MEMS-based passband filter

Patent metadata

Field	Value
Publication number	US-11569796-B2
Application number	US-201716627530-A
Country	US
Kind code	B2
Filing date	Dec 5, 2017
Priority date	Jul 26, 2017
Publication date	Jan 31, 2023
Grant date	Jan 31, 2023

Abstract

A passband filter includes a first and second microelectromechanical resonator system, each including a resonating beam, a drive electrode, and a sense electrode. An AC input signal is coupled to the drive electrode of the first and second microelectromechanical resonator system. A differential-to-single ended amplifier has a first input and second input respectively coupled to the sense electrodes of the first and second microelectromechanical resonator systems. 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. A DC bias signal is coupled to the resonating beams of the first and second microelectromechanical resonator systems. 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 defining a lower stop frequency of the passband.

First claim

What is claimed is:

1. A passband filter, comprising:
a first microelectromechanical resonator system, comprising a first resonating beam, a first drive electrode, and a first sense electrode, wherein an AC input signal is coupled to the first drive electrode;
a second microelectromechanical resonator system, comprising a second resonating beam, a second drive electrode, and a second sense electrode, wherein the AC input signal is coupled to the second drive electrode;
a differential-to-single ended amplifier having a first input coupled to the first sense electrode and a second input coupled to the second sense electrode, and an output, wherein the 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;
a DC bias source configured to apply 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
a DC voltage source configured to apply a DC voltage only to the second resonating beam, to cause the second resonating beam to buckle,
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.

2. The passband filter of claim 1 , wherein the first resonating beam is a clamped-clamped beam and the second resonating beam is a cantilevered beam.

3. The passband filter of claim 1 , wherein the first and second resonating beams are clamped-clamped beams.

4. The passband filter of claim 3 , wherein the second resonating beam includes a heater and the DC voltage is applied to the heater.

5. The passband filter of claim 3 , wherein the DC voltage is applied across the second resonating beam.

6. The passband filter of claim 5 , wherein the second resonating beam is buckled and the first resonating beam is unbuckled.

7. The passband filter of claim 6 , wherein the DC voltage causes the second beam to buckle and defines the lower stop frequency of the second microelectromechanical resonator system.

8. The passband filter of claim 7 , wherein a further DC voltage is applied across the first resonating beam to define the upper stop frequency of the first microelectromechanical resonator system.

9. 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.

10. The method of claim 9 , wherein
the first microelectromechanical resonator system further comprises a first resonating beam a first drive electrode and a first sense electrode; and
the second microelectromechanical resonator system further comprises a second drive electrode and a second sense electrode.

11. The method of claim 9 , wherein the first and second resonating beams are clamped-clamped beams and the second resonating beam includes a heater, the method further comprising:
applying the DC voltage to the heater so that the second resonating beam buckles.

12. The method of claim 9 , wherein the first and second resonating beams are clamped-clamped beams, the method further comprising:
applying the DC voltage to the second resonating beam so that the second resonating beam buckles.

13. The method of claim 12 , further comprising:
defining the lower stop frequency of the second microelectromechanical resonator system by controlling the application of the DC voltage to the second resonating beam.

14. The method of claim 12 , further comprising:
defining the lower stop frequency of the second microelectromechanical resonator system and the upper stop frequency of the first microelectromechanical resonator system by controlling the application of the DC bias signal to the first and second resonating beams.

15. The method of claim 12 , further comprising:
defining the upper stop frequency of the first microelectromechanical resonator system by applying a further DC voltage to the first resonating beam.

16. 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.

17. The method of claim 16 , wherein the first resonating beam is a clamped-clamped beam and the second resonating beam is a cantilevered beam.

18. The method of claim 16 , wherein the first and second resonating beams are clamped-clamped beams.

19. The method of claim 18 , wherein the second resonating beam includes a heater and the DC voltage is applied to the heater to cause the second resonating beam to buckle.

20. The method of claim 18 , further comprising:
tuning the passband filter by adjusting the DC voltage applied to the second resonating beam.

Assignees

• Univ King Abdullah Sci & Tech

Inventors

• Ilyas Saad
• Younis Mohammad Ibrahim

Classifications

• H03H9/465 Primary

  in combination with other electronic elements · CPC title

• H03H11/04

  Frequency selective two-port networks · CPC title

• H03H3/0073

  Integration with other electronic structures · CPC title

• H03H9/2463

  Clamped-clamped beam resonators · CPC title

• H03H9/525

  for microelectro-mechanical filters · CPC title