In this paper, a 24-30GHz wideband power amplifier for millimeter-wave 5G communication is presented. Wideband small-signal matching is achieved with a staggered tuning technique. The input of the driver stage is matched at 30 GHz and the input of the power stage is matched at 24 GHz. A high-coupling-coefficient transmission line transformer (TLT) matching network is used for wideband output impedance matching. It compensates the large-signal device output capacitance for the operating frequency. To improve linearity, active feedback linearizer (AFL) and 2nd harmonic termination techniques are used. At the operating frequency, it achieves 19.8-21.7 dB peak gain, 15.6-17.7 dBm OP1dB 17.4-19.3 dBm Psat, and 20.4-31.4% PAEpeak. The 3-dB bandwidth is 23.2-31.0 GHz, and the core size is 0.134 mm2.