To effectively reflect an electromagnetic wave, it is not necessary to use solid metal reflectors. It is enough to use a grid of wires. In addition to saving metal, such a reflector has a much lower windage compared to a solid mirror. Part of the energy seeps through the grid. This calculator allows you to calculate the size of the cells and the loss of electromagnetic energy for leakage.
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Limitations and features of antenna calculation
The transmittance p shows the percentage of energy that has gone beyond the reflector. Given the allowable level of leakage loss p and the diameter of the grid wire d, we can find the minimum size of the reflector cell b. It is enough to maintain the distance b between the wires of the grid parallel to the electric field vector E. I.e. with vertical polarization—between vertical wires.
For a perforated reflector, a very small hole diameter corresponds to a very small mesh, and leakage loss can be less than the set allowable value. At the same time, a hole diameter greater than 0.4λ is unacceptable for correct calculation.
For the grid reflector the calculation is by the following formula (p in absolute terms, i.e. for 1% p=0.01):
H (2)0 (ikb), Н(2)0 (kr) – cylindrical Bessel functions of the 3rd kind (Hankel functions), k = 2π/λ – angular wavenumber for free space, λ – wavelength, r=d/2 – wire radius.
For the perforated reflector the calculation is by the following formula:
d – perforation hole diameter, b – perforation pitch, t – reflector sheet thickness, λ – wavelength.
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