Stepped‐impedance slotted microstrip‐fed patch antenna for on‐metal radio frequency identification applications

The paper reports the bandwidth enhancement of a microstrip slot antenna for on‐metal RFID applications. Microstrip patch with a single conductive layer as wideband and conformal antenna is investigated. The proposed bandwidth enhancement is based on stepped‐impedance slot resonator integrated with an inset‐fed microstrip patch. Slots of different electrical lengths and impedances are configured to generate their respective and distinct resonances, and are subsequently overlapped to create wideband. Equivalent circuit modeling to characterize the antenna in terms of electrical lengths and impedances with respect to their resonances are investigated and reported. These resonances are optimized to overlap using certain numerical equations and the commercially available 2D/3D EM solvers. The resulting antenna is thereafter stamped on the external coating of the pipeline of an RFID specific application for signal monitoring and pipeline integrity.