Zietsman, Christian Frederick. Theory, Design and Implementation of an IF Cancellation Module for use in a Stepped Frequency Continuous Wave Ground Penetrating Radar. MSc Dissertation. Department of Electrical Engineering, University of Cape Town, 2004.
A device has been designed that cancels the leakage signal between the transmit and receive antenna in a Stepped Frequency Continuous Wave Ground Penetrating Radar. The front end of the radar operates at high signal levels and, as a result, a large signal is coupled directly from the transmit to the receive antenna. This signal uses a significant part of the dynamic range of the data-capturing device, an analogue-to-digital converter (ADC). The objective of this cancellation is thus to increase the effective instantaneous dynamic range of the radar system.
Simulations show that 10-bit amplitude and phase resolution in the digital cancellation circuit would achieve maximum cancellation in the presence of phase noise and other sources of error. This result is confirmed when the hardware is tested. The device was constructed and operates as intended. Tests show that cancellation exceeding 53dBm is possible through careful calibration. It was concluded that the device could successfully be integrated into the SFCWGPR and that it would achieve an increase in the instantaneous dynamic range.