STUDY AND MODELING OF DYNAMIC PROPERTIES OF UHF POWER MOS-TRANSISTORS

Recent progress in the field of power MOSFET's aimed al fabricating de vices whose performances in the power and frequency domains offer the opportunity of working in VHF and UHF bands. In telecommunications, th e main application is the output stage (emission) in repeaters of mobi le radiotelephony in the narrow bands of 890-915 MHz and 935-960 MHz. designed for the European system GSM (Global System for Mobile communi cations). In this paper. the main properties of the power MOSFET are a nalysed using an original physical model. This model is further simpli fied and embedded in the softwares SPICE and ELDO. Comparing the simul ated and experimental static and small signal characteristics as well as the behaviour of resistive switching allows validation of our appro ach. Then, an UHF power MOSFET amplifier stage is analysed by consider ing a time domain methodology. Good agreement is found between experim ental and simulated results on power gain, power output. large signal impedances and intermodulation distortion products.