Antenna Design Calculators
11 free calculators with formulas and worked examples.
Dipole, patch, Yagi, horn, parabolic dish, and loop antenna calculators for gain, beamwidth, EIRP, and resonant frequency from VHF to microwave bands.
Dipole Antenna
Calculate dipole antenna length for any frequency — enter MHz, get half-wave and quarter-wave dimensions in mm. Includes gain (2.15 dBi), radiation resistance (73 Ω), and 50 Ω VSWR. Supports velocity factor for insulated wire.
Patch Antenna
Calculate rectangular microstrip patch antenna dimensions (width, length) using the Transmission Line Model. Outputs effective dielectric constant, edge-feed impedance, and nominal gain for common substrates like FR4 and Rogers.
EIRP / ERP
Calculate EIRP and ERP from transmit power, cable loss, and antenna gain. Check FCC Part 15 and ETSI regulatory compliance margins. Free, instant results.
Beamwidth
Calculate antenna 3 dB beamwidth, gain from aperture, and effective area. Determine HPBW for dish, horn, and aperture antennas. Free, instant results.
Yagi-Uda Antenna
Calculate Yagi-Uda antenna element lengths, gain, spacing, and impedance. Design directional Yagi antennas for any frequency. Free, instant results.
Horn Antenna
Calculate pyramidal horn antenna gain, E/H-plane beamwidths, and effective aperture area. Design horn antennas for microwave systems. Free, instant results.
Parabolic Dish
Calculate parabolic dish gain, HPBW and effective aperture. Design satellite and microwave dish antennas. Free, instant results.
Loop Antenna
Calculate loop antenna radiation resistance, Q factor, bandwidth, and gain. Design magnetic loop antennas for HF and VHF bands. Free, instant results.
Helical Antenna
Design an axial-mode helical antenna: enter frequency, turns, helix diameter, turn spacing and wire size to get directivity, half-power and first-null beamwidths, axial ratio, input resistance and pitch angle by Kraus's formulas, with warnings outside their valid range.
Monopole / Whip Antenna
Input impedance, radiation resistance and directivity of a monopole or whip over a ground plane at any height, from the induced-EMF model by image theory, plus the quarter-wave length and the base-loading inductance a short whip needs.
Antenna Downtilt
Find the downtilt that puts a sector antenna's upper half-power edge on the cell edge, the ground footprint of the half-power beam, and the gain toward the cell edge from the 3GPP vertical pattern, with Earth curvature included.
About Antenna Design Calculators
Antennas are transducers between guided electromagnetic waves (in transmission lines) and unguided waves (in free space). Their performance is characterized by gain, beamwidth, impedance, bandwidth, and polarization — all determined by physical geometry and the surrounding environment.
Dipole antennas are the reference: a half-wave dipole has 2.15 dBi gain, omnidirectional azimuth pattern, and ~73 Ω feed impedance. Shortening the dipole increases impedance (adding a series capacitance) and reduces efficiency; loading coils or capacity hats restore resonance without full physical length. Yagi-Uda arrays stack a driven dipole with parasitic directors and a reflector to achieve 7-15 dBi gain with a narrow beam — standard for VHF/UHF amateur radio, satellite downlink, and point-to-point links.
Patch antennas are planar resonant structures built on dielectric substrates, popular in WiFi, GPS, and mobile devices where low profile and PCB integration matter. Gain is typically 5-8 dBi with broad beamwidth. Horn antennas are the RF equivalent of optical lenses — they flare a waveguide mouth to reduce diffraction and achieve 10-25 dBi gain with clean aperture efficiency, widely used as feed elements for parabolic dishes.
EIRP (effective isotropic radiated power) combines transmit power and antenna gain into a single figure of merit that determines received power at any range via the Friis equation. Regulatory limits (FCC Part 15, ETSI EN 300 328) specify maximum EIRP — not transmit power alone — making this calculator essential for compliance work.
Advanced Simulation Tools
Wire Antenna Simulator (NEC-2)
Solve your own wire antenna with the NEC-2 method of moments: dipoles, Yagis, verticals and loops, element by element. Radiation pattern, gain, impedance, VSWR, efficiency and current distribution, at one frequency or across a sweep, with a multi-objective optimiser on Pro.
Satellite & Terrestrial Link Budget
Compute probabilistic link margins using ITU-R propagation models (P.618 rain, P.676 gaseous, P.840 cloud) with climate data read from the ITU-R maps at your site. Enter EIRP, G/T, frequency, and site latitude and longitude. Get a full line-by-line budget, availability curve, and Monte Carlo confidence intervals over rain, pointing, and EIRP/G·T uncertainties.