Integrated resonant microbeam sensor and transistor oscillator

Claim 2

A transistor resonant integrated microbeam structure comprising: a beam situated in a substrate and connected to a reference terminal, said beam having a first end and a second end fastened to the substrate, said beam having a tension or compression between the first and second ends and caused by bending of the substrate due to a magnitude of a physical parameter being measured, and said beam having a resonant frequency affected according to an amount of tension or compression of said beam, the resonant frequency indicating the magnitude of the physical parameter; a first electrode situated on a first side of said beam, such that when said beam vibrates, a distance between said beam and said first electrode varies in synchronism with the resonant frequency, resulting in a first capacitance between said first electrode and said beam that varies inversely with the distance between said first electrode and said beam; a second electrode situated on the first side of said beam, a distance between said beam and said second electrode varies proportionally to the distance between said beam and said first electrode, and a second capacitance between said second electrode and said beam varies in phase with the first capacitance; and a non-inverter having an input connected to said first electrode and an output connected to said second electrode; and wherein said non-inverter comprises: a first transistor having a first terminal connected to said first electrode, a second terminal connected to the reference terminal, and a third terminal; and an inverter having an input terminal connected to the third terminal of said transistor and having an output terminal connected to said second electrode.

Claim 3

The microbeam structure of claim 1 further comprising a feedback impedance having a first terminal connected to the first terminal of said first transistor and having a second terminal connected to said second electrode.

Claim 4

The microbeam structure of claim 2 wherein: said first electrode is a sense electrode; and said second electrode is a driver electrode.

Claim 5

The microbeam structure of claim 3 wherein said inverter comprises: a second transistor having a first terminal connected to the third terminal of said first transistor, having a second terminal connected to the first terminal of said second transistor, and having a third terminal connected to a voltage terminal; a third transistor having a first terminal connected to said second electrode, having a second terminal connected to the second terminal of said second transistor, and having a third terminal connected to the voltage terminal; and an impedance having a first terminal connected to the first terminal of said third transistor and having a second terminal connected to the reference terminal.

Claim 6

A transistor resonant integrated microbeam structure comprising: a first beam situated in a substrate and connected to a reference terminal, said first beam having a first end and a second end fastened to the substrate, said first beam having a tension or compression between the first and second ends which is caused by a bending of the substrate due to a magnitude of a physical parameter being measured, and said first beam having a resonant frequency dependent upon an amount of tension or compression of said first beam, the resonant frequency indicating the magnitude of the physical parameter; a second beam situated proximate to said first beam and connected to the reference terminal, said second beam having a first end and a second end fastened at the first and second ends of said first beam, said second beam being parallel to and at a distance from said first beam, said second beam having a tension or compression like that of said first beam, said second beam being mechanically coupled to said first beam so when said first beam vibrates, said second beam vibrates at a resonant frequency that is the same as the resonant frequency of said first beam, and vibrates 180 degrees out of phase relative to said first beam; a first electrode situated proximate to a first side of said first beam which is opposite to a second side of said first beam that is proximate to said second beam, said first electrode at a first distance that varies with respect to said first beam when said first beam vibrates, and said first electrode having a first capacitance relative to said first beam, that varies inversely to the first distance, at the resonant frequency of said first beam; a second electrode situated proximate to a first side of said second beam opposite to a second side of said second beam that is proximate to said first beam, said second electrode at a second distance that varies with respect to said second beam when said second beam vibrates, and said second electrode having a second capacitance relative to said second beam, that varies inversely to the second distance, at the resonant frequency of said second beam; and a noninverter having an input connected to said second electrode and an output connected to said first electrode; and wherein said noninverter comprises: a first transistor having a first terminal connected to said second electrode, a second terminal connected to the reference terminal and having a third terminal; a load impedance having a first terminal connected to the third terminal of said first transistor and having a second terminal connected to a first voltage terminal; and an inverter having an input terminal connected to the third terminal of said first transistor and having an output terminal connected to said first electrode.

Claim 7

A transistor resonant integrated microbeam structure comprising: a first beam situated in a substrate and connected to a reference terminal, said first beam having a first end and a second end fastened to the substrate, said first beam having a tension or compression between the first and second ends which is caused by a bending of the substrate due to a magnitude of a physical parameter being measured, and said first beam having a resonant frequency dependent upon an amount of tension or compression of said first beam, the resonant frequency indicating the magnitude of the physical parameter; a second beam situated proximate to said first beam and connected to the reference terminal, said second beam having a first end and a second end fastened at the first and second ends of said first beam, said second beam being parallel to and at a distance from said first beam, said second beam having a tension or compression like that of said first beam, said second beam being mechanically coupled to said first beam so when said first beam vibrates, said second beam vibrates at a resonant frequency that is the same as the resonant frequency of said first beam, and vibrates 180 degrees out of phase relative to said first beam; a first electrode situated proximate to a first side of said first beam which is opposite to a second side of said first beam that is proximate to said second beam, said first electrode at a first distance that varies with respect to said first beam when said first beam vibrates, and said first electrode having a first capacitance relative to said first beam, that varies inversely to the first distance, at the resonant frequency of said first beam; a second electrode situated proximate to a first side of said second beam opposite to a second side of said second beam that is proximate to said first beam, said second electrode at a second distance that varies with respect to said second beam when said second beam vibrates, and said second electrode having a second capacitance relative to said second beam, that varies inversely to the second distance, at the resonant frequency of said second beam; and a noninverter having an input connected to said second electrode and an output connected to said first electrode; and wherein said noninverter comprises: a first transistor having a first terminal connected to said second electrode, a second terminal connected to the reference terminal and having a third terminal; a load impedance having a first terminal connected to the third terminal of said first transistor and having a second terminal connected to a first voltage terminal; and an inverter having an input terminal connected to the third terminal of said first transistor and having an output terminal connected to said first electrode.

