Wideband and Low Shape Factor Frequency Band Rejection Module and Filter Bank Module using Surface Acoustic Wave Resonator

摘要

PURPOSE: A filter bank module and a broadband low profile band attenuation module which uses a surface acoustic wave resonator are provided to maximize an isolation degree between different kinds of services such as WiBro(Wireless Broadband Internet), WCDMA(Wideband Code Division Multiple Access), LTE(Long Term Evolution), and CDMA 800(Code Division Multiple Access 800), thereby minimizing frequency interference of other providers within the same service. CONSTITUTION: A band attenuation module comprises a first low-pass filter(3a), a surface acoustic wave notch resonance filter(3b), a second low-pass filter(3c), and impedance matching devices(3d,3e). The first low-pass filter and second low-pass filter are comprised of a capacitor and an inductor in order to eliminate a different kind of services in an input end and output end. The surface acoustic wave notch resonance filter attenuates only a frequency band which is desired to be eliminated. The second low-pass filter is comprised of the inductor and capacitor in order to suppress interference of the different kind of services inputted in a reverse direction. The impedance matching device is installed between each low-pass filter and surface acoustic wave notch resonance filter.