Substrate-integrated waveguide (SIW) technology has recently drawn attention to its benefits in the microwave field, such as integration in planar microwave circuits, low manufacturing cost, and high-quality factor compared to other technologies. In this paper, a broadband and high gain SIW cavity-backed L-shaped slot antenna structure has been designed and made for X-band applications. Three pairs of L-shaped half-wave resonators are placed on the lower wall of the cavity (backed-slots) to further expand bandwidth and improve gain. The final antenna designed operates on a band ranging from 9.4 to 10.5 GHz with a bandwidth of 11%. Moreover, the gain reaches a value of 9.5 dBi. The final antenna is realized on a Rogers RT/Duroid 5870 substrate. The gain, the reflection coefficient, and the radiation patterns are measured and compared to the EM simulation results and a very good agreement is obtained. The proposed cavity-backed L-shaped slot antenna gives a good compromise between a high gain and a large bandwidth.
