A Circular Microstrip Antenna Sensor for Direction Sensitive Strain Evaluation

Area of Science:

• Electrical Engineering
• Materials Science
• Mechanical Engineering

Background:

• Structural health monitoring (SHM) systems require reliable methods for assessing material integrity.
• Traditional strain gauges have limitations in measuring multi-directional stress.
• Microstrip antennas offer potential as compact, non-contact sensors.

Purpose of the Study:

• To investigate a circular microstrip antenna as a sensor for evaluating stress and strain.
• To develop a sensor capable of determining both the magnitude and direction of applied stress.
• To explore the feasibility of using microstrip antennas as an alternative to rosette strain gauges.

Main Methods:

• Designing and fabricating a circular microstrip antenna sensor.
• Measuring the reflection coefficient (S11) to correlate with strain.
• Analyzing resonant frequency shifts under applied stress.
• Utilizing numerical modeling and experimental verification for directional characteristics.

Main Results:

• The microstrip sensor demonstrated sensitivity up to 1 MHz/100 MPa.
• Two distinct resonant frequencies were analyzed, revealing different current distributions.
• Directional characteristics were determined, enabling stress direction and magnitude measurement.
• The sensor's performance was validated through numerical and experimental methods.

Conclusions:

• The proposed circular microstrip antenna is effective for stress evaluation in SHM.
• This sensor can determine both the magnitude and direction of stress, overcoming limitations of previous methods.
• The microstrip antenna sensor presents a viable alternative to rosette strain gauges for deformation measurement.