A multi-mode mobile communication device includes a processing device, a memory sub-system, a communication sub-system operable to communicate with wireless access networks, and a protocol stack stored in the memory sub-system and executed by the processing device. An insulating material for use in high-frequency electronic parts comprising: a matrix component composed at polyimide, and fluorocarbon resin particles uniformly dispersed therein. The reflectors comprise a closed optical path and are configured to direct each of first and second light beams in a different counter-propagating direction in the closed optical path. Light traveling within the waveguide is reflected from the reflective surface along the elongated rearward side towards the forward side for viewing.