Table 1.

Comparison between the measured permittivities of the samples under test and using (4) and the actual values taken from the commercial datasheets.

Sample	Meas. ${\mathit{f}}_{\mathbf{d}}$ (GHz)	Calc. ${\mathit{\epsilon }}_{\mathbf{d}}$	Meas. ${\mathit{\epsilon }}_{\mathbf{r}}$	Actual ${\mathit{\epsilon }}_{\mathbf{r}}$	Error (%)
RT5880	$0.21$	$1.258$	$2.258$	$2.2$	$2.6$
RO4350	$0.347$	$2.44$	$3.44$	$3.55$	3
FR4	$0.44$	$3.55$	$4.55$	$4.7$	$3.2$
RO3006	$0.58$	$5.84$	$6.84$	$6.5$	$5.2$
RO6010	$0.7325$	$9.57$	$10.57$	$10.7$	$1.2$