Low phase-noise oscillator based on SIW bandpass filter implementing at the Qsc-peak frequency

Abstract

ABSTRACTIn this paper, a novel low phase-noise oscillator employing an substrate integrated waveguide (SIW) bandpass filter (BPF) embedded with a complementary spiral resonator (CSR) is proposed. The Qsc-peak frequency is chosen for the design of the oscillator to achieve optimal phase noise performance. The CSR exited by TM01 mode has been etched on the top metal of the circular cavity. Three transmission poles and three transmission zeros can be obtained by the proposed SIW BPF which is regarded as the frequency stabilization element. Meanwhile, a short summary about how to obtain a high Qsc-factor to achieve low phase noise performance has been illustrated. A C-band oscillator using a field effect transistor has been designed and experimentally demonstrated at 5.71 GHz with a 147.6 dBc/Hz phase noise at 1 MHz offset frequency. Moreover, the output power is −1.49 dBm with a figure of merit of −209.2 dBc/Hz and less than −32.8 dBm spurious harmonics is obtained.