A method, system andor NFC enabled mobile device is provided for executing an electronic contract on NFC enabled mobile devices. In one embodiment, a switch system for a virtual power grid includes a first transistor for connecting a power supply to a node of a virtual power grid for an isolated region of circuitry via the first transistor upon a receipt of a first control signal to turn on the first transistor. The dual-mode resonator and the TEM single-mode resonator form a filter apparatus. The spatial coordinates of the medical finding identified by the encapsulated imaging unit are relayed to the extracorporeal image acquisition system to allow an extracorporeal image to be obtained based on those spatial coordinates. Operation of either one of the two flow control members actuates a membrane switch assembly. The method comprises: fitting into the recess a doping mask having selectively formed openings to selectively cover the second major surface with the doping mask; and selectively introducing dopant into the second major surface.