Wideband Substrate Integrated Waveguide Antenna for Full-Duplex Systems

In this letter, a low-profile and wideband substrate integrated waveguide (SIW) antenna is proposed and validated for full-duplex systems. The proposed antenna operates at 4.9 and 5.8 GHz wireless local area network bands. Each resonator of the antenna consists of a modified half-mode SIW(HMSIW) cavity, and excited by a 50 Omega coaxial probe. The wideband response is achieved by coupling the fundamental TE10 mode with the perturbed TE10 mode of the HMSIW cavity. The compactness of the proposed design is obtained using two rectangular slots near the closed-ends of the cavities. By properly optimizing the overall geometry, the proposed design exhibits a 10 dB fractional bandwidth of 8.2% (4.78-5.2 GHz) and 7.7% (5.70-6.16 GHz) in the lower (4.9 GHz) and upper (5.8 GHz) frequency bands, respectively. The bandwidths of both frequency bands can be controlled by adjusting the coupling between modes. A high isolation (>30 dB) between the two ports is observed due to series of metallic vias between them. This antenna has compact size (0.007 lambda(3)(g)) with high gains of 5.24 and 5.37 dBi at 4.9 and 5.8 GHz, respectively. The proposed design is suitable for emerging full-duplex systems, thanks to its small size, high isolation, wide bandwidth, and independent resonance and bandwidth control.