Patch Antenna Inset Feed Calculator

[ y_0 (corrected) = y_0 + \fracW_f4 \cdot \left( \frac\varepsilon_r + 12 \right) ]

You can spend 30 minutes solving the cosine equation by hand, or you can use a specialized calculator. Modern online tools do the following in seconds:

Compare with results from commercial tools (Sonnet, HFSS) for accuracy within 5%.

Let’s run a manual example to verify a calculator: patch antenna inset feed calculator

The is not a luxury; it is a necessity for modern RF design. It transforms a tedious iterative process into a deterministic design rule.

$$ y_0 = \fracL\pi \arccos\left(\sqrt\fracZ_0R_edge\right) $$

This is the relative permittivity of your PCB material (e.g., FR4 is approx. 4.4, Rogers RO4350B is 3.48). Higher constants reduce the size of the antenna but decrease bandwidth and efficiency. [ y_0 (corrected) = y_0 + \fracW_f4 \cdot

To design an inset feed, calculators require these primary inputs: Operating Frequency (

Enter your target operating frequency (e.g., 2.4 GHz for Wi-Fi). Run the Calculator: Get your Determine Gap Width (

): Dictates the resonance frequency (roughly half a wavelength). 2. Input Impedance ( Rincap R sub i n end-sub It transforms a tedious iterative process into a

: [ \varepsilon_reff = \frac\varepsilon_r + 12 + \frac\varepsilon_r - 12 \left[ 1 + 12 \frachW \right]^-1/2 ]

Where $G_1$ is the conductance of the radiating slot. Without a calculator, solving these equations manually leaves significant room for error.

$$ R_edge \approx \frac12G_1 $$