Planar Inverted F Antenna Calculator

The Planar Inverted-F Antenna (PIFA) Calculator helps RF engineers, antenna designers, PCB engineers, IoT developers, wireless communication professionals, researchers, and students estimate the fundamental dimensions of a Planar Inverted-F Antenna for a selected operating frequency. By entering the operating frequency, the calculator determines the free-space wavelength, resonant current path length, patch length, patch width, recommended antenna height, and minimum ground plane size. PIFA antennas are widely used in smartphones, tablets, IoT devices, Bluetooth, Wi-Fi, LTE, 5G NR, GPS, RFID, wearable electronics, embedded wireless modules, automotive communication, and compact portable devices because of their low profile, good impedance matching, and multiband capability.

Enter Frequency exactly in the units shown by this planar inverted f antenna. Check the operating band, unit prefix, and decimal position before calculating; these are the inputs used by the formula.

• Frequency — use GHz.

The results describe the calculated planar inverted f antenna values for the inputs you entered. Check each value against the available space, selected components, feed system, and operating conditions before making a final design decision.

The Planar Inverted F Antenna uses λ = c/f Resonance Path ≈ λ/4 Patch Length ≈ λ/8 Patch Width ≈ λ/8 Height ≈ λ/20 Ground Plane ≈ λ/2 . Supply Frequency (GHz) in the displayed units, then use the calculated values as the first engineering target for this microstrip & printed antennas design or analysis.

This calculator is based on the fundamental operating principle of the Planar Inverted-F Antenna (PIFA), which is a quarter-wave resonant antenna derived from the Inverted-F antenna (IFA). The first step calculates the free-space wavelength using λ = c ÷ f, where c is the speed of light and f is the operating frequency. As frequency increases, the wavelength decreases, allowing the antenna to become physically smaller. The effective resonant current path is approximated as λ ÷ 4 because a PIFA behaves as a quarter-wave resonator with one end shorted to the ground plane. The shorting plate or pin effectively folds the resonant path, significantly reducing the antenna size compared with a half-wave radiator. The patch length and patch width are both estimated as λ ÷ 8, providing a practical starting point for compact rectangular PIFA designs. The antenna height is approximated as λ ÷ 20, representing the spacing between the radiating patch and the ground plane. Increasing this height generally improves impedance bandwidth and radiation efficiency but also increases the antenna profile. The recommended ground plane size is estimated as λ ÷ 2 because the ground plane forms an important part of the overall radiating structure and strongly influences resonance, radiation pattern, impedance, and bandwidth. These equations provide theoretical starting dimensions that are widely used during the initial design of printed PIFA antennas before electromagnetic optimisation and practical tuning.

Use the calculated dimensions as an initial design reference rather than final manufacturing values. During PCB implementation, the resonant frequency is strongly affected by substrate dielectric constant, PCB thickness, nearby batteries, displays, shielding cans, connectors, metallic enclosures, and other internal components. Leave the radiating patch slightly oversized and optimise its dimensions during prototype testing to achieve the desired operating frequency and bandwidth. Verify return loss (S11), VSWR, radiation efficiency, total radiated power (TRP), total isotropic sensitivity (TIS), impedance bandwidth, and radiation pattern using a vector network analyser (VNA), anechoic chamber, or OTA measurement system. Electromagnetic simulation using CST Studio Suite, Ansys HFSS, FEKO, Keysight ADS, or EMPro is highly recommended to optimise the feed location, shorting pin position, ground plane geometry, matching network, and multiband performance before production.