A simple dual-tone calibration of diode detectors

Abstract

A new dual-tone method to linearize diode detectors is proposed, in which two closely spaced CW carriers with equal amplitudes are fed into the diode detector to be calibrated. It is found that the output waveform of the detector is a distorted sinusoidal wave of the frequency difference between the two carriers. The deviation from the square-law response can be found from the distorted signal which is attributed to the detector through a simple iterative calculation. Measurement performed at 40 GHz has shown an error within 0.2 dB over a 40 dB dynamic range.<>