Radar receiver calibration in pulsing mode

This paper analyzes the calibration of the W-band Wyoming Cloud Radar receivers, specifically the analog logarithmic amplifiers/detectors (log-detectors), operating in pulsed mode. Two MITEQ log-detectors were tested; one with 22 MHz and a second with 40 MHz bandwidth, both operating at 120 MHz central frequency. It was found that both detector models exhibited some change in behavior when detected 250 ns pulses (puled mode, PM) compared to continuous wave (CW) signals. The 120/22 detector changed the slope of its logarithmic transfer function by as much as 10% while the 120/40 amplifier became more non-linear, deviating from a linear transfer function up to an additional 1 dB. It was therefore concluded that the receivers should be calibrated in pulsed or continuous wave mode, depending on the application, and that a non-linear receiver calibration lookup table is the best approach to minimize the errors for the full dynamic range of analog logarithmic detectors