chebychevfilterdesignmethod.pptVIP

Chebychev Filter Design 7-Pole Coaxial Filter Filter response depends on antenna distance, resonator spacings, and resonator lengths. Note that the bottom of each resonator and its bucket form an open circuit. Study a few variables in isolation: frequency Study a few variables in isolation: spacing Coupling expressed by K: K = 2(f2-f1) / (f2+f1) Study a few variables in isolation: antenna distance QL is the loaded Q of this resonator – antenna – transmission line combination Low-pass prototype method: basic structure Low-pass prototype method: g-values Low-pass prototype method: impedance inverters N=7 Low-pass prototype method: lowpass – bandpass transform Low-pass prototype method: denormalization, resonant frequency Low-pass prototype method: denormalization, bandwidth Low-pass prototype method: introduction of unloaded Q Low-pass prototype method: final model, N=6 Low-pass prototype method: final model, N=7 How to generate an initial design using this information Wanted: a 7-pole filter Example Curve-Fitting in Serenade What Serenade tells us We thought we were creating a filter with Q = 31.5and resonant frequency of outer resonators 400 MHz.. Serenade tells us we obtained a filter with Q=32.93and resonant frequency of outer resonators 400.491 MHz. Serenade gives us similar information about coupling between resonators and resonant frequencies of inner resonators. The calibration projects, shown earlier, tell us what the adjustments need to be in the HFSS model to get closer to the desired result. Initial and Corrected Filter, S21 Initial and Corrected Filter, S11 Electric-Field Animation Close-up of electric field Sensitivity Analysis – Antenna Distance Sensitivity Analysis – Outer Resonator Length Sensitivity Analysis – Spacing One Resonator Pair S21-comparision lossless / silver Conclusion Design time from reduced weeks to days No more prototyping No need for a lengthy fine tuning process with a large number of tuning screws Straight from