What is RLC equivalent circuit of cavity resonator, Series or parallel RLC?
I think you need to specify the coupling method (e.g. capacitive, inductive) before discussing equivalent circuits.
Parallel RLC and series RLC circuits are always convertible.It depends on authors preference.
I have another related question. At resonance parallel RLC circuit acts as an open-circuit with some R resistance to ground. And in several sources I read than active device sees such resonator as an open-circuited line. Length of this open-circuited line is measured from active device to resonator coupling point. But when I look at S11 of line coupled to DR it looks more like S11 of band-pass filter or any other similar element which is matched to nearly 50 Ohm at some frequency. At least in simulation. If open-circuited equivalent is correct, then I would expect to see huge reflections or at least mismatch between 50 Ohm and RLC's remaining R value at resonance frequency.
I really don't understand what "open-circuited line" means in this context. Any transmission line has a characteristic impedance. If it has sufficient length and isn't terminated with it's characteristic impedance, it will show resonances.
Sketch an equivalent circuit with all elements for a detail discussion.
I will post images as soon as possible. Now some question, writing from phone. Assume I use transformer (pins 1,2 on one side and 3,4 on isolated side) and parallel RLC to create equivalent schematic of resonator. My current problem is that resonator is directly coupled to line (inset line in SIW cavity).
Transformer pin1 to gate line, pin3&4 to RLC.May I terminate transformer to ground on pin2 then? I am sorry no images yet. Here is good example of SIW cavity resonator used in series feedback:
https://www.researchgate.net/publica...ed_Oscillators
I want to know how to use transformer to represent coupling to such resonator, when line is directly connected to cavity.