom electronic components to enable the desired radar functionality.

This work focuses on component development and trade studies for two multichannel radar systems. First, this thesis presents the design and implementation of two dual-polarized ultra-wideband antennas for a ground-based dual-band ice penetrating radar. The first antenna operates at UHF (600–900 MHz) while the second antenna operates at VHF (140–215 MHz). Each antenna element is composed of two orthogonal octagon-shaped dipoles, two inter-locked printed circuit baluns and an impedance matching network for each polarization. Prototype of each band shows a VSWR of less than 2:1 at both polarizations over a fractional bandwidth exceeding 40%. The antennas developed offer cross-polarization isolation larger than 30 dB, an E-plane 3-dB beamwidth of 69 degrees, and a gain of at least 4 dBi with a variation of ± 1 dB across the bandwidth. This design with high power handling in mind also allows for straightforward adjustment of the antenna dimensions to meet other bandwidth constrains. It is being used as the basis for an airborne system.

Next, this work documents design details and measured performance of an improved and integrated x16 frequency multiplier system for an airborne snow-probing radar. This sub-system produces a 40 – 56 GHz linear frequency sweep from a 2.5 – 3.5 GHz chirp and mixes it down to the 2 – 18 GHz range.  The resulting chirp is used for transmission and analog de-chirping of the receive signal. The initial prototype developed through this work provided a higher level of integration and wider fractional bandwidth (>135%) compared to earlier versions implemented with the same frequency plan and a path to guide future realizations.

Lastly, this work documents a series of trade studies on antenna array configurations for both radar systems using electromagnetic simulation tools and measurements.