Calculation method and supported range
Transmission-line approximation: W = c/(2f)√[2/(εr+1)], effective permittivity from W/h, and the 0.412h fringing-length correction. L = c/(2f√εeff) − 2ΔL.
Supported: 1 ≤ Dk ≤ 20, h/λ₀ ≤ 0.05 and W/h ≥ 1. Thin ideal patch, uniform substrate and an electrically large ground. Feed geometry, finite ground, thickness, loss and matching are not modeled. Use these dimensions to start EM simulation and prototype tuning; no gain, S11 or bandwidth is predicted.
Technical sources
Using the result
The output is an initial resonant geometry for a thin, ideal rectangular patch. A feed point, ground size, enclosure and matching design are still required. No gain, radiation efficiency, bandwidth or return-loss result is implied by these dimensions.
From a calculation to a released design
Keep the input assumptions with the result. Recalculate when the ordered material, dielectric height, copper or operating conditions change. Confirm the final construction with the fabricator and use field simulation or measurement wherever the simplified model omits an important effect.
See the controlled-impedance guide and material selection workflow for the next checks.