Antenna design,
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Free calculators and guides for patch antennas, microstrip lines, Smith chart matching, dipoles and RF exposure. Textbook equations, full-wave checks, and no sign-up.

Try a frequency

Frequency Board

Wavelength in air: 12.2 cm
Half-wave dipole: 5.84 cm
50 Ω microstrip width: 3.11 mm
Patch W × L: 37.6 × 29.1 mm

Closed-form estimates (Hammerstad, Balanis). Open any result for the full solver.

3D radiation pattern of an inset-fed patch antenna at 2.45 GHz, 2.48 dBi peak gain — From the patch antenna calculator: a 2.45 GHz inset-fed patch on FR-4.

To-scale layout of a 37.58 by 29.30 mm inset-fed patch on FR-4 with dimensions — From the patch antenna calculator: a 2.45 GHz inset-fed patch on FR-4.

Antenna design

Patch antenna calculator

Design a rectangular or circularly polarized microstrip patch from your laminate and frequency, then check it with a 3D full-wave solve before you order boards. Inset feed, quarter-wave transformer or coaxial probe.

Port solver. A 2D finite-element solve finds the 50 Ω feed width and εeff.
Patch synthesis. Width, length, inset depth or probe position, matched at f₀.
Analyze. S11, input impedance, Smith chart, gain, and 2D and 3D patterns.
Optimize. Set goals, sweep a dimension, or run Nelder–Mead.
Yield. Monte Carlo spread from etching, εr and thickness tolerances.

Open the patch antenna calculator

Polar radiation pattern of a patch antenna showing E-plane and H-plane cuts — E-plane and H-plane cuts, realized gain in dBi

Patch antenna return loss S11 plot with a -50 dB dip at 2.45 GHz — Return loss across the band

PCB and microwave

Microstrip width calculator

Find the trace width for any impedance on microstrip, stripline or grounded coplanar waveguide, as a single trace or a differential pair, with or without solder mask. A 2D finite-element solve of the real cross-section agrees with Hammerstad–Jensen to about 1%.

50 Ω on 1.6 mm FR-4: about 3.0–3.1 mm
Differential pairs: Zdiff, Zodd, Zeven
Line section: loss, S11, S21, .s2p export

Open the microstrip calculator

3D view of electric and magnetic field arrows along a microstrip line — Electric and magnetic fields along one guided wavelength

Finite-element potential field in a microstrip cross-section over FR-4 — FEM cross-section, 50 Ω line on FR-4

Match it, size it, keep it safe

Smith chart showing a matching network moving a load impedance to 50 ohms

Smith chart tool

Add series and shunt L, C, R, lines and stubs and watch the impedance move. Solve exact L, π and T matches, or import an .s1p file and sweep S11 and VSWR.