UWB InterDigital Capacitor

Hi every body, I need to design a UWB interdigital capacitor, my BW is 3 Ghz to 10 Ghz. I make some design and only work like a capacitor under 3 Ghz. The value of my capacitor is 2pf I thing is a high value for interdigital capacitor.
I need some help

Hi rtorreal,
It seems that your self resonance frequency is low. In order to make your structure work as a capacitor upto 10 GHz, u need to have self resonance frequency (where Q factor = 0) of at least 15 GHz. So, try changing ur geometry and investigate which portions are contributing the inductive effect.....try to change those structural shapes....