# Manufacturers' recommendations for ground plane for GPS patch antennas

I see requirements for specific ground plane sizes in many GPS antenna datasheets, but I also see many devices that ship with significantly smaller ground planes. Do these integrators know something that the GPS vendor doesn't, or am I missing something about the requirements?

As an example, u-blox SAM-M8Q Hardware Integration Manual specifies a 50mm x 50mm gp, but all off-the-shelf PCBs I see on the Web look much smaller (for scale, the M8Q patch is 15mm x 15mm).

SAM‑M8Q GNSS patch antenna module is intended to be placed in the middle of 50 x 50 mm GND size board, but a larger or smaller ground plane can be used. When using smaller than 40 x 40 mm ground plane, the performance may get decreased significantly.

• The smaller ground plane will probably result in a less sensitive GPS. If I recall correctly, there is a table in the integration manual with expected sensitivity performance with different size ground plane. – Peter Karlsen Nov 2 '18 at 18:48