hi frnds iam supposed to fabricate a combline bpf having 1.1% (FBW) and in the low pass prototype iam getting external quality factor around 190 and coupling coefficients very low(i want to design using transformer coupling) the problem is when i want to know the spacing b/w resonators whether i have to take resonators having via hole grounding or open circuit resonators to find the required external quality factor and coupling coefficients and give me a detailed explanation to get the desired coupling coefficients and external quality factor ..iam using ADS . and tell me whether i can to substrate of 3.38 or 10.2 which is best?
plzzzzzzz help