Title :
High-efficiency linear amplification by dynamic load modulation
Author_Institution :
Green Mountain Radio Res. Co., Colchester, VT, USA
Abstract :
Load modulation is a new technique in which amplitude-modulated signals are produced with high efficiency by dynamic variation of the load impedance of the power amplifier. The prototype MOSFET PA operates in class E and produces a peak output of 19 W at 30 MHz with an efficiency of 66 percent. Load modulation is accomplished by a T network with a pair of high-voltage MOSFETs that act as a voltage-variable capacitor. The envelopes of a variety of different signals are successfully generated. For a Rayleigh (multi-carrier) envelope with a 10-dB peak-to-average ratio, the average efficiency is twice that achieved in linear operation of the same PA.
Keywords :
MOSFET circuits; VHF amplifiers; amplitude modulation; circuit tuning; power amplifiers; 19 W; 30 MHz; 66 percent; MOSFET power amplifier; Rayleigh multi-carrier envelope; T network; amplitude-modulated signals; class E power amplifier; dynamic load impedance variation; dynamic load modulation; electronically tunable network; high-efficiency linear amplification; high-voltage MOSFETs; peak output; peak-to-average ratio; voltage-variable capacitor; Amplitude modulation; Band pass filters; Dynamic range; Electric variables control; High power amplifiers; Impedance; Peak to average power ratio; Power generation; Radio frequency; Voltage;
Conference_Titel :
Microwave Symposium Digest, 2003 IEEE MTT-S International
Conference_Location :
Philadelphia, PA, USA
Print_ISBN :
0-7803-7695-1
DOI :
10.1109/MWSYM.2003.1210470
