A novel type of radio frequency identification (RFID) reader antenna is proposed for mobile ultra-high frequency (UHF) RFID device. By folded-dipole loop structure with parasitic element, a small antenna size of 31 * 31 * 1.6 mm 3 is achieved. The antenna with different parasitic element size can work on different UHF RFID bands. The antenna prototype is fabricated and the measured bandwidth is around 13.5 MHz (915.5-929 MHz), which covers the China RFID Band (920-925 MHz). The measured reading distance achieves 65 mm with the near-field RFID tag and 1.17 m with the far-field tag. The measurement agrees well with simulated result and shows that antenna is desirable for both near-field and far-field UHF RFID applications.

Abstract-In this paper, a novel technique for planar inverted-F antenna (PIFA) with broadband circular polarization and pattern diversity is proposed. A defeated ground structure (DGS) has achieved broadband circular polarized (CP) PIFA by using a square branch at the ground corner with arrow-shaped slot. The pattern diversity PIFA system consists of two CP PIFAs placed symmetrically on the diagonal of DGS. Furthermore, the DGS improves port-to-port isolation by using another smaller square branch at the opposite ground corner. Finally, a prototype is fabricated and measured. The measured results agree well with simulation, and show 10-dB matching bandwidth of 16.3% (825-986 MHz), 3-dB axial ratio (AR) bandwidth of 15.5% (830-982 MHz), and 25-dB isolation bandwidth of 12.4% (848-968 MHz), which shows suitability for radio-frequencyidentification (RFID) application.

In this paper, a compact near field reader antenna is proposed for ultra-high frequency (UHF) radio frequency identification (RFID) applications. The antenna structure is composed of two split-ring-resonators (SRRs) and miniaturized to a special small size of 21 * 21 * 1.6 mm 3 for mobile RFID application. The measured bandwidth of antenna prototype is 13 MHz (914.5-927.5 MHz) with reflection coefficient less than −10 dB, which covers the China RFID band II (920-925 MHz). Simulation shows that the proposed antenna achieves a strong and uniform magnetic field distribution in the near field region, and the reading range is up to 42 mm with near field RFID tag. Through modifying the parameters of SRRs, the antenna can operate on different UHF RFID bands (Europe band, China band I&II etc.).

In this paper, a novel fractal PCB power plane based on leaf vein fractal structure is developed. The technique introduced here not only provide noise suppression over a wide range of frequencies, but also improve IR drop and Swiss Chess structure effect (high resistance metal areas because of distributed vias and solders and leading to the voltages or currents to the circuit elements lower than design demand).