Design and realization of crystal band pass filter using discrete crystal resonators

The 4^th order Crystal band pass filter has been designed and realized at a frequency of 71.61MHz with low insertion loss, high rejection at stop band and good input-output return loss. A coupled resonator ladder topology is used to realize the filter. AT-cut High Frequency Fundamental Mode (HFFM) crystal resonators are used. Four crystal resonators are used to meet the required specification. The HC-4S/U package of crystal resonators are used in this filter. Also design is realized with the help of computer aided software ADS.