Computer aided equivalent circuit model of SIW cavity backed triple band slot antenna

摘要

In this article, a study of planar triple band unidirectional Substrate Integrated Waveguidern(SIW) cavity backed slot antenna using equivalent circuit model is presented.rnThe proposed antenna uses a modified dumbbell shaped slot of much larger lengthrnplaced in a planar SIW cavity to excite three closely spaced SIW cavity hybrid modesrnwhich help the slot to radiate into free space. The design is analyzed with the help ofrnequivalent circuit model to predict the resonant frequencies of the design and also tornexplain the excitation mechanism of the proposed slot antenna. The proposed circuitrnmodel is validated by comparing its performance with the simulation model for arnwide range of parametric variation. The relationship between modification in designrndimension with the variation of coupling between feed line and cavity modes is studiedrnwhich gives a design guideline for the proposed antenna. The fabricatedrnprototype of the antenna resonates at 7.39, 9.43, and 14.79 GHz with a gain of 3.2,rn4.9, 4.7 dBi and front-to-back ratio (FTBR) of 10 dB, respectively, at three resonantrnfrequencies which makes it suitable for C (4–8 GHz), X (8–12 GHz), and Ku (12–rn18 GHz) band applications.