Amplification and calibration for miniature E-field probes

The amplification and signal-conditioning system for a miniature nonperturbing RF E-field probe is described. A simple calibration procedure using an X-band slotted waveguide is presented. It requires less power and space than conventional techniques requiring antenna measurements in an anechoic chamber. Measurement results demonstrate relatively small field perturbation due to the probe; and a region in the waveguide where the field is relatively uniform and suitable for calibration. Calibration accuracy is further established by comparing results with those obtained from antenna measurements in an anechoic chamber. To establish the calibration technique, the probe-amplification system is analyzed, leading to a gain equation relating the output voltage and measured field intensity, which is experimentally verified