DEFECTED CONCRETE POST DETECTION THROUGH ANTENNA ARRAY COUPLING EFFECT

Abstract

In this paper, a proposed defected concrete post detection system is introduced. The proposed system consists of two compact microstrip broad side antenna arrays resonating at 1 GHz with dimensions of 45 cm by 13.2 cm for each antenna array and a weight of 800 gm for both antenna arrays. Also a portable vector network analyser is used for scattering parameters measurement purpose. For size comparison purpose, a conventional microstrip antenna array is designed and compared with the proposed one at the same resonant frequency. A size reduction of 23.4 % is obtained. The proposed antenna array directivity of 10.5 dBi and 3 dB beam width of 30.7 are obtained which are suitable for the concrete post defect detection. The detection principle is relied on the coupling between the two antenna array elements. Three cases are considered for simulation and measurement, air, good concrete block and defected concrete block. A 10 dB difference in coupling was obtained between the presence and the absence of the defect in the concrete block. A proposed measurement system is introduced. Good agreement is obtained between measured and simulated results. The proposed defected concrete post detection system is noticed to be light weight, simple, cheap and has a reasonable accuracy level.

Keywords

• Microstrip antenna
• Broad side antenna array
• Compact antenna array
• S-parameters
• Non-destructive test.