A wide half-power beamwidth antenna based on magnetic coupling in near-field (NF) regions and circular polarization (CP) in far-field (FF) is proposed for RFID multiservice applications in UHF band. The prototype consists of a cross-strip and an L-shaped strip on the top layer, fed by an F-shaped network on the bottom layer. CP electromagnetic wave is radiated by the cross-strip, and the antenna also simultaneously brings opposite directed currents (ODC) to generate strong magnetic field in near-field region. Half-power beamwidth is 100˚ in xoz-plane and 102˚ in yoz-plane, which can be used to scan for large regions. An 88 × 88 × 1.6 mm3 antenna has been fabricated on an FR-4 substrate to fit RFID applications. Measured tests on read range by observing feedback received signal strength indication (RSSI) values are carried out, exhibiting 100% read rate for near-field tags within 25 mm and exciting read distance for far field tags up to 1 m for large reading region of 170 × 170 mm2.
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