Characterizing FR-4 Dielectric Constant Using Antenna Resonant Frequency

摘要

The use of antenna resonance for characterizing the dielectric constant of an FR-4 substrate is demonstrated. The maximum error in predicting the resonant frequency of a patch antenna by this method is found to be three percent while minimum error is 0.3 percent. This is within the range of typical impedance control (10 percent) provided by PCB manufacturers. A step-by-step guideline and formula are provided. This approach is inexpensive and involves the straightforward measurement of return loss.