Design and Implementation of an X-Band Frequency Synthesizer for Radar Applications

This paper describes the design, development and testing of an X-band frequency synthesizer. The synthesizer consists of a voltage-controlled oscillator (VCO), a phase-locked loop (PLL) circuit and a reference oscillator. Commercially available components used in the design provide a low cost and short time to market solution. Typical output power of the synthesizer is +10 dBm. Loop filter is designed for a low phase margin of 48deg. Spur levels are below -9.6 dBc. The complete circuit is realized using an X-band VCO, a frequency divider (+8), a digital frequency synthesizer chip (DPLL), a loop filter and a microcontroller. The design is very immune to environmental changes especially temperature variations and is tested up to 100degC.