US 11,458,504 B2 · Systems and methods of operation of capacitive radio frequency micro-electromechanical switches

Abstract

Disclosed are systems and methods of operation for capacitive radio frequency micro-electromechanical switches, such as CMUT cells for use in an ultrasound system. An RFMEMS may include substrate, a first electrode connected to the substrate, a membrane and a second electrode connected to the membrane. In some examples, there is a dielectric stack between the first and second electrodes. The dielectric stack design minimizes drift in the membrane collapse voltage. In other examples, a voltage supply coupled to an ultrasonic array compressing the CMUT cells is adapted to provide a sequence of voltage profiles to the electrodes of the CMUT cell, wherein each profile includes a bias voltage and a stimulus voltage, and wherein a polarity of each subsequent voltage profile in the sequence is opposite to the polarity of the preceding profile. In another example, there is a capacitance sensing circuit provided, which is arranged to determine a drift voltage of the CMUT cell.

Claims11

Dependent claims

An ultrasound system comprising:

an ultrasonic array of CMUT cells each CMUT cell comprising a substrate, a first electrode coupled to the substrate, a flexible membrane at least partially spatially separated from the first electrode, and a second electrode coupled to the flexible membrane;
and
a voltage supply coupled to the ultrasonic array, wherein the voltage supply is adapted to provide a sequence of voltage profiles to the electrodes of the CMUT cell, wherein each voltage profile includes a bias voltage and a stimulus voltage, wherein a polarity of at least one of the bias voltage or the stimulus voltage is reversed based on a determined drift voltage of the CMUT cell.

A method for operating a CMUT cell, the CMUT cell comprising:

a substrate;
a first electrode connected to the substrate;
a flexible membrane, wherein the flexible membrane is spatially separated from the first electrode;
and
a second electrode connected to the flexible membrane;
the method comprising performing a sequence of ultrasound generation cycles, each ultrasound generation cycle comprising:
determining a drift voltage of the CMUT cell;
providing a bias voltage to either of the electrodes of the CMUT cell, wherein the bias voltage drives the CMUT cell into collapsed mode;
providing a stimulus voltage to either of the electrodes of the CMUT cell, wherein the stimulus voltage causes a portion of the flexible membrane to vibrate at a predetermined frequency, wherein a polarity of at least one of the bias voltage or the stimulus voltage is reversed based on the determined drift voltage;
and
removing the stimulus voltage, thereby enabling the CMUT cell to receive incoming acoustic signals,
wherein the sequence comprises first cycles with a first polarity of the stimulus voltage and second cycles with an opposite second polarity of the stimulus voltage.

9 more elements

Dependencies are inferred from the claim text.

Systems and methods of operation of capacitive radio frequency micro-electromechanical switches

Life of this patent

Systems and methods of operation of capacitive radio frequency micro-electromechanical switches

Life of this patent

Abstract

Claims11