This paper proposes a novel corner-fed Circular Polarization (CP) reader antenna for handheld Ultra-High Frequency (UHF) Radio Frequency Identification (RFID) application. The CP mechanism is accomplished by a multi-bending feeding strip located at corner of a high dielectric constant (K = 60) ceramic substrate. By using the high dielectric substrate, the dimension of the proposed antenna can be effectively reduced to 27 × 27 × 4 mm3, which consists of a top radiating patch, an antenna ground plane, a coupling multi-bending feeding strip, and a SMA connector for RF input. The top radiating patch is printed on the top surface of the ceramic substrate and the antenna ground plane is formed on the opposite side. The central frequency of resonant band can be easily controlled by adjusting the size of the top radiating patch. By optimizing the coupling feeding mechanism, not only impedance matching can be achieved for bandwidth operation in Taiwan's UHF RFID band, but also two orthogonal field components with 90° phase difference for circular polarization are obtained. In addition, the proposed antenna is placed on an 80 × 80 × 0.8 mm3 FR4 system ground plane for reducing hand holding effect.
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