I was doing a literature research on microwave filters and to me it looks like passive SAW filters/resonators have the highest quality factor below 1.5 GHz, but with a high power loss. Coupled planar coils/stripline (U-shaped) do not really reduce the phase noise in principle, but would be easier to fabricate. Active LC-circuits are probably better.

What about magnetic materials based filter/resonators based on ferrites/YIG/Permalloy and ferromagnetic resonance? Downsides seems to me that ferromagnetic resonance is not present in the MHz regime, rather GHz.

What I need:

  • between 100-500 MHz phase noise filtering at a distinct frequency, doesn't have to be tunable, as its purpose is to reduce phase noise of natural nano-oscillators with high phase noise
  • passive and possibly lower loss than SAW
  • input signal around 0 to -10 dBm and should stay above -20 dBm
  • below mm² size on-chip
  • fabricable with laserlithography, dry/wet etching, sputtering techniques

Is the SAW-resonator the best option I have?

  • \$\begingroup\$ suppose you have 499MHz natural oscillator; use mixer to down-convert to 1MHz, run thru moderate-Q 1MHz LC, then up-convert to 499MHz. \$\endgroup\$ Jul 29 '19 at 3:24
  • \$\begingroup\$ @analogsystemsrf Thank you for the suggestion, so I don't quite get it and I'm no electrical engineer. Couldl you provide a reference/IEEE paper so I get an idea what the system would like be to fabricate myself on-chip? I saw you can wound up some coils yourself to reach good filter, but has to be on-chip planar and passive in best case. Why you think down/up-conversion through Filter is best to reach for instance a 250 MHz oscillator signal with little phase noise or better than SAW. We really have to fabricate this and will be part of a PhD work. Thanks \$\endgroup\$ Jul 29 '19 at 10:01

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