microstrip dipole antenna

Hi,all
I'm working on a project about designing of UHF RFID tag antenna, I've searched
many articles,but few were found on microstrip dipole antenna, lots of dipoles antenna are not the type of microstrip. because we hope the back of the antenna is metal ground , that the antenna could be little affected by metal ,water and so on.

another ,I read some books, I noticed the impendance of microstri dipole antenna .since our tag chip's input impedance is difference 50Ω, so is it quite hard to match the microstrip antenna to the tag chip?

Need your help ,thanks a lot！
L.J.Zheng

If you review some of the various books designated to microstrip antenna design, you'll find that none of them mentions a microstrip dipole antenna. To my opinion it would be a contradiction in terms, cause a microstrip antenna has a main vertical E-field component, that can't exist in a dipole antenna. If you put a dipole structure on a ground plane, it's no longer a dipole.

Microstrip respectively patch antennas are often used in RFID applications. I've no practical experiences in the UHF RFID field and don't want to suggest a particular design, but you can find plenty of them in literature.

Impedance matching can be done either by microstrip or lumped element networks. Because RFID is always small bandwidth, matching can be calculated with classical smith chart method.

http://www.urel.feec.vutbr.cz/~raida...er-4/4_4B.html

Unlike the presented EM theory textbook, the majority of antenna textbooks seem to avoid designating the structure a dipole. But I think, it's of limited purpose, to discuss the appropriate usage of technical terms. The more interesting question is, if the structure has useful properties as a RFID antenna.

Hi,vfone, I've read the website you refered, the function is so complexed,so I can't get more information from it, Thanks anyway.

Hi,FVM, because our tag chip's output ports are diference,so the use of dipole is convient for match(not need a balun), and the good of microstrip antenna can greatly decrease the effects of metal,water,human body...which behind the back of
the tag.... .I have thought about lump match,that's mabye the last way. Thanks!

See this paper.
Ready made Printed Dipole Antenna
I hope this Helps you

Abhishekabs

I agree with FvM that the term "microstrip dipole antenna" is really confusing, since I have got little info about it in classical antenna books. However, what I wanted to add here is that there has been one antenna proposed by the rfid group in Kansas Univ. The antenna works as a dipole alone and can be viewed as microstrip antenna once placed on metals. I think the design is interesting.