Compact printed double-folded inverted-L antenna for long-range RFID handheld reader

A novel compact printed double-folded inverted-L antenna is presented. The radiator is modified from a printed inverted-L antenna by extending and folding its radiated arm. A unidirectional radiation pattern is obtained as the radiator is mounted on a vertical printed rectangular ground. A slit etched on the ground of proper length and position is used to improve antenna directivity and suppress backward radiation. Measured results indicate that the proposed antenna has a good impedance characteristic (9% for return loss less than 10%dB), excellent front-to-back ratio and forward gain of 5.09%dBi. The antenna is applicable for long-range RFID handheld reader application.