Reconfigurable broadband printed monopole antenna for portable smart IoT applications

The proposed work presents a design of a smart printed monopole antenna separated from a Hexagonal Matching Load (HML) with an air gap. The patch is fed by a coplanar waveguide, while the HML is connected to the ground plane through two pin diodes to realize antenna reconfiguration through controlling the surface current motion. The antenna structure is mounted on FR-4 epoxy substrate with size of 23 mm x 30 mm to fit the portable devices. After running four different switching scenarios, an observable change in the antenna performance is demonstrated. The proposed antenna provides a gain of 3.1 dBi at 2.45 GHz when the two diodes are switched ON. However, the antenna gain is changed to 1.6 dBi when the two diodes are set OFF. It is demonstrated that the proposed technique shows an effective approach to control the antenna performance without the need for DC blocking capacitor for RF choke. Nevertheless, the Specific Absorption Rate (SAR) effects are evaluated with respect to the human head tissues for all considered scenarios. Finally, the antenna radiation leakages to the human body are also tested numerically and experimentally for validation.