Practical considerations in pulse-echo radar for short range sensing

In this paper, we present the principle of operation, design, and testing of a pulse echo radar unit that utilizes the properties of short helical antennas. Data was captured for targets approaching the radar at three different controlled velocities, three different target sizes, and three radar range gate settings. These data reveal the expected Doppler frequency as well as a second anomalous frequency. The effects of multipath signals, separated transmit and receive antennas, and direct antenna coupling are used to explain this anomalous frequency. These effects are mathematically simulated, and the results compare favorably with the test data.