Practical uncertainty of pulse power measurements in Ka-band RCS instrumentation

The output level of pulsed radar transmitter and receiver test sets can be defined with spectrum analyzers and diode detectors. Modern analyzers, which have 10 MHz or wider resolution bandwidths and cover appropriate input frequency ranges, can be used in the Ka- and V-band radar domains for pulse widths above about 200 ns. A practical uncertainty of 2 dB is obtainable. External mixers seem to show larger-level discrepancies, up to 5 dB, and may give only 20 dB of dynamic range. Their conversion loss may vary by 8 dB over just 500 MHz. Diodes work at higher power levels, but rise-time definitions are complicated. Above -15 dBm input levels, we can get uncertainties comparable to spectrum analyzers, but the true dynamic range can be just 15 dB, and temperature effects may hamper outdoor trials. Below 200 ns pulse widths, radar-receiver test-generator level calibration remains very challenging in the millimeter-wave bands due to inadequate sensitivity, regardless of the measuring instrumentation.