Title :
An impedance modulated class-E polar amplifier in 90 nm CMOS
Author :
Ingels, M. ; Chironi, V. ; Debaillie, B. ; Baschirotto, A. ; Craninckx, J.
Author_Institution :
imec, Leuven, Belgium
Abstract :
This paper presents a digital amplitude modulator for a polar transmitter. The instantaneous output power is modulated by adjusting the amplifier´s load through a digitally controlled impedance transformation network. The modulator is suited for modulation schemes with moderate peak-to-average power ratio (PAPR), such as π/4 DQPSK. The modulator may also be used for fine gain control in constant envelope modulation schemes. A class E amplifier with digital impedance amplitude modulation is integrated in 90nm CMOS. It achieves a peak output power of 9dBm with a PAE of 30% when powered from a 1.2V supply. The measured EVM is 2.6% for a 6dBm π/4 DQPSK modulated signal with 2Mb/s signal rate at 2.4GHz RF frequency.
Keywords :
CMOS digital integrated circuits; amplifiers; modulators; CMOS; DQPSK-modulated signal; EVM; PAE; PAPR; constant envelope modulation schemes; digital amplitude modulator; digital impedance amplitude modulation; digitally-controlled impedance transformation network; fine gain control; frequency 2.4 GHz; impedance modulated class-E polar amplifier; peak-to-average power ratio; polar transmitter; size 90 nm; voltage 1.2 V; CMOS integrated circuits; Capacitors; Impedance; Modulation; Power amplifiers; Power generation; Switches;
Conference_Titel :
Solid State Circuits Conference (A-SSCC), 2011 IEEE Asian
Conference_Location :
Jeju
Print_ISBN :
978-1-4577-1784-0
DOI :
10.1109/ASSCC.2011.6123567