Claim 8

The microbeam structure of claim 5 further comprising a feedback impedance having a first terminal connected to the third terminal of said first transistor and having a second terminal connected to the first terminal of said first transistor.

Claim 9

The microbeam structure of claim 5 wherein: said first electrode is a driver electrode; and said second electrode is a sensor electrode.

Claim 10

The microbeam structure of claim 7 wherein said inverter comprises: a second transistor having a first terminal, having a second terminal connected to the output terminal of said inverter and having a third terminal connected to a second voltage terminal; a third transistor having a first terminal connected to the first terminal of a said second transistor, having a second terminal connected to the reference terminal, and having a third terminal connected to the second terminal of said second transistor; and an input impedance having a first terminal connected to the input terminal of said inverter and having a second terminal connected to the first terminal of said second and third transistors.

Claim 11

A transistor resonant integrated microbeam structure comprising: a first beam, capable of vibrating, situated in a substrate; a second beam, capable of vibrating, situated in the substrate, adjacent to said first beam; a third beam, capable of vibrating, situated in the substrate, adjacent to said second beam; a first electrode, proximate to said first beam, having a capacitance relative to said first beam, the capacitance having a value that varies with vibrating movement of said first beam; a second electrode, proximate to said second beam, having a capacitance relative to said second beam, the capacitance having a value that varies with vibrating movement of said second beam; a third electrode, proximate to said third beam, having a capacitance relative to said third beam, the capacitance having a value that varies with vibrating movement of said third beam; and an inverter having an input connected to said first and third electrodes and an output connected to said second electrode; and wherein: said first, second and third beams have ends fastened to the substrate and connected to a reference terminal, have a resonant frequency that varies relative to a tension or compression applied at the ends to said first, second and third beams, the tension or compression caused by a physical phenomenon having a magnitude, and the resonant frequency being an indication of the magnitude of the physical phenomenon.

Claim 12

A transistor resonant integrated microbeam structure comprising: a first beam, capable of vibrating, situated in a substrate; a second beam, capable of vibrating, situated in the substrate, adjacent to said first beam; a third beam, capable of vibrating, situated in the substrate, adjacent to said second beam; a first electrode, proximate to said first beam, having a capacitance relative to said first beam, the capacitance having a value that varies with vibrating movement of said first beam; a second electrode, proximate to said second beam, having a capacitance relative to said second beam, the capacitance having a value that varies with vibrating movement of said second beam; a third electrode, proximate to said third beam, having a capacitance relative to said third beam, the capacitance having a value that varies with vibrating movement of said third beam; and an inverter having an input connected to said first and third electrodes and an output connected to said second electrode; and wherein: said first, second and third beams have ends fastened to the substrate and connected to a reference terminal, have a resonant frequency that varies relative to a tension or compression applied at the ends to said first, second and third beams, the tension or compression caused by a physical phenomenon having a magnitude, and the resonant frequency being an indication of the magnitude of the physical phenomenon.

Claim 13

The microbeam structure of claim 9 wherein said inverter comprises: a transistor having a first terminal connected to the input of said inverter, a second terminal connected to a reference terminal and a third terminal connected to the output of said inverter; and a load impedance having a first terminal connected to the third terminal of said transistor and having a second terminal connected to a voltage terminal.

Claim 14

The microbeam structure of claim 10 wherein: said first and third electrodes are capacitive sensing electrodes that sense vibrating movement of said first and third beams, respectively; said second electrode is an electrostatic driving electrode that drives said second beam to vibrating movement at the resonant frequency; and said first and third beams are driven to vibrating movement at the resonant frequency through a mechanical coupling because of proximity to said second beam when vibrating.

Claim 15

The microbeam structure of claim 11 further comprising a feedback resistor having first and second terminals connected to the first and third terminals, respectively, of said transistor.

Claim 16

The microbeam structure of claim 12 wherein: said transistor is an N-channel field effect transistor; and the first, second and third terminals of said transistor are a gate, a source and a drain, respectively.

Claim 17

The microbeam structure of claim 12 wherein: said transistor is a bipolar transistor; and the first, the second, and third terminals of said transistor are a base, an emitter and a collector, respectively.