Design of UHF RFID Reader Antennas Using Coupled Line Power Divider and Narrow Bandpass Filter

作者：Liu, Qiang^*; Liu, Yuanan

来源：Applied Computational Electromagnetics Society Journal, 2014, 29(8): 647-654.

• Circularly Polarised (CP)
• coupled line
• filter antenna
• RF Identification (RFID) and Ultra-High-Frequency (UHF)

In this paper, a Circularly Polarised (CP) universal Ultra-High-Frequency (UHF) RFID reader antenna based on coupled line power divider is firstly proposed. The antenna features compact size, simple structure and low-cost and achieves Return Loss (RL)>= 25.5 dB, gain >= 5.5 dBic and Axial Ratio (AR)<= 1.8 dB, over the universal UHF RFID band of 840 to 955 MHz and the 3-dB AR beam-width is more than 110 degrees. Then, an improved bandpass filter based on coupled lines and a ring resonator is proposed for achieving extremely narrow frequency response. A CP filter reader antenna using this narrow bandpass filter is proposed for enhancing the reliability of the communication and reducing the cost of the microwave front end in RFID system. The filter antenna exhibits the measured 1-dB gain (gain>6.4 dBic) bandwidth from 905 to 930 MHz and RL >= 15 dB, AR <= 1.4 dB in the band.

• 出版日期2014-8
• 单位北京大学; 湖南大学