Fed Microstrip Patch Antenna Calculator: Inset

[ Z_{in}(y=y_0) = Z_{edge} \cdot \cos^2\left( \frac{\pi y_0}{L} \right) ] where [ Z_{edge} \approx 90 \cdot \frac{\varepsilon_r^2}{\varepsilon_r - 1} \left( \frac{L}{W} \right) ] (for narrow patches; more accurate models use transmission line or cavity methods).

This Python function can be expanded into a full GUI or web app. inset fed microstrip patch antenna calculator

A rectangular patch antenna typically has an input impedance ranging from 100 to 300 Ohms at its radiating edge (the edge where the feed line connects). Standard RF transmission lines, however, usually have a characteristic impedance of 50 Ohms. Connecting a 50-Ohm line directly to a 200-Ohm patch edge would result in a massive impedance mismatch, causing significant signal reflection (high VSWR) and rendering the antenna inefficient. Standard RF transmission lines, however, usually have a

“Inset feed isn’t magic — it’s just moving inward until the edge’s high impedance drops to 50 ohms. This calculator does that without frying another prototype.” This calculator does that without frying another prototype

Three days later, the etched board sat on the VNA. She pressed the SMA connector gently against the inset feed point. The display flickered… then locked.

To start the calculation, you need these three primary values from your substrate and design goals: The target resonance frequency (e.g., for Bluetooth/Wi-Fi). Dielectric Constant ( ϵrepsilon sub r