microstrip resonator simulation question

[yefj]

Hello, a resonator which is an open circuit stripline was built as shown bellow exactly as described in the example bellow.
Smith chart and S-params and E-field are as shown bellow.
I am used to think that at resonance our S-params is supposed to very low.
Where did i go wrong?
Maybe resonance and being impedance matched is no the same thing?
Thanks.

 

[D.A.(Tony)Stewart]

Your initial result is below showing resonance is just past 4.86 GHz or an error of -2.8%.

The conductor has air on one side so fill factor and width affect the effective Dk or Er

--- Updated Jun 7, 2023 ---

Here is a similar 5 GHz tank resonator with 40 dB gain with Rs = 0.5.

What is the impedance of the tank cct to yield this gain?
Why is there no gain with Rs=50 ? (0dB) same with half wave delay line.
. the aim here is to reinforce your understanding of impedance of a reactive delay line that has an equivalent lumped LC parameters for a 1st order approximation..

 

[biff44]

it is important to understand the BASICS before you go trying to design microwave circuits. Consider this resonant circuit:

Since you are talking resonators, R is the equivalent loss from the inductor and capacitor. say its 2 ohms.
thoroughly investigate its properties. Impedance, reflection coefficient vs frequency. Vary the reactance values, then increase the resistance and see how the response changes.

then do the same with this circuit:

it is also a resonator, and shares SOME of the characteristics of the series circuit. but in some respects it is different, especially at the exact resonant frequency.

When you understand this, then the microstrip resonator will start to make sense

 

[D.A.(Tony)Stewart]

The spectrum slider scale and 3 position switch are interactive in my previous example . All resonate near 5 GHz. Some are over-damped.

Series resonance is X(f) = 0 ohms, Parallel resonance has 1/X(f)=0 The linear Q
may be derirved from log gain, series Qs=X/R, Parallel Qp=R/X

This simulation link is http only but is safe.

 

[D.A.(Tony)Stewart]

any questions?
What did you learn?