Design of a Broadband High Spurious Suppression Frequency Synthesizer

Frequency synthesizer plays an important part in RF systems, which generates different kinds of RF signals required by the system, including the transmit signal, the local oscillator signal and the reference signal. This paper presents a design of a broadband high spurious suppression frequency synthesizer. The design uses direct digital synthesis (DDS) baseband combined with phase-locked dielectric resonance oscillator (PDRO) and phase-locked loop (PLL) point frequency for frequency conversion, and realizes high spurious suppression by selecting suitable frequency combination. The testing results of the frequency synthesizer are as follows: Output frequency: 12-20GHz, output power ⩾10dBm, spurious suppression ⩾ 70dBc, phase noise ⩽-104dBc/Hz@1kHz. The synthesizer has the advantages of small size, wide operating band, high spurious suppression and low phase noise.