The present disclosure provides an electrode and an feedthrough for an implantable medical device. The user of the comparator stores his evaluation of the properties included in the targets to be evaluated in a database in the server in the data network using a graphic one- or two-dimensional evaluation frame. RF power coupled from a main antenna into the additional antenna is absorbed instead of being re-emitted into the main antenna and disturbing measurement of the reflected power level. Light of a desired wavelength is thus output from photonic crystal 2.