Now I notice you sell a round steel 4-inch (10 cm) ground plane for GPS antenna purposes. (link denied because I am a new poster- despite being a customer since your very early days- because you apparently deleted my old accounts from non-use)
Apart from the difference in size, do you know what material the u-blox specs were measured on? Was it steel, aluminum, copper, silver? Bare or coated somehow? I imagine the surface details can make a difference to a high precision antenna, given the conductivity, internal loss tangent, and hence the vector RF reflectivity of steel is not the same as more conductive metals.
I think AMO used a plated PCB, so copper, with via punch-thrus
uBlox ships the units in the EVK’s with thin steel discs, something electrically conductive, but not attached to a ground. Basically a proxy for a car roof.
Thanks for that note! A copper PCB makes sense to me for an antenna ground plane. I wonder if the soldermask or other surface coating affects the pattern. But you can’t leave bare copper and expect it to stay un-oxidized. So u-blox went to the trouble of measuring and publishing detailed pattern and gain specs on their antenna, but I’m still not sure how if or how those numbers may be translated to a real-world application.
I think they just used a solder mask finish, but the copper isn’t magnetic, so you’d also need to consider attachment.
Perhaps you can “Create a Support Case” directly with uBlox, and ask for the ANTEX file and any material about the mounting and orientation used to come up with the phase-centers at different frequencies. They might also have some white papers on the size, shape and placements. Generally you want it centered, and large as practically possible for size/weight of the application.
One thing that’s consequential to the efficacy is the RF transparency of the plastic/coverings on antennas, and proximity of human body.
Places like Taoglas can do design and tuning studies.
What you place around it and the proximity of other active circuitry also impact things. So realistically you need to test your implementation “as built”.