Title
Beamformer with constant-Gm vector modulators and its spatial intermodulation distortion
Author
Soer, M.C.M.
Klumperink, E.A.M.
van den Broek, D.J.
Nauta, B.
van Vliet, F.E.
Publication year
2017
Abstract
Spatial interference rejection in analog adaptive beamforming receivers can improve the distortion performance of the circuits following the beamforming network, but is susceptible to the nonlinearity of the beamforming network itself. This paper presents an analysis of intermodulation product cancellation in analog active phased array receivers and verifies the distortion improvement in a four-element adaptive beamforming receiver for low-power applications in the 1.0-2.5-GHz frequency band. In this architecture, a constant-Gm vector modulator is proposed that produces an accurate equidistance square constellation, leading to a sliced frontend design that is duplicated for each antenna element. By moving the transconductances to RF, a fourfold reduction in power is achieved, while simultaneously providing input impedance matching. The 65-nm implementation consumes between 6.5 and 9 mW per antenna element and shows a +1 to +20 dBm in-band and out-of-beam third-order intercept point due to intermodulation distortion reduction. © 2017 IEEE.
Subject
Analog beamforming
compression point (CP)
intercept point
interference nulling
mixer
phase shifter
phased array
receiver
spatial filtering
switched capacitor
vector modulator
Antenna phased arrays
Antennas
Beamforming
Frequency bands
Intermodulation distortion
Modulators
Interference suppression
Intermodulation
Mixers (machinery)
Receivers (containers)
Active phased array
Adaptive Beamforming
Distortion performance
Input impedance matching
Inter-modulation products
Low power application
Spatial interference
Third order intercept points
Compression points
Intercept points
Switched capacitor
Beam forming networks
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http://resolver.tudelft.nl/uuid:a69d396c-ef5e-4296-b410-26adc7d29378
TNO identifier
954877
Publisher
Institute of Electrical and Electronics Engineers Inc.
ISSN
0018-9200
Source
IEEE Journal of Solid-State Circuits, 52 (52), 735-746
Document type
article