I've designed a PCB in Eagle to host a GPS Receiver module and a GPS patch antenna. The RF input to the module is specified as a 50Ω unbalanced (coaxial) RF input. I used this calculator to calculate the required width and spacing for a co-planar wave-guide transmission line, and as you can see I got pretty close to 50Ω characteristic impedance using parameters from here. I ended up with a 32 mil trace width and 6 mil separation. Does that seem reasonable?
Here is a screen capture of what my board looks like:
Both the area fills (top and bottom) are GND, and I stitched vias approximately every 75 mil intervals between the top and bottom ground planes all around where the patch antenna is placed and along side the antenna feed to the GPS module. I didn't have any guidance on how to do this properly, so I just kind of eyeballed it. Perhaps it's overkill? I also stopped the top-side ground plane short of the chip to follow guidance that there should be no traces or solder mask under the GPS module.
The inner solid line square is 25mm and represents the actual patch antenna footprint. The dashed line around the patch antenna is a 27mm square that represents the required ground plane under the antenna, as I read it's datasheet. The feed length is about an inch (which is much less than the wavelength at 1575.42MHz) so I don't think path loss is of any concern here. I rounded the feed path it to "avoid sharp corners." I reckon that doesn't really matter too much, but I figured I may as well. Finally I used a 0.9mm drill size for the antenna pin, which I intend to solder on the back side. Does that all seem sound?
If I haven't given adequate background information in some regard, please let me know in a comment and I am happy to add information as necessary if I can. Just looking for an objective review as these are topics that I don't consider myself an expert in, and I can't think of a much better place than here to find knowledgeable and helpful colleagues.
I added a bunch of "random" vias within the ground stitching region under the patch antenna per @Dave's suggestion. Here's an updated board screenshot: