Electromechanical filter cells

Each cell includes two longitudinally vibrating cylindrical resonators and a flexurally vibrating coupler connected between the two resonators. The diameter of the coupler is defined by the expression: dc = +TR wherein: dr is the diameter of the resonators lc is the length of the coupler OMEGA +=f+/fo is the upper relative of the band of frequencies to be transmitted, f+ the uper frequency of said band and fo the tuning frequency of the resonators with lo the length of the coupler corresponding to a quarter wave effect dr+=2 pi nrm OMEGA + where m is the order of the vibration mode of the resonators and nr=lr/ lambda o with lr the length of the resonators and lambda o the wavelength at the tuning frequency of the resonators in longitudinal vibration.