In this article, efficient integration approach of building large‐scale active‐phased array antenna (A‐PAA) for millimeter‐wave (mm‐wave) is presented. In this approach, large‐scale A‐PAA is constructed from smaller size A‐PAAs (modules) with inter‐element spacing of half‐wave length and assembled into efficient planar waveguide feeding platform based on substrate integrated waveguide (SIW) technology. Simple low profile vertical RF‐connection between the SIW splitter/combiner outputs and the modules using surface mount super‐mini board‐to‐board (SM‐SMC) is presented. Embedded metallic via‐pad transition integrated into the SIW board is employed to match the SM‐SMC to the SIW mode at Ka band. Sixteen‐way power splitter with transitions to SM‐SMCs is designed at 30 GHz. The measured results of S‐parameters show insertion loss of <0.70 dB over the operating frequencies 28.50‐30.50 GHz.