A wireless electronic device includes a Substrate Integrated Waveguide (SIW), a first metal layer including one or more top wave traps, a second metal layer, a feeding structure extending through the first metal layer and into the SIW, and a reflector on the first side of the SIW. The reflector directly connects to the first metal layer and extends outward along a major plane of the first side of the first metal layer. The wireless electronic device is configured to resonate at a resonant frequency when excited by a signal transmitted or received though the feeding structure. The one or more top wave traps are configured to trap a signal radiated by the reflector based on the signal transmitted or received though the feeding structure.