SIW-cavity based frequency reconfigurable antenna for IoT, WLAN, and 5G applications

Abstract In order to minimize antenna complexity and improve gain, a new compact size low profile SIW-cavity-based frequency reconfigurable antenna is presented for IoT, WLAN, and 5G applications. The proposed antenna miniaturization is achieved by incorporating SIW cavity using metallic vias. The reconfiguration mechanism is accomplished by etching a circular ring slot and a C-shaped slot at the top metallic layer of the substrate. The frequency switching mechanism from low to high state is provided by eight PIN diodes. The diodes are placed in a symmetrical order along circular ring slot. All the diodes are switched on simultaneously to achieve low-frequency state operation. However, the off state of the diodes shifts antenna operation from low to high-frequency state. The antenna is fabricated on a small size substrate with an overall electrical size of (0.4λ* 0.4λ).The proposed antenna resonates at frequencies 2.4, and 3.45 GHz with 220 MHz and 470 MHz bandwidth respectively in low-frequency state. In high-frequency state, the antenna resonates at 5.8 GHz with 200 MHz bandwidth. The proposed antenna achieves peak gain of 6.3, 6.7, and 5.9 dBi in the three bands, and stable radiation patterns are attained in the working frequency band of the antenna.