MEMS-based passband filter

A method of passband filtering an AC signal, the method comprising:

• applying the AC signal to a first microelectromechanical resonator system, which comprises a first resonating beam;
• applying the AC signal to a second microelectromechanical resonator system, which comprises a second resonating beam;
• applying a DC bias signal, with a DC bias source, to the first and second resonating beams to tune an initial resonance frequency of the first and second resonating beams;
• applying a DC voltage, with a DC voltage source, only to the second resonating beam, to cause the resonating beam to buckle;
• providing a first output from the first microelectromechanical resonator system to a first input of a differential-to-single ended amplifier;
• providing a second output from the second microelectromechanical resonator system to a second input of a differential-to-single ended amplifier;
• and
• outputting, by the differential-to-single ended amplifier, a passband filtered signal of the AC signal,
• wherein the first microelectromechanical resonator system exhibits a hardening nonlinear behavior defining an upper stop frequency of the passband and the second microelectromechanical resonator system exhibits a softening nonlinear behavior, due to the applied DC voltage, defining a lower stop frequency of the passband.

A method of producing a passband filter, the method comprising:

• providing a first microelectromechanical resonator system, comprising a first resonating beam, a first drive electrode, and a first sense electrode;
• coupling an AC input signal to the first drive electrode;
• providing a second microelectromechanical resonator system, comprising a second resonating beam, a second drive electrode, and a second sense electrode;
• coupling the AC input signal to the second drive electrode;
• providing a differential-to-single ended amplifier;
• coupling a first input of the differential-to-single ended amplifier to the first sense electrode;
• coupling a second input of the differential-to-single ended amplifier to the second sense electrode;
• coupling a DC bias source to provide a DC bias signal to the first and second resonating beams to tune an initial resonance frequency of the first and second resonating beams;
• and
• coupling a DC voltage source to provide a DC voltage only to the second resonating beam, to cause the second resonating beam to buckle,
• wherein an output of the differential-to-single ended amplifier is an output of the passband filter that provides a bandpass filtered signal of the AC input signal, and
• wherein the first microelectromechanical resonator system exhibits a hardening nonlinear behavior defining an upper stop frequency of the passband and the second microelectromechanical resonator system exhibits a softening nonlinear behavior, due to the applied DC voltage, the softening nonlinear behavior defining a lower stop frequency of the passband.