ground plane dimension
this time i want to ask that what should be the ground plane with respect to patch. actually i m designing an antenna and i m working on gain as i m increasing the dimension of ground plane the gain is also increasing so now patch has become small and ground plane is very large.so plz tell me what should be the ground plane dimension
regards
sameer
hi
it related to frequency and patch structure effect of ground on gain increase not very much and should adapt between them
so first define u frequency and then u antenna structure
As a very rough rule of thumb the actuall as oposed to radiative ground plane should be between 1/4 and 2 wavelengths at the lowest frequency.
In most antennas you have a resonant radiating element over a resonant radiating "effective ground" element to stabalise the charecteristics of the antenna. Often this radiating ground elelment is aranged to be a 1/4 wave or multiple there of stub to act as a psudo open cct to reflect all the energy back into the actual radiating element. Usually this will be mounted atleast two wavelengths (ie 17db loss) above any other non axial earth.
So you need to decide do you want your ground to be an anti radiator or an open circuit stub.