In a ceramic patch antenna for GPS if we remove the double sided adhesive tape completely from the bottom we get a metal layer on bottom. What is the purpose of this metal layer ?
If we mount ceramic patch on a double sided PCB (top layer having ground plane for patch antenna and bottom layer having feed line) feed point goes through the PCB to the bottom layer and soldered there. Bottom of the ceramic patch is fixed to ground plane on the top of PCB through adhesive. So there is not contact of metal layer (which is there at the bottom of ceramic patch) to ground plane on PCB. So what is the purpose of that metal layer ?