A Matching Technique for RF LDMOS Power Amplifiers

This paper presents the pre-matching and matching approach for RF LDMOS device in designing of high-power RF amplifier. A pre-matching circuit in flange and an input/output matching circuit on PCB have been developed for one RF LDMOSFET, so that it can be matched to the system characteristic impedance of 50Ω within a given frequency range of 869~960MHz. The measured results show that this RF LDMOS amplifier provides a 1dB gain compression point output power (P1dB) higher than 48.8dBm, a corresponding DC to RF conversion efficiency better than 66.4% and the third-order intermodulation (IM3) less than -30dBc.