Adjusting of coupled filters with a VNA

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Hi

Need to adjust some coupled filters, (3 to 5  poles - below 500MHz)

Having read the app note 1287-8 from HP, it seems that "Time Domain Analysis" is the way to go

I do have
HP 8714ES w. opt. 100
Siglent SVA1032X w. DTF

None of these VNA's offer real Time Domain Analysis, but are the DTF options any good for adjusting filters?

I can't afford a E5071 or other fancy equipment, so I'm looking for a way to do it with what I have now, or the next step up
Maybe a HP 8753* with opt. 010?

How are you adjusting coupled filters?

[S57UUU]

I guess these are bandpasses?
You can tune them in frequency domain, with a normal network analyzer (even a scalar one).

Measure S11 (do not forget a load at port 2).

Tune all of the resonators way off (or short them). Do a response calibration (normalization).
Tune the first resonator, to get a minimum in S11 at center frequency. At this stage set the scale to 1dB/div or less, since the minimum will be very shallow. You can deepen it by introducing some loss (finger...) into resonator #2.

Next, tune resonator #2. Depending on your coupling between the resonators (filter width), the minimum will split into two, or just become deeper. If split, tune #2 so, that the two dips are symmetrical around center frequency.

Tune #3 to get three symmetrical dips, etc.

Marko Cebokli