ENGINEERING ANSWER
A rectangular patch estimate is only the beginning of an antenna design. Substrate height, dielectric model, feed method, finite ground, enclosure and manufacturing tolerances affect resonance, bandwidth and radiation.
What to decide before release
Choose the band and mechanical constraints first. Use an analytical starting geometry, then simulate the complete ground and feed. Plan tuning features and measure the installed antenna, not only an isolated bare-board coupon.
Checks to put in your design brief
- Define polarization and bandwidth
- Include the enclosure and mounting
- Plan matching and radiation measurements
Important distinction
Guided wavelength is not by itself the finished patch length because fringing and feed effects are significant.
Sources & basis
Material facts follow the cited source. Design checks are preliminary guidance, not supplier process instructions.