Systems for Characterizing Resonance Behavior of Magnetostrictive Resonators

Abstract

Illustrative embodiments of systems for characterizing resonance behavior of magnetostrictive resonators are disclosed. In one illustrative embodiment, an apparatus may comprise a first channel including one or more driving coils and one or more magnetostrictive resonators, the first channel having a first impedance; a second channel having a second impedance, the second impedance differing from the first impedance by an impedance attributable to the one or more magnetostrictive resonators; a signal source configured to apply an input signal to both the first and second channels; and a signal receiver configured to generate a combined output signal in response to output signals measured from both the first and second channels.

1 . Apparatus comprising:
 a first channel including one or more coils and one or more magnetostrictive resonators, the first channel having a first impedance;   a second channel having a second impedance, the second impedance differing from the first impedance by an impedance attributable to the one or more magnetostrictive resonators;   a signal source configured to apply an input signal to both the first and second channels; and   a signal receiver configured to generate a combined output signal in response to output signals measured from both the first and second channels.   
     
     
         2 . The apparatus of  claim 1 , wherein the one or more magnetostrictive resonators comprise a plurality of magnetostrictive resonators. 
     
     
         3 . The apparatus of  claim 1 , wherein the one or more coils surround a first portion of a sample and the one or more magnetostrictive resonators are disposed in the first portion of the sample. 
     
     
         4 . The apparatus of  claim 3 , wherein the one or more magnetostrictive resonators each comprise a sensing element that reacts with a target species in the sample. 
     
     
         5 . The apparatus of  claim 3 , wherein the second channel includes one or more coils surrounding a second portion of the sample and no magnetostrictive resonators are disposed in the second portion of the sample. 
     
     
         6 . The apparatus of  claim 5 , wherein the second channel further includes a linear element electrically coupled to the one or more coils of the second channel. 
     
     
         7 . The apparatus of  claim 1 , wherein the first channel further includes a linear element electrically coupled to the one or more coils of the first channel. 
     
     
         8 . The apparatus of  claim 1 , wherein the signal source is configured to sweep the input signal over a range of frequencies including a resonance frequency of the one or more magnetostrictive resonators. 
     
     
         9 . The apparatus of  claim 1 , wherein the combined output signal is a difference between the output signals measured from both the first and second channels. 
     
     
         10 . The apparatus of  claim 1 , wherein the combined output signal is a ratio between the output signals measured from both the first and second channels. 
     
     
         11 . The apparatus of  claim 1 , further comprising a processor configured to determine a resonance behavior of the one or more magnetostrictive resonators in response to the combined output signal. 
     
     
         12 . The apparatus of  claim 11 , wherein the resonance behavior of the one or more magnetostrictive resonators comprises a resonance frequency of the one or more magnetostrictive resonators. 
     
     
         13 . The apparatus of  claim 11 , wherein the resonance behavior of the one or more magnetostrictive resonators comprises a quality factor of the one or more magnetostrictive resonators. 
     
     
         14 . A method comprising:
 applying an input signal to a first channel including a magnetostrictive resonator, the first channel having a first impedance;   applying the input signal to a second channel having a second impedance,   wherein the second impedance differs from the first impedance by a magnetostrictive resonator impedance;   generating a combined output signal in response to output signals measured from both the first and second channels; and   determining a resonance behavior of the magnetostrictive resonator in response to the combined output signal.   
     
     
         15 . The method of  claim 14 , wherein applying the input signal to the first channel and applying the input signal to the second channel are performed simultaneously. 
     
     
         16 . The method of  claim 14 , wherein generating the combined output signal comprises subtracting a second channel output signal from a first channel output signal. 
     
     
         17 . The method of  claim 14 , wherein generating the combined output signal comprises calculating a ratio between a first channel output signal from a second channel output signal. 
     
     
         18 . A method comprising:
 applying a stepped electrical signal to one or more driving coils to generate a first time-varying magnetic field;   measuring a decaying electrical signal from one or more pick-up coils, wherein the one or more pick-up coils receive a second time-varying magnetic field generated by a plurality of magnetostrictive resonators in response to the first time-varying magnetic field; and   determining a resonance frequency of each of the plurality of magnetostrictive resonators using a Fast Fourier Transform of the decaying electrical signal.   
     
     
         19 . The method of  claim 18 , wherein applying the stepped electrical signal to one or more driving coils comprises applying an electrical pulse having a width that is smaller than each period corresponding to the resonance frequencies of the plurality of magnetostrictive resonators. 
     
     
         20 . The method of  claim 18 , wherein measuring the decaying electrical signal from one or more pick-up coils comprises using first and second pick-up coils that are wound in opposite directions.