Link Budget & Patch (Microstrip) Antenna Calculator

Patch (Microstrip) Antenna — Design & Link Budget Calculator

All calculations are approximate and educational. Values are in SI units unless specified.

Operating Frequency (MHz)

Dielectric Constant εr

Substrate thickness h (mm)

Conductor thickness t (mm) — optional

Feed Offset from center (mm) — set 0 for center-fed

Target Input Impedance (Ohm)

Link Budget Inputs (Transmitter/Receiver)

Tx Power (dBm)

Tx Antenna Gain (dBi)

Rx Antenna Gain (dBi)

Cable / Connector Losses (dB)

Distance (meters)

Receiver Sensitivity (dBm)

Patch Antenna Design Results

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Link Budget Results

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Radiation Lobe (Polar)

Patch Visual (mm)

Notes & Formulas

Key formulas used (rectangular patch):

• W = c / (2 f) * sqrt(2 / (epsr + 1))
• eps_eff = (epsr + 1)/2 + (epsr -1)/2 * (1 + 12*h/W)^(-1/2)
• DeltaL/h = 0.412 * (eps_eff + 0.3)*(W/h + 0.264) / ((eps_eff - 0.258)*(W/h + 0.8))
• L = c/(2 f sqrt(eps_eff)) - 2*DeltaL
• FSPL (dB) = 20 log10(4 * pi * d * f / c) — f in Hz, d in meters
• EIRP (dBm) = TxPower + TxGain - TxLoss
• Prx (dBm) = EIRP + RxGain - FSPL - RxLoss