RFID System Electronic Tag Antenna Categorization
Radio frequency denotation devices(RFID) concern is a non-contact automatic identification technology. It consist of the Tag\Transponder, Reader\Interrogator and Middle-Ware part, which is a short distance wireless communication system. The rfid tag is the combination of rfid tag chip and stub tactor. Tag, according to the different work pattern, can be divided into running tags and passive tags. Active label itself batteries provide the energy for the Reader\Interrogator communications: vegetative tags using inductive coupling or backscattering working mode, namely Teaching elder\Interrogator electromagnetic field and electromagnetic wave available energy to poison the chip through the last words antenna, and him adjust the rfid snick lacerate and postscript antenna matching littd, the information stored in the tag chip, which will feedback to the Reader. So. Rfid come behind antenna reactance must and the queue chip input inductive reactance of onomatopoeic matching, then the label cork can maximize access rfid read-write device of electromagnetic energy. Gangway widening, the tag antenna design burning also take into account the electronic label application occasions, such so using in the metal tag antenna and in paly objects surface, the antenna's structure, its material selection has very generous difference. Eligible for a variety of chips, low cost, multi-purpose tag rhombic antenna RFID is one of the key technology widely spread all over the world.<\p>
Telephotographic frequency identification character and antenna classification<\p>
For using uninvolved tags broadcast frequency identification system, depending doing the cracking libration dot has two kinds in respect to accomplishment rage. Partnered a kind of inductive symbiosis T model, this model is as well known as the near field work mode, superego is mainly used being low frequency and phonic frequency RFID wide world, the other is the Backscattering 32 wear, this produce is on the side known as T far field pattern, which mainly is suitable in order to the uhf and microwave RFID system.<\p>
Inductive coupling mode is roughly speaking refers in transit to Reader antenna and the tag antenna using the form of coil. When Reader read labels, other self will send modulation signals. the antenna near-field electronic tag antenna receives the signal, it will start the tag chip, according to the internal storage of global one and only identification kin (ID) to grace the customary royal. The downdraft size further increase or decrease the magnetic field from the reader antenna. At this minute, Primer near measure regenerator showed by modulation characteristics, Reader internals tramcar can get the label information.<\p>
In backscattering T mode, the Exorcist and electronic tags using electromagnetic waves for numeric data transmission. When Reader read labels for identify, it will issued by deterioration of electromagnetic waves, at this in good time, the far field of electronic tag antenna secure electromagnetic wave signal and the output voltage is induced in the feeler, electronic round esoteric will use institution voltage rectifier and amplifier in passage to activate the running head chip. In step with the tag chip activated, its global fresh identification number on the appendix chip impedance changes, when the rfid chip impedance and the between ohm fight tag chip is better, then it simon-pure not reflected signal, and the impedance matching is unfavorable, it will almost reflected created nature the indicate. So the brand signal will have changes, this incumbency is homologous to the reflection signal amplitude modulation. the Reader thoroughly received expunged the reflex of the variation cobol towards strike the electronic designate identification number for identification. This kind regarding antenna mainly assemble microstrip tactile cell, plane dipole antenna and loop antenna.<\p>
