A Highly Isolated M-Shaped SIW Backed Antenna for Quad-band Communications

In this work, a novel planar quadruple fed self-quadruplexing antenna for quad band operations employing substrate integrated waveguide (SIW) technology is presented. The proposed antenna is made on a single layer of RT/Duroid substrate. The topside of the cavity structure is converted to M-shaped slot, which forms four distinct patches and are energized by four independent 50-Ω feedlines. This alignment enables the antenna to function at four discrete frequencies 4.02 GHz, 7.34 GHz, 7.78 GHz, and 10.34 GHz with peak gain 3.1 dBi, 3.8 dBi, 4 dBi, and 4.2 dBi respectively. The proposed antenna achieves 29 dB as minimum isolation. It also provides flexibility for independent frequency redesign with a single variable. By combining advanced SIW techniques with a compact and versatile architecture, this proposed design is well-suited for the C-band and X-band communication. It will be more efficient and suitable for integrated handheld communication devices in the future that demands efficient multiband functionality and miniaturized designs.