An Ultra Broad-Band (200 kHz-26 GHz) High-Sensitivity Probe

The RF properties of a thin-film resistive strip in free space are derived using a transmission line analysis approach in conjunction with an appropriate equivalent circuit. The broad-band matching network for a properly chosen Schottky diode is then designed on the basis of this circuit model. Theoretical response, isotropic construction, and experimental results of the probe are presented. A 100-fold improvement in sensitivity over existing probes has been realized.