Shielded HMSIW-based frequency-tunable self-quadruplexing antenna using different solid/liquid dielectrics

This article proposes a frequency-tunable self-quadruplexing antenna based on a shielded half-mode substrate integrated waveguide (S-HMSIW). In order to reduce the size of the HMSIW cavity resonator and to obtain quad-band characteristics, a modified E-shaped slot is engraved on the top of the metal. The experimental validation is carried out after analyzing the data using a circuit model. Flexibility of each resonant frequency is enabled by integrating solid and liquid dielectrics of different permittivities within the designated etched region of the proposed antenna. With a broad tuning range of 3-8.5 GHz, the operating frequencies can be tuned individually according to the application-driven demands. Furthermore, the port isolation is better than 23.5 dB in all four bands. The proposed antenna, with distilled water-filled pockets, exhibits realized gain of 3.82, 4.1, 4.3, and 5.6 dBi at 5.17, 5.76, 3.55, and 7.03 GHz, respectively. The antenna features stable radiation characteristics in all bands and throughout the entire tuning ranges. Owing to its compact size, broad tuning capability, consistent radiation patterns, and competitive isolation levels, the presented design can be considered a suitable solution for compact tunable devices required by the existing and emerging application areas, especially multi-standard wireless communications.