Fbar (fbar) And Modeling

Radio frequency transceiver circuits have a very broad range of applications. With the development of wireless communications, more and more minitype and integrational components are required. The convential microwave ceramic filters are too large and can not integrate with RFIC. The surface acoustic wave filters (SAW) can not assume high power for they are limited by the photoetch technology. As the only integrable solution for RF bandpass filters, the film bulk acoustic resonator (FBAR) filters become one of the most active research areas in wireless communications. And now, only a few giant foreign companys, such as Agilent, can produce FBARs. In China, the researchs about FBAR have just started.This paper mainly focuses on the issues of the theory model of FBAR. And the works is as follows:1. The basic theorys of piezoelectricity used in FBAR is introduced. Derived from these theroys, not only vibration equations of transverse vibration and lognitudinal vibration but also the Mason equivalent circuit and the BVD equivalent circuit are described in details.2. Two kinds of FBARs, membrane air-gap type and SMR type are presented, and we mainly fouced on the structure difference of them. And then, the procedure of depositing high c-axis oriented A1N thin film was introduced. The testing method of thin film A1N piezoelectrity is introduced.3. Based on the second piezoelectric equations, the electric impedance of lossless and lossy FBARs was both derived. Derived from Applied the BVD equivalent circuit in the FBAR analyse, we get a great agreement about the impedance curve, further more, the MBVD equivalent circuit was applied to analyse the performance of FBAR and was used to design FBAR filters4. Derived from the electronic impedance of FBAR and the MBVD equivalent circuit, we get the two kinds of figures of merit: the effective electromechanical coupling coefficient, and the quality factor. In the studies, it has been shown that the effective electromechanical coupling coefficient is exclusively related to the series and parallel resonace and thus it is used to figure out the relative bandwidth.5. Based on the electronic impedance of FBAR and the network theorys, a PCS receive band pass filter is designed and an extra attenuation pole in the transmit band was introduced by add a parallel inductance.The main target of this thesis is the method of composing FBAR RF filters as well as the analysis and design of FBARs...