Feed structure for ultra-wide spectrum short-pulse electric-field standard device

The quality of the ultra-wide spectrum short-pulse electric field generated by standard devices is extremely dependent on the field structure at the feed. We studied the discontinuity of coaxial feed. The results show that the length of cone pin is important for impedance matching and obtaining good performance of time domain response. Equivalent circuit analysis, simulation and experiment were performed to analyze the response of the feed. The voltage reflectivity of the feed could be reduced to 4% by adjusting the cone pin when incident pulse width ranges from 0.3 ns to 1.5 ns, while the pin length is held at 1.0 mm. Furthermore, a D-dot sensor was used to measure the field pulse and the result shows a high-fidelity replica of the incident pulse waveform in the time window of the cone.