A miniaturized Marchand balun combiner is proposed for a W-band power amplifier (PA). The proposed combiner reduces the electrical length of the transmission lines (transmission line) from about 80 to 30 degrees, when compared with a conventional Marchand balun combiner. Implemented in a 1 V, 65 nm CMOS process, the presented PA achieves a measured saturated output power of 11.9 dBm and a peak power added efficiency (PAE) of 9.0% at 87 GHz. The total chip area (with pads) is 0.77x0.48 mm2, where the size of the balun combiner is only 0.36x0.13 mm2.