I have designed a patch antenna array of 3 elements. Patch1 has a port (1), patch2 has port (2), and patch3 has port(3).
My questions are:
1- Is there a phase difference between port (1), (2) and (3)?
2- What is the difference if i feed all the patches to port (1).?
To the first question, this is something you should know ;-)
To the second question, not sure what you mean here. Do you want to feed all patches only on one port?
Some pictures or more detailed explanation would be helpful.
1. If the array is broadside, all the patches will be driven in phase. 2. If the feeds are combined and you want broadside radiation then the ports would still need to be in phase. There are numerous antenna textbooks that discuss how arrays work.