SOI CMOS technologies feature high cut-off frequencies and superior temperature stability, which can meet different kinds of application requirements of microwave and millimeter wave radar transceivers. A class-A Stacked-FET power amplifier in 90 nm SOI CMOS technology was designed with output matching network omitted. The saturated output power and reliability of power amplifier were improved. A 24 GHz signal generator was designed based on this power amplifier. Influences of Dummy filled in semiconductor process to the performance of spiral inductor were studied and analyzed using electromagnetic simulations. The circuit was fabricated and tested. Measured results indicated that this chip can transmit a signal operating at 22.2-24.7 GHz with an average output power of 8.83 dBm and a peak output power of 10.5 dBm. The phase noise of the VCO at 1 MHz offset and 10 MHz offset are -91 dBc/Hz and -123 dBc/Hz. The area of the entire chip is 1.4×1.4 mm2.