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. 2023 Jul 7;23(13):6236. doi: 10.3390/s23136236
Algorithm 1: Designing a Regenerative Amplifier-Based Active Microwave Resonator.
  • 1:

    Set desired operating central frequency ((f1+f2)/2)

  • 2:

    Design a passive CCSRR to obtain desired operating frequencies (f1,f2)

  • 3:

    Select a suitable BJT considering frequency response and noise characteristics ≈f1,f2

  • 4:

    Design the common emitter amplifier circuit with collector-feedback biasing components to ensure BJT operates in its active region

  • 5:
    Design TLs to feed the CSRR in a two-port configuration:
    1. Calculate the required length and width of the TLs to act as phase shifters
    2. Connect the transmission lines to the CCSRR input and output
  • 6:

    Design a positive feedback network, considering Barkhausen  [3], and connect it from the BJT collector to the resonator input through the phase-shifting TL and close the loop with another phase-shifter TL from CSRR output to the BJT base.

  • 7:

    Optimize feedback network for sufficient loss compensation without self-oscillation

  • 8:

    Verify stability and Q-factor enhancement through simulations on f1