Helical Antenna Design Calculator

Helical Antenna

Helical antennas are one of the easiest to design in antenna. The conductor width isn’t of great importance in the design. The greater the number of turns the greater the directivity or antenna gain. But make sure to keep the winding on both receiving and transmitting antennas in the same direction, since the wave is polarized.

This online calculator helps you calculate Antenna Gain, Impedance, Diameter, Space between coils, Length of wire, Half Power Beam Width, Beam Width First Nulls, and Aperture.

Select M or MHz
Number of Turns
Space between coils


\[Antenna Gain (G)= 10.8 + 10*log10 \left(\left(\frac{C}{\lambda}\right)^2 * N * \left(\frac{S}{\lambda}\right)\right)\]
\[Characteristic Impedance (Z) = \frac{150}{\sqrt{\frac{C}{\lambda}}} \]
\[Diameter (D) = \frac {\lambda}{\pi}\]
\[SpacingBetweenCoils (S) = \frac {C}{4}\]
\[LengthOfWire (L) =N * \sqrt{\lambda^2 + S ^2}\]
\[HPBW = \frac{52}{\left( \left( \frac{C}{\lambda}\right) * \sqrt{N * \left( \frac{S}{\lambda}\right)} \right)}\]
\[BPFN = \frac{115}{\left( \left( \frac{C}{\lambda}\right) * \sqrt{N * \left( \frac{S}{\lambda}\right)} \right)}\]
\[EffectiveAperature(Ae) = \frac{D * \lambda^2}{4 * \pi} \]

where :

  • G = Antenna Gain
  • Z = Characteristic Impedance
  • D = Diameter
  • S = Spacing between coils
  • L = Length of wire
  • HPBW = Half power beam width
  • BWFN = Beam width first nulls
  • Ae = effective Aperture
  • C = Circumference of a turn on the helix antenna 

Any questions? Drop them here!