Hexagonal SIW Cavity-Backed Self-Quadruplexing Slot Antenna

In this paper, based on the hexagonal SIW cavity a new type of self-quadruplexing slot antenna is proposed. Four rectangular slots are etched on the top metal plate. This antenna is designed for quad-band frequency operation (9. 4GHz, 7.1 GHz, 8.2 GHz, 6. 3GHz). The complete antenna and feeding structure are designed on a single substrate. This is making antenna small in size, low profile and cost effective. The proposed antenna prototype is backed by quarter-mode SIW cavity (QSIW) which is excited by 50 Ω microstrip line. SIW cavity show resonance at four different frequency in X-band on excitation of higher order mode. This Higher order Cavity mode (TM
₃₁₀
) excitation is mainly responsible for achieving high gain. The design principle and simulated results for this slot antenna is presented in the form of reflection coefficient, isolation among the ports, gain of the antenna at the corresponding resonant frequency and radiation pattern. The isolation among all four ports is found to be good greater than 30 dB. From radiation pattern cross-polarization level is found to be around -20dB, the front-to-back ratio in all the frequency band is found to be about 15 dB.