A novel digital intermediate frequency module for hyperspectral microwave radiometers based on the parallel fast Fourier transform algorithm

Abstract

Microwave radiometers, possessing all-day and all-weather operational capabilities, are extensively utilized in the exploration of planetary atmospheres and surfaces. The potential of the hyperspectral detection technology to enhance the precision and resolution of microwave radiometer detection has made it a crucial research focus. This paper introduces an intermediate frequency (IF) module for hyperspectral microwave radiometers. The IF module is constructed with two 6.4 gigabit samples per second sampling-rate analog-to-digital converter (ADC) chips and a Xilinx Virtex-7 field programmable gate array. By implementing a parallel fast Fourier transform algorithm and a pipeline architecture, the IF module can efficiently process all ADC sampling data in real-time, generating 512 channels of output for each ADC. The test results, including linearity, sensitivity, and flatness, are presented and thoroughly analyzed for the IF module. Furthermore, the module is interfaced with the radio frequency front-end of the microwave radiometer to measure hot and cold calibration sources and assess its sensitivity. When combined with a suitable front-end receiver, the IF module can form a radiometer system suitable for various applications of microwave remote sensing.