When an antenna is printed on a PCB, the effective permittivity of the structure has to be taken into account when calculating the wavelength on the PCB material. This involves calculating the effective permittivity of the PCB material. The reason is that when an antenna is built on the PCB using two traces, the electric field in the reactive near field region spreads partially in air and partially in the PCB material. This modifies the effective permittivity. A recent calculator released by Signal Processing Group Inc., does this calculation. The calculator is written in Javascript and is available from the ” Free articles and software…” section of the SPG website. Interested readers can download the calculator for free from there.