Low Phase Noise Concurrent Dual-Band Oscillator Using Compact Diplexer

Abstract

A novel C-band concurrent dual-band oscillator is presented in this paper. Two diplexers are cascaded back-to-back to realize two loop sub-oscillators. The phase noise of the oscillator is reduced significantly by using the cascaded high-Q diplexers as the frequency stabilization elements. Meanwhile, a highly pure dual-band signal was observed at the output port, which is contributed to the isolation characteristic of the diplexers. The diplexers can suppress the interaction between the two sub-oscillators. To obtain the property of compact size and high-Q factor, the SIW-CSRR structure is introduced into the design of diplexers. A C-band prototype has been designed and fabricated. The measured phase noise of the dual-band oscillator is dBc/Hz and dBc/Hz at 100 kHz offset from 4.18 and 5.49 GHz oscillation frequencies, which correspond to the figure-of-merit (FOM) of 188.7 and 189.1 dBc/Hz, respectively. The second-order and third-order intermodulation products of the two oscillation signals are suppressed to below dBc, as compared to the 4.18 GHz signal.Index Terms-Complementary split-ring resonator (CSRR), diplexer, dual-band, oscillator, SIW.

A novel equivalent circuit model for split ring resonator with an application of low phase noise reference oscillator

“…Oscillators with an oscillation frequency around 1 − 4 GHz band were listed. [18] outperforms since its oscillation frequency is higher and has better phase noise yet oscillation frequency of reported oscillator in this work can be scaled up via scaling resonant frequency of the SRR with almost no drawback in Q-factor and performance can be improved much further.…”

“…Variation of the phase noise with respect to offset bandwidth is given Fig.9. The figure of merit (FOM) is calculated as [18]:…”

Dual-Band Complementary Split-Ring Resonator (Csrr) With High-Quality Factor and Its Applications in Low Phase Noise Oscillators and Small Multi-Band Diplexers and Filters

“…Less power consumption can be obtained by choosing a better low noise transistor. One merit of the proposed oscillator, compared to the oscillators reported in the scientific literature [10][11][12][13][14][15][16][17][18][19][22][23][24][25][26][27][28][29][30][31][32][33][34], Figure 13. Circuit schematic of the low phase noise oscillator employing the SIW cavity CSRR resonator.…”

Low phase noise microwave oscillator with greater than 60 dB second‐harmonic suppression

“…At an oscillation frequency of 9.04 GHz, the measured phase noise is −111.9 dBc/Hz at 100 kHz offset. More examples can be found out in [16][17][18][19][20][21]. Unfortunately, there is no theoretical prediction on the lowest limit for phase noise.…”