Radiation from picosecond photoconductors in microstrip transmission lines

Signals radiated in the microstrip autocorrelation circuit are investigated using ion-bombarded InP photoconductors. A model and empirical data are presented which suggest that this circuit radiatively couples to itself, giving rise to what appears to be a "slow" signal in the autocorrelation data. It is demonstrated that with a judicious choice of electrode geometry, a subpicosecond signal radiated by the photoconducting gap can be separated from the slower signal radiated by the microstrip electrodes.