I-Q imbalance correction of microwave displacement sensors

Microwave displacement sensors are becoming increasingly popular as vital sign detectors and structural vibration detectors. Until now there is not any method known for calibrating them that does not require accessing the electronic board by inserting and probing test signals or does not require cumbersome equipment that is able to provide large linear displacements. Hence, proposed is a calibration method for I-Q correction that makes use only of an external mechanical oscillator (a metallic bar fixed at an edge). As a test device, a low-quality X-band transceiver with a strong imbalance has been used. The calibrated sensor is compared successfully with a high-performance seismic accelerometer.