A 40 GHz CMOS unit-cell power amplifier for radio-over-fiber

A 40 GHz 130nm CMOS power amplifier unit-cell is designed and simulated for use in a downlink transmitter of a millimeter-wave radio-over-fiber system. The system will be used as a complementary solution to Fiber-to-the-Home where geographical limitations and cost considerations are critical. The power amplifier unit-cell has a single-stage cascode structure for stability and input-output isolation. In addition, it utilizes slow-wave transmission lines for matching. The P1dB output power is 10 dBm, gain is 7.4 dB, and PAE is 10%. The PA unit-cell is to be used in a multi unit-cell power combining structure on silicon for larger output power at 40 GHz.