RFID标签天线的文献语录.docx

1、RFID标签天线的文献语录RFID标签天线的文献语录A new resonant frequency tunable RFID tag antenna design.pdf无*A Novel Broadband UHF RFID Tag Antenna Mountable on Metallic Surface.pdfTo some extents, the tag antenna is considered as the most important part which directly affects the communication between the reader and ta

2、g in an RFID system. However, it is hard to design a tag antenna for passive UHF RFID applications because of two main obstacles. First, a microchip has a high quality factor because of its small resistance and large capacitance reactance at its terminals, which makes it not easy to attain the conju

3、gate match between the tag antenna and the microchip or to achieve a wideband characteristic. Secondly, the performance of a tag antenna varies when it is mounted on different objects. Especially, metallic objects which are usually tagged in RFID applications seriously degrade the terminal impedance

4、 matching, bandwidth, radiation efficiency and readable range of the tag antenna 2.The shorting strips are used to achieve more balanced current distributions on the patches.The main direction of electric field on the patches is along with the x-axis and the currents along with y-axis are smaller, w

5、hich contributes to a good cross-polarization performance.The conjugate match between the antenna and the microchip can be tuned by adjusting the perimeter and the line width of the loop of the T-matching network. An electrical coupling is generated around the gap between the two patches, which incr

6、eases the bandwidth of the antenna. The bandwidth of the proposed antenna can be controlled in a certain degree by alternating the width of this gap or the line width of the two shorting strips. Eventually, the proposed antenna is optimized to have the conjugate match between itself and the microchi

7、p. Also, some spaces among the patches and the T-matching network are reserved for tuning the T-matching network to get an impedance matching without modifications of the two patches in the case of other microchip is chosen.The half power bandwidth (return loss -3dB)*A novel small antenna for passiv

8、e RFID transponder.pdfThese early studies show that small antennas are constrained in their behaviour by a fundamental limit: the smaller the maximum dimension of the antenna, the higher is its Q, or equivalently, the narrower is its bandwidth. Accordingly, the art of antenna miniaturisation is alwa

9、ys an art of compromise among size, bandwidth, and efficiency (gain).Impedance matching between transponder ASIC and antenna is critical on overall RFID system performance. Namely the mismatch very strongly affect a read range a maximum operating distance between interrogator and transponder. Becaus

10、e the power radiated by interrogator is rather limited due to certain safety regulations and other legislation. And passive RFID transponder extracts its operating power by rectifying interrogation signal delivered by the antenna.Rectifier circuit is a part of ASIC and comprises diodes (such as Scho

11、ttky diodes) and capacitors, resulting in the complex input impedance with substantial capacitive reactance. Typically the impedance of ASIC comes to a few or tens of active Ohms and a few hundreds of reactive (capacitive) Ohms. Thus the ratio of the reactance to the resistance is very high.One conv

12、entional matching technique in such a situation is an implementation of additional separate matching circuit based on inductors. However, a conventional way is now problematic because it unacceptably increases production costs. Moreover, a separate matching circuit causes extra losses that eventuall

13、y also strongly reduce system performance. Consequently, the antenna impedance should be matched directly with ASIC of the transponder.*Analysis and design of a UHF RFID tag antenna with a Split Ring Resonator.pdfFor UHF ranges, the dipole-like tags which are mostly used in many applications are too

14、 big to attach to a small object. So there are lots of studies about small tag antennas with meander type line. However most of the tags are suffer from a narrow bandwidth, low gain, low radiation efficiency, and hard control of the tag antenna impedance.*Antenna design for UHF RFID tags: a review a

15、nd a practical application.pdf 至少读5遍 A passive back-scattered RFID system operates in the followingway. Abase station (reader) transmits a modulated signal with periods of unmodulated carrier, which is received by the tag antenna. The RF voltage developed on antenna terminals during unmodulated period is converted to dc. This voltage powers up the chip, which sends back the information by