ABSTRACT
Recently, complementary metal-oxide-semiconductor (CMOS) technology has been successfully extended to wireless transceiver circuits in the regime at millimeterwave (mmWave) frequencies. CMOS circuits are feasible for various applications, such as high-speed wireless data transmission in the 60 GHz band and automotive radar detection at 77 GHz. No matter what kind of applications, a signal source is a must in a mmWave system. In typical cases, a local oscillator (LO) signal is required for frequency conversion. In some cases, data can be directly modulated on a source to obtain amplitude, phase, and frequency modulating signals. Signal generation is a process that converts dc energy to radiofrequency (RF) power using the circuit block of an oscillator. Oscillator design faces performance challenge with the fundamental frequency directly at the mmWave frequency and beyond. It is difficult to obtain stable oscillation, and the phase noise is not so good. Besides, the energy conversion process is typically of low efficiency at high frequencies. A circuit normally consumes large dc power.
