An S-Band PLL Frequency Synthesizer for Agile Radar

This paper discusses the design of microwave frequency synthesizers, using PLL with fast switching and low phase noise, which can be used for radars and other microwave systems. The method of design, which considers compatibly the switching time and phase noise, is straightforward. A formula for evaluating frequency switching time is derived. It guides the designer to select directly the natural frequency Wn of PLL. A 2GHz synthesizer is introduced, which has 50¿s switching time and ¿110dBc/Hz SSB phase noise floor. The evaluations of switching time and phase noise using the method is listed. Scheme of measuring system and photographs of switching on oscilloscope and phase noise density characteristic on spectrum analyzer are given.