SAW Technology

Benefits & Competing Technologies

Read further about the benefits of SAW Sensor Technology and how it compares to competing technologies

Preserve System Integrity

Unlike other force and torque sensors, SAW technology measures microstrain, enabling measurement without compromising the mechanical integrity of the system. Simplifying the measurement of existing components.

Higher Measurement Accuracy

SAW torque sensors can deliver better than 1% of full-scale accuracy over the temperature range -40°C to +150°C together with low hysteresis and drift. Enabling improved control and performance.

High Speed Sensing

High sample rate of 2 kHz enabling for example, torque measurement in engines and powertrains every few degrees of shaft or disk rotation (eg. every 3 degrees at 1000 rpm).

Insensitive to Magnetic Fields

Many automotive applications require torque sensing close to electric motors and solenoids. This is problematic for some other types of sensor technology.

Measure moving components

Measures torque, thrust, pressure and temperature on rotating or moving components.

No wear and tear

Non-contact offers long mechanical life and are maintenance free as they don’t use parts which will wear and tear.


There are no wires or slip rings between the sensor and electronics.


No electrical power is applied to or generated by the sensor, the energy exciting the SAW sensor is provided by the interrogating RF pulse.


A typical Transense SAW sensor is an intrinsically a low cost device. It contains no electronic components.

Low Mass

A typical SAW sensor weighs less than 1 gram. This is very beneficial in motorsport applications where every gram counts

Small Size

Enables the addition of one or two sensing elements to existing components such as shafts or disks with only minimal intrusion or modification.

No special materials are required

Unlike other technologies the SAW torque sensor can be mounted on any type of steel even other types of metal.

Mechanically Rugged

SAW sensors have demonstrated considerable tolerance to high shock loads, high speed centripetal forces, vibration and chemical resistance.

Measurement of Surface Strain (Strain Gauge Sensors)

This has been the conventional method for measuring rotating torque by using a piezoresistive (a material that changes resistivity depending on strain) strain gauge attached to the rotating shaft. Changes in strain, because of torque, are recorded as variations in an electric signal.


Measurement of the Twist Angle (Displacement Sensors)

This method typically uses a pair of identical toothed disks attached at opposite ends of a portion of the shaft enables a ‘twist angle’ to be determined from the phase difference between them through an optical or magnetic measurement, which in turn enables torque to be calculated.


Measurement of Magnetic Fields (Magnetoelastic/Magnetostrictive Sensors)

This method for torque readings is achieved through the measurement of changes in magnetic permeability or the magnetic field that occur on regions of the shaft surface because of torsional stress from the applied torque. These variations in permeability or the generated magnetic field are measured by encircling the shaft in some pattern of coils of wires and observing differences in induced voltages.


Strain Gauge Sensors SAW SensorsSAW Sensors Displacement Sensors Magnetoelastic/ Magnetostrictive Sensors
Non-contact NO ₁ YES YES YES
Torsionally stiff NO YES NO YES
Independent of T without need for compensation NO NO In some cases NO
Radially Mountable NO NO YES NO
Package-able in motorsport race conditions NO YES NO YES
Suitable for use is liquid environments i.e. oil NO YES NO NO
Frequency response 1kHz Possible up to 8Kz, normally 1.7 kHz 500 Hz 2 kHz
Operational Speeds NK ₂ 0 – 30,000 rpm NK ₂ 0 - 20,000 rpm
Operational Temperature range NK ₂ -40°C to+150°C NK ₂ +20°C to +130°C
Static and Dynamic measurement NO YES NO YES
Suitable for medium to high volume manufacture NO YES YES NO
Suitability to a variety of steels and non-ferrite materials YES YES YES NO

1 - To have a non-contact capability requires inductive coupling, slips rings or electronic shaft telemetry
2 - NK = Not Known

SAW Technology



Questions and answers on our patented Transense Torque and Temperature sensors