Two balance amplifiers operating at 2.5∼12-GHz with 1dB gain flatness and under 10 dB return loss are presented. Low loss broadband quadrature power splitters for BAs are realized on glass integrated passive device (GIPD) and low temperature cofired ceramic (LTCC). For 0.18-µm CMOS unit amplifier in BA, output matching network based on 3rd order band pass filter is used for optimum output power and good return loss. These BAs demonstrate widest bandwidth with smallest gain variation among power amplifiers under 15 GHz, and highest ratio of OP1dB to power stage transistor size is achieved on CMOS process.