patch antenna ground
Hi, vfurlan:
It really depends upon how your patch antenna looks. If it is low profile with regular substrates, the Zin will be very stable with the ground planes 3 substrate thickness bigger than the patch. Certainly, the pattern is affected much. For some high profile patch antennas such as aperture coupled antenna with a big air layer between the patch and the feed line, the size of the ground plane will have big impact, it is hard to give a general guide line on the size of the ground plane. It really depends upon reality. If your patch antnena involves slots as part of your design, you may pay serious attnetion to the ground plane size, the finite ground can be an integral part of your radiator. The size and shape are very critical.
Best regards,