High-frequency Broadband Multi-throw Pin Switch Study

PIN Diode switch is a kind of widely used microwave semiconductor control device. High frequency,broadband,multi through switch are the places where design difficulties lie. Accurate simulation of switch circuit is needed in PIN switch design, while limited by assembling techniques, serial resonance and channel inter-coupling exist in the common joint that bring a lot of difficulties for simulation. 2-Dementions simulation software can not establish accurate circuit mode for PIN diode switch which gives simulation error, and it costs much more time with 3-Dementation simulation software, which is not applicable in practice for PIN switch design. A few causes which affect the specifications of PIN switches are analyzed here and a simplified model is proposed with 2Demention-3Demention hybrid simulation and optimization for circuit. The measuring results show high similarity with simulation outcome on a wide band (8-18GHz) SP8T PIN switch with the model.Being the fact that PIN switch tends to handle higher power and beam lead PIN diode has bad thermo diffuse properties,a power substitution method is proposed to verify PIN switch designs. Over hot is the main reason of PIN switches'failure, therefore thermo-resistance and device dissipation power measurement to estimate the inner temperature accurately is necessary dramatically. PIN diode used as thermo sensor and heating component in this method, low frequency pulse power amplifier is used to substitute RF power in thermo-resistance measurement, and pulse wide compensation is used in dissipation measurement, then equipment require reduced and flexible of equipment rising.The importance of reliability for PIN switch speaks for itself. Stable assembling techniques are vital to ensure reliability; therefore key assembling techniques are studied in the article.