Frequency-Reconfigurable Hybrid SIW-Based Self-Diplexing Antenna Using Solid and Liquid Dielectric Loading

This paper presents a novel frequency-reconfigurable self-diplexing antenna (SDA) utilizing a hybrid substrate-integrated waveguide (SIW). The antenna comprises a radiating slot, a feeding network, and a hybrid SIW cavity featuring half-mode circular and half-mode rectangular SIW structures. The unique feature of this antenna lies in its fine-tuning capability of each resonant frequency by inserting or injecting solid and liquid dielectrics into designated etched pockets. Experimental results demonstrate that the proposed structure can be effectively tuned within the frequency range of 2.7 to 3.47 GHz for the lower band and 4.05 to 4.96 GHz for the upper band. The mutual coupling between the ports is better than 20.4 dB, and the antenna maintains consistent radiation patterns across the entire operating range. The proposed tunable antenna, featuring precise frequency tuning capability, compact size, and stable radiation patterns, is well suited for various applications, including wireless communication systems, biomedical telemetry, microwave imaging, WiMAX, and Wi-Fi.