Design a stable 14-to-20-GHz source

Abstract: Careful selection of key components and the use of straightforward multiplication schemes can be applied to the design of a low-noise frequency synthesizer for Ku-band signals to 20 GHz. ___________________________________________________________________________ Frequency synthesizers provide the local oscillator (LO) signals as well as transmit signals in many communications networks. They must be stable, with low phase noise and good spectral purity, to support the complex modulation formats that are now common to many wired and wireless communications networks. To serve as a signal source in such networks, a low-noise frequency synthesizer capable of tuning from 14 to 20 GHz (Ku-band operation) was developed with step size of 500 kHz and phase noise of-81 dBc/Hz offset 10 kHz from the carrier. By doubling the output of this 20-GHz frequency synthesizer a total of three times, it can be extended in frequency for millimeter- wave radar systems and radio links operating at frequency bands of 57 to 64 GHz and 71 to 77 GHz. Improvements in silicon CMOS technology, notably its enhanced capabilities for RF, microwave, and even millimeter-wave circuits, have supported its expanding applications in wireless transmissio