I just had the opportunity to test this filter on an EMSCAN ERX+, which shows the electromagnetic energy on the board. This really nicely shows where the energy is going. We're looking at buying one (they are about CA$100,000) so we were able to get them to come by for a demo, as they are also a Calgary based company.
With the tracking gen set to -30dBm output at 931mhz, at 1.88mm resolution, with the gerber overlay:
Without Gerber overlay
The feedport is to the right. I was measuring -6.1dBm of loss on the network analyser across the filter at this frequency. The brightest red is -21.2dBm with the blue background at -36.5dBm.
For fun, here's Sonnet's simulation of the current on the board at 931mhz.
Here's the resolution that the EMSCAN EHX+ (much cheaper) offers:
The ERX+ is quite a beast. It can now do down to 60uM (0.06mm) scan resolution, but this takes a pretty long time!