Patch Antenna Calculator ((free)) -

[ \varepsilon_reff = \frac\varepsilon_r + 12 + \frac\varepsilon_r - 12\left(1 + \frac12hW\right)^-1/2 ]

[ L = \fracc2f\sqrt\varepsilon_reff - 2\Delta L ] patch antenna calculator

[ W = \fracc2f \sqrt\frac\varepsilon_r + 12 ] where (c) = speed of light ((3\times10^8) m/s) patch antenna calculator