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.