Compact Digital Receiver Development for Radar Based Remote Sensing

This paper is the first of a series of publications that discusses the design and implementation of an inexpensive, nearly all-digital FPGA-based radar receiver which can be used in a variety of applications including single/dual-polarization weather radar, sidelobe cancellation, a subarray module for a digital beam-forming phased-array radar, and other applications where a compact, low-power, low-cost receiver is needed. The design of the receiver includes a minimal analog RF front-end followed by an analog-to-digital converter utilizing a bandpass sampling technique which allows the FPGA to produce baseband in-phase (I) and quadrature (Q) signals without the use of multipliers or look-up tables. The primary difference between the efforts of others and the efforts here is the use of single or multiple frequency channels in the receiver. The efforts of others have had applications in multi-channel military radars and in software defined radios that receive a variety of information. Here, only one frequency channel is needed for environmental observations, which provides a unique impetus to facilitate low-cost, low-power designs by leveraging software defined radio techniques.