Regarding PCB IFA microstrip antenna mirror image on ground plane hole areas
Thanks for asking an intriguing question. The short answer is &quot;no&quot;, you do not need to consider a mirror image of that inverted-F antenna when considering the adequacy of your ground plane.
The inverted-F antenna acts as a short monopole, and as such, you definitely need a ground plane. But without doing a full simulation, you can think of the RF currents induced in the ground plane as a simple set of radial spokes spreading out from the feed point. Your rows of four through-holes would be most troublesome if they were cutting across those radial lines, and least troublesome if they aligned with the radial lines. It could help a tiny bit to nudge them apart, so the ground plane isn't completely interrupted by the row of 4. If your PCB extends at least a quarter-wavelength in all directions, I'd consider it to be quite adequate.