Novel UHF near-field RFID reader antenna for handheld devices

A novel ultra-high frequency (UHF) near-field radio frequency identification (RFID) reader antenna is proposed for handheld devices. The antenna is composed of a circular loop, a parasitical split ring and a resistor. The parasitical split ring is used to miniaturize the antenna. The measured bandwidth is 140 MHz (826-966 MHz) for the reflection coefficient less than -10 dB, which covers the entire UHF RFID frequency band. The measured maximum reading rang of the antenna is 60 mm at the input power of 30 dBm. Measurement results show that the proposed antenna can greatly reduce power consumption for near-field UHF RFID handheld devices because the minimum input power for successful detection of tag is -12 dBm. The measured results agree well with the simulated ones.