Beamformer with constant-Gm vector modulators and its spatial intermodulation distortion
van den Broek, D.J.
van Vliet, F.E.
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.
To reference this document use:
compression point (CP)
Antenna phased arrays
Active phased array
Input impedance matching
Low power application
Third order intercept points
Beam forming networks
Institute of Electrical and Electronics Engineers Inc.
IEEE Journal of Solid-State Circuits, 52 (52), 735-746