Apparatus, and corresponding method, relates generally to a microelectronic device. In such an apparatus, a first conductive layer is for providing a lower interior surface of a circuit structure. A plurality of wire bond wires are interconnected to the lower interior surface and spaced apart from one another for providing at least one side of the circuit structure. A second conductive layer is for providing an upper interior surface of the circuit structure spaced apart from the lower interior surface by and interconnected to the plurality of wire bond wires. The plurality of wire bond wires, the first conductive layer and the second conductive layer in combination define at least one opening in the at least one side for a signal port of the circuit structure. Such circuit structure may be a signal guide circuit structure, such as for a signal waveguide or signal cavity for example.