Simple current waveform probe for microwave amplifiers

A probe for sensing current waveforms in microstrip-based microwave power amplifiers is demonstrated. Its simple transfer function permits real-time current waveform displays using a sampling oscilloscope, without computer correction of the responses. Sample waveforms are presented for an active transmitting antenna, where the operating frequency is 2.3 GHz and harmonics up to the 5/sup th/ are correctly reproduced.