LOW-COST TOTAL POWER RADIOMETER USING CONVENTIONAL DTH ANTENNA

摘要

With the commercial availability of fast ADC/DAC, fast DSP processor, passive remote sensing systems are becoming popular in the sensing of fisheries, vegetation, and soil monitoring in agriculture remotely. Active remote sensors like radar are embedded within the smart vehicle and commercially available. In comparison, passive remote sensing using radiometers is less costly in comparison with radars, as radiometers use only broadband receivers without any transmission. With this motivation, this paper deals with the development of a low cost, microwave total power radiometer in the Ku-band frequency range. Here we present a prototype of a radiometer using readily available DTH dish antenna. Here we have utilized the same Low Noise Block (LNB) as connected with the commercial DTH antennas. It receives the RF signal over a frequency range of 10.7 GHz to 11.7 GHz. Inside the LNB, there was a Local Oscillator (LO) of 9.75 GHz, which is responsible to down-convert the incoming RF signal to intermediate frequencies (IF) from 950 MHz to 1950 MHz respectively. The IF signals are captured by the Keysight Spectrum Analyzer. The observed data is further processed through the LabView. The authors are able i) to design and implement a total power radiometer, ii) to sense a metal target, iii) to measure the thermal noise (Tisky ) in presence of Tiamb using NI data acquisition card and also using Keysight Spectrum Analyzer passively without any radio transmission.