Kharchenko (BiQuad) antenna calculator

About

This calculator works out the dimensions of a Kharchenko antenna — the zigzag BiQuad. It is a directional antenna with useful gain, built from two square loops in front of a metal reflector, and it is widely used for Wi-Fi, GSM, LTE and similar work.

W — width of the loops, H — height, R — side of the rhombus, A × B — size of the reflector

Standard frequencies
Operating frequency		MHz
Feedpoint impedance
Units

Notes:

Standard frequencies: pick one from the list, or type your own.
Input impedance: the usual 50 Ω and 75 Ω are supported.
Units: results can be shown in millimetres, centimetres or metres.
Frequency range: the calculator is tuned for 400–3000 MHz.
Reflector: make it from sheet metal or fine metal mesh.
Loop material: copper wire of a suitable diameter (see the AWG size).
Build accuracy: hold the calculated dimensions to ±1 mm if you want the performance the numbers promise.
Feed: the coax connects at the centre of the lower loop, keeping the calculated gap.
Polarisation: linear, in the plane of the loops.
Gain: typically 10–12 dBi, depending on frequency and how well it is built.
Beamwidth: roughly 60–70 degrees.
Assembly: the reflector must sit exactly the calculated distance behind the plane of the loops.

How to cite this calculator

UR3PKI. «Kharchenko (BiQuad) antenna calculator». CyberDev.Space. https://cyberdev.space/en/radio/calculators/antennas/kharchenko (licence CC BY-NC-SA 4.0).

The licence lets you use this material freely, including in teaching materials, but only with attribution to the author and a link to the source.