Simulation, Modeling and Implementation of an Ultra-Low Phase Noise X-band Frequency Synthesizer

One of the most important components in telecommunication systems and radar activities are frequency synthesizers. Among the important parameters of a frequency synthesizer are phase noise, frequency resolution, programming speed, scanning rate and spur level in the output spectrum of the system. Typically, it is not possible for a frequency synthesizer to reach all of these parameters simultaneously. In other words, there are trade-offs between desired parameters. Among the structures of frequency synthesizers that can be used to achieve the optimal point for these parameters are multi-loop phase lock loop. In this paper, by presenting the noise model of different elements of a frequency synthesizer, simulations related to the achievable phase noise for a sample synthesizer in the X band are presented and finally the results of implementation of a sample synthesizer are presented.