Microstrip Patch Antenna Calculator

A microstrip patch antenna is a flat, printed antenna used in wireless devices like Wi-Fi routers, GPS units, and mobile phones — and designing one requires precise physical dimensions matched to your target frequency and circuit board material. Enter your frequency (with unit), dielectric constant (εr), and substrate height into the Microstrip Patch Antenna Calculator to get the required Patch Width (W). Secondary outputs include Patch Length (L), effective dielectric constant (εreff), and the antenna's resonant frequency.

GHz

Relative permittivity of substrate material

mm

Results

Patch Width (W)

--

Patch Length (L)

--

Effective Dielectric Constant (εreff)

--

Resonant Frequency

--

More Electrical & Electronics Tools

Frequently Asked Questions

What is a microstrip patch antenna?

A microstrip patch antenna is a type of radio antenna with a low profile that can be mounted on a flat surface. It consists of a flat rectangular sheet or patch of metal, mounted over a larger sheet of metal called a ground plane.

How does dielectric constant affect patch antenna dimensions?

Higher dielectric constants result in smaller antenna dimensions. As the dielectric constant increases, the effective wavelength decreases, allowing for more compact antenna designs.

What is the typical substrate height for microstrip antennas?

Common substrate heights range from 0.8mm to 3.2mm for most applications. Thinner substrates provide better efficiency but narrower bandwidth, while thicker substrates offer wider bandwidth but may have spurious radiation.

Why is the patch width larger than the length?

The width is calculated to optimize the radiation resistance and is typically larger than the length. The length is then adjusted based on fringing effects and the effective dielectric constant to achieve resonance at the desired frequency.

What materials are commonly used for microstrip antenna substrates?

Common substrate materials include FR-4 (εr ≈ 4.4), Rogers RT/duroid (εr ≈ 2.2-10.2), and ceramic materials. The choice depends on frequency, loss requirements, and cost considerations.

How accurate are these calculated dimensions?

The calculations provide good initial dimensions for design. However, factors like finite ground plane size, substrate losses, and manufacturing tolerances may require fine-tuning through simulation or measurement.

What frequency range is suitable for microstrip patch antennas?

Microstrip patch antennas are commonly used from UHF to millimeter-wave frequencies (300 MHz to 300 GHz). They are particularly popular in mobile communications, WiFi, GPS, and radar applications.