Correction of IQ mismatch for a particle tracking radar

Abstract

For a better understanding of granular flow problems such as silo blockage, avalanche triggering, mixing and segregation, it is essential to have a `microscopic' view of individual particles. In order to cope with the difficulty arising from the opacity of granular materials, such as sands, powders and grains, a small scale bi-static radar system operating at $10$\,GHz (X-band) was recently introduced to trace a sub-centimeter particle in three dimensions. Similar to a moving target indicator radar, the relative movement of the tracer with respect to each of the three receiving antennae is obtained via comparing the phase shift of the electromagnetic wave traveling through the target area with an IQ-Mixer. From the azimuth and tilt angles of the receiving antennae obtained in the calibration, the target trajectory in a three-dimensional Cartesian system is reconstructed. Using a free-falling sphere as a test case, we discuss the accuracy of this radar system and possible ways to enhance it by IQ mismatch corrections.