Using the formula: [ y_0 = \frac28.4\pi \cdot \arccos\left( \sqrt\frac50218 \right) ] [ y_0 = 9.04 \cdot \arccos(0.479) ] [ y_0 = 9.04 \cdot 1.07 \text radians = 9.67 \text mm ]
The thickness of the PCB. Thicker substrates generally offer better bandwidth and lower loss but can increase surface wave excitation.
An inset feed is simply a notch cut into the patch. The feed line extends into the patch to a specific depth (( y_0 )). As the feed point moves from the edge (( Z_high )) toward the center (( Z_low )), the input impedance transitions smoothly. patch antenna inset feed calculator
cap W equals the fraction with numerator c and denominator 2 f sub 0 the square root of the fraction with numerator epsilon sub r plus 1 and denominator 2 end-fraction end-root end-fraction Calculate Effective Permittivity ( epsilon sub e f f end-sub Accounts for electric fields in both air and substrate.
$$ y_0 = \fracL\pi \arccos\left(\sqrt\fracZ_0R_edge\right) $$ Using the formula: [ y_0 = \frac28
Account for the thickness of the copper for high-frequency designs.
Your goal is to find a point along the length of the patch where the impedance is exactly (or whatever your system impedance is). That point is the inset point . The feed line extends into the patch to
If you blindly follow the formula, you might still get a Voltage Standing Wave Ratio (VSWR) of 2:1 instead of 1.2:1. Why?
Input ( Z_target=50, R_edge=190 ): [ y_0 = \frac12.2\pi \cdot \arccos(\sqrt50/190) = 3.88 \cdot \arccos(0.513) = 3.88 \cdot 1.03 = 4.0 \text mm ]