A design methodology of CMOS cross-coupled oscillator operating close to the transistor's maximum oscillation frequency (fmax) is proposed by utilizing the loop impedance matching and phase shift control technique to maximize the oscillator's loop gain. A fundamental oscillator following the proposed design methodology has been implemented in 65-nm CMOS. The measured results show that the oscillator achieves 192.3-GHz oscillation frequency, which is 71.1% of the transistor's fmax. The spectrum output power is -10.4 dBm with the phase noise of -100 dBc/Hz at 10 MHz offset. The oscillator draws only 14-mA current from a 1.2-V power supply.