Accurate and Robust CW-LFM Radar Sensor: Transceiver Front-End Design and Implementation

This paper outlines the design and implementation of a continuous-wave linear-frequency-modulated sensor for short-range radar applications. Low-cost technologies have been selected to implement the sensor. It was integrated on a 0.127-mm-thin ceramic substrate using the miniature hybrid microwave integrated circuit technology. Two 16-dBi gain 8 × 2 patch antenna arrays are implemented in the transmitter and receiver modules. The receiver is a six-port homodyne quadrature down-converter. The integrated power detectors are fabricated using HSCH-9161 Schottky diodes. The complete sensor, in the metallic fixture, measures 35 × 45 mm. The performance of the sensor to detect a target range and velocity is validated using system simulations and measurement systems on a test bench. System simulations use computer models based on S-parameter measurement results. Measurements show that an accuracy of ± 16.23μm can be achieved with the sensor over a range of 15 cm. To precisely measure the six-port radar accuracy, due to our RF laboratory capabilities, this result is obtained by changing the electrical length, instead of varying the physical distance.