A Beamformer with constant-gm vector modulators and its spatial intermodulation distortion

M.C.M. Soer, Eric A.M. Klumperink, Dirk-Jan van den Broek, Bram Nauta, Frank E. van Vliet

    Research output: Contribution to journalArticleAcademicpeer-review

    21 Citations (Scopus)
    461 Downloads (Pure)


    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 non-linearity 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 4-element adaptive beamforming receiver for low power applications in the 1.0 to 2.5 GHz frequency band. In this architecture, a constant-Gm vector modulator is proposed which 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 four-fold 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, out-of-beam IIP3 due to intermodulation distortion reduction.
    Original languageEnglish
    Pages (from-to)735-746
    Number of pages12
    JournalIEEE journal of solid-state circuits
    Issue number3
    Publication statusPublished - 1 Mar 2017


    • EWI-26902


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