5 GHz MMIC optically controlled oscillator design from nonlinear modelling of microstrip photo-induced switching devices

Progress in the photoswitching device modelling is reviewed. These passive structures working thanks to the photoconductivity effects, present efficient ON/OFF ratios and suitable phase shift. Insertion losses are the most inconvenient of this component. For 50 /spl mu/m length gap on GaAs substrate, insertion losses vary from -45 to -25 dB in the frequency range 0.1 to 40 GHz under 130 mW power illumination. More performances with this device are obtained when it is used to optically controlled MMIC devices. A novel oscillator according to this procedure is presented. Harmonic balance code simulation results of this optoelectronic circuit reveal a microwave signal generation at a frequency of 4.985 GHz and a power -7.2 dBm. This system, which works only when a suitable optical signal is applied at the top of the circuit, is under test.