I am designing DC block capacitor in LTCC that can able to surpass till 50 GHz. But the problem is strong return loss at the frequencies greater than 10 GHz. I am trying to accomplish this with Interdigital capacitor technique. Does anybody have idea regarding to eliminate this problem?
Interdigital capacitor uses the same strategy of having Metal-LTCC Tape(Dupont 943)-Metal but it is in Multilayer(benefits of LTCC) to reduce the total covered area of metallic plate on a single tape.
Reducing the dimesion of metallic strip improves S21 but at the cost of S11 i.e. great return loss (not a perfect DC blocking element).