a choke ring apparatus for attenuation of electromagnetic waves in a mobile platform fuselage includes a ground plane mounted on a surface of the fuselage . the choke ring has an axial circular window and a series of concentric circular ring segments on the ground plane arranged coaxially about the axis of the window . the circular ring segments extend from the ground plane . the ring segments defining at least one groove therebetween . the ring segments have a flat ridge at the edge , and each groove has a depth defined by a pair of adjacent ring segments . the width of the flat ridge surfaces and a width of the groove between adjacent ring segments are approximately equal . the depth of the groove is determined based on a predetermined resonant frequency , such that the choke ring apparatus selectively attenuates electromagnetic waves in a region of the resonant frequency when propagating through the window .