Title :
Transmitter Linearization by Beamforming
Author :
Liang, ChuanKang ; Razavi, Behzad
Author_Institution :
Electr. Eng. Dept., Univ. of California at Los Angeles, Los Angeles, CA, USA
Abstract :
Millimeter-wave transmitters designed for dense signal constellations must deal with severe linearity-efficiency trade-offs. This paper proposes a method of blending beamforming and linearization that reduces the number of power amplifiers and avoids the loss of on-chip transformers. Two constant-envelope beams are combined in space to deliver a variable-envelope signal, relaxing the linearity of transmitters. A dual-transmitter prototype fabricated in 65-nm CMOS technology and designed for the 60-GHz band produces a 16QAM output of +9.7 dBm with 11% efficiency.
Keywords :
CMOS integrated circuits; array signal processing; linearisation techniques; millimetre wave power amplifiers; quadrature amplitude modulation; radio transmitters; CMOS technology; QAM; beamforming; constant-envelope beams; dense signal constellation; dual-transmitter prototype; efficiency 11 percent; frequency 60 GHz; linearity-efficiency trade-offs; millimeter-wave transmitter; on-chip transformer; power amplifier; size 65 nm; transmitter linearization; Array signal processing; Baseband; CMOS integrated circuits; Couplings; Receiving antennas; Transmitters; Beamforming; injection-locked power amplifier; millimeter-wave circuits; mm-wave phased-array transmitter; outphasing technique; phase shifter; transmitter linearization;
Journal_Title :
Solid-State Circuits, IEEE Journal of
DOI :
10.1109/JSSC.2011.2148530
