Compact circularly polarized microstrip antenna for RFID handheld reader applications

A compact circularly polarized microstrip antenna (CPMA) with slits is proposed for radio frequency identification (RFID) handheld reader applications. The slits are cut onto the square patch radiator diagonally to reduce antenna size with circular polarization (CP) operation. A measured 3-dB axial-ratio (AR) bandwidth of around 4.0 MHz with 19.0 MHz impedance bandwidth at centre frequency of 920 MHz is achieved. The overall antenna size is 0.276¿
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× 0.276¿
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× 0.014¿
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. The proposed antenna can be a good candidate for RFID portable or handheld reader applications.