The Need

It is often necessary to measure physical properties, such as temperature, strain, pressure, etc, using wireless communication between sensors and the master system. Practical constraints on sensor placement, weight, size, temperature, and lifetime requirements have led engineers to design small, light-weight sensors that operate wirelessly without battery power. During wireless transmission, a large number of multiple reflections (multi-path signal propagation) of the radio signals along the propagation path may occur, which corrupts the signal from the sensor. The propagation path can vary rapidly, such as in jet engine compressor or turbine, so the multi-path variations can be quite severe. Currently, there is a need for wireless sensors that can operate effectively in the presence of a large number of multiple reflections along the signal's propogation path.

The Technology

Researchers at The Ohio State University, led by Dr. Eric Walton, developed an innovative, wireless sensor that is designed to overcome the problems with corrupt signals in many environments. The sensor uses surface acoustic wave (SAW) time delay with a patch antenna. The reference signal created can be used to normalize the data signal to the propagation channel and extract the sensed parameter in the presence of a severe channel multi-path and rapid fading.

Commercial Applications

• Sensors and reference devices to measure temperature, mechanical stress, strain, etc.
• Aerospace engineering
• Civil engineering
• Biotechnology
• Environmental

Benefits/Advantages

• Overcomes severe channel multi-path and rapid fading
• Sensors piezoelectric structure can measure temperature, mechanical stress, strain, etc.
• Capable of transmitting at high speeds to be installed in rotating machinery