A new approach to design a frequency synthesizer using Direct Digital Synthesis technique

In this paper a new method to generate a high resolution Ka-band frequency synthesizer is presented. Using a DDS (direct digital synthesizer) as a central oscillator followed by a chain of precisely designed multipliers, a very high resolution and fast switching time Ka-band synthesizer with acceptable phase noise is achieved. The output power of Ka-band synthesizer is around -5 dBm all over 5 GHz bandwidth. To implement the design, a DDS having approximately 0.5 Hz resolution and proper phase noise around -145 dBc/Hz is used. The 330-400 MHz output frequency of the DDS is increased to the desired 24-29 GHz band.