Material Properties Characterization Based on Measurements of Reflection Coefficient and Bandwidth

The knowledge of substrate material properties is important in antenna design. We present a technique to accurately characterize thedielectric constant and loss tangent of an antenna substrate based on the measurements of antenna’s reflection coefficient and bandwidth.
In this technique, an error function is formulated by combinations of the reflection coefficient and bandwidth of measured and simulateddata, and then an optimization technique is used to efficiently search for the substrate properties that minimize the error function. Theresults show that the method is effective in retrieving the dielectric constant and loss tangent of the antenna substrate without the need ofadditional test fixtures as in conventional substrate characterization methods.