Wireless ultrasound sensor

Abstract

A wireless ultrasound sensor 404 for non-destructive testing of a test object 502 , the sensor comprising: an ultrasound transducer 406 ; a first induction coil 408 , electrically coupled to the ultrasound transducer; a second induction coil 414 , electrically coupled in parallel with the first induction coil; wherein the first and second induction coils are arranged to enable the transducer to be inductively operated by a remote device 504 ; and wherein the diameter of the second induction coil is greater than the diameter of the first induction coil.

1 . A wireless ultrasound sensor for non-destructive testing of a test object, the sensor comprising:
 an ultrasound transducer;   a first induction coil, electrically coupled to the ultrasound transducer;   a second induction coil, electrically coupled to the ultrasound transducer in parallel with the first induction coil;   wherein the first and second induction coils are arranged to enable the transducer to be inductively operated at an operation frequency thereof by a remote device; and   wherein the outer diameter of the second induction coil is greater than the outer diameter of the first induction coil.   
     
     
         2 . A wireless ultrasound sensor according to  claim 1  wherein the outer diameter of the second induction coil is greater than the outer diameter of the first induction coil by a factor of at least 1.1. 
     
     
         3 . A wireless ultrasound sensor according to  claim 1  wherein the transducer, the first induction coil and the second induction coil are mounted in a substantially coaxial arrangement. 
     
     
         4 . A wireless ultrasound sensor according to  claim 1  wherein the first induction coil and the second induction coil are mounted in substantially the same plane. 
     
     
         5 . A wireless ultrasound sensor according to  claim 1  wherein the first induction coil has an inductance such that the first induction coil and the ultrasound transducer form a circuit with a resonant frequency that matches an optimal operating frequency of the ultrasound transducer. 
     
     
         6 . A wireless ultrasound sensor according to  claim 1  wherein the first induction coil has an inductance between 0.05 μH to 10 μH. 
     
     
         7 . A wireless ultrasound sensor according to  claim 1  wherein the second induction coil has an inductance between 0.1 μH to 20 μH. 
     
     
         8 . A method of producing an ultrasound sensor for non-destructive testing of a test object, comprising:
 providing a first induction coil having a first outer diameter;   providing a second induction coil having an outer diameter which is greater than the first outer diameter;   electrically coupling the first induction coil to the ultrasound transducer; and   electrically coupling the second induction coil to the ultrasound transducer in parallel with the first induction coil.   
     
     
         9 . A method of  claim 8 , including a step of calculating the inductance value required to operate the ultrasound transducer at an operating frequency and whereby the steps of providing the first and second induction coils comprise:
 providing a first induction coil having the required inductance value; and providing a second induction coil having an outer diameter which is greater than the first diameter and which provides an inductance that substantially does not change the total inductance of the ultrasound sensor.   
     
     
         10 . A wireless non-destructive testing system comprising a wireless ultrasound sensor according to  claim 1  and an inspection wand arranged to inductively operate the wireless ultrasound sensor.