Crack Sensoring Devices Construction by Means of Microwave Resonant Circuit Design

Microwave engineering applications related to crack sensoring may have some implications and obstacles; for instance, high cost, adaptive design and external circuitry coupling. This paper presents simulated and practical results of a band-pass filter, constituted of two quarter-wavelength spaced open circuit stubs, connected in shunt along a transmission line, which acts as a series resonant circuit. The device is used as a crack sensor, using flexible substrates. Comparison is made to check which substrate fits best this application.