An argument for the geometry based frequency range extension of tunable MEMS capacitors is presented. It is shown that, besides reducing the length of the feed arms, the parasitic inductances in a parallel-plate MEMS capacitor can be reduced further by optimising the plate geometry. Extension of the self resonance frequency is demonstrated with reduced circumference of the plate, due to high-frequency currents travelling around the edge of the plate and acting as a major component affecting the self-resonance frequency (SRF) of the capacitor. Full-wave 2.5-D electromagnetic simulation results using Agilent EEsof's ADS Momentum are presented that demonstrate the improvement in self-resonance frequency of circular and symmetrically fed structures. It is shown that efforts in shortening current paths by means of slots did not yield significant further improvement.