A Miniaturized Study Of High Divided Microstrip Branch-line Coupler

With the developing of the third mobile telecommunication, the frequency is becoming higher and higher.Not only the stability,high reliability of communication and beyond the disturbing well is needed, but it needs to be changed suitably with the society,that the radio communication system should become lighter and smaller. Certainly the equipment of the system of the radio communication also needs to be lighter and smaller. The micro-strip branch-line coupler is an important device in the microwave circuit, it is applied widely by the blue-tooth system of the cell-telephone and the radio frequency top part of the base. It is very important for radio communication to study the miniature of the micro-strip branch-line coupler.Using the stub to miniaturize the microstrip branch-line coupler is mostly used.And equating the transmission to be∏and T transmission line is two main methods.In this thesis,we mainly use the∏transmission-line to miniaturize the microstrip branch-line coupler.The branch-line is meandered in the lOdB coupler.Lastly the miniaturized microstrip branch-line coupler is completed.The size of the coupler using∏transmission line firstly miniaturized is 50% less than the original 10dB micro-strip branch-line coupler; After the branch-line is meandered, the size of the branch-line coupler is 65% less than the original 10dB micro-strip branch-line coupler. According to the frequency graph of simulation, the feasibility of the miniature is validated.