Cite some of those "various research papers" you have come across. Capacitive reactance varies with frequency, capacitance not so much. Tell us what you are trying to DO, please. No half-baked ideas of how to do it, nor off-the-wall statements about how capacitance varies as a function of frequency. If you have found a capacitor that behaves like that, please post a link to where we can buy it. Be sure to include voltage rating, capacitance range, and other "stuff" engineers use to specify capacitors for use in their circuits.