I am using a pcbStack object to model a custom patch antenna with the three layers consisting of the top patch, dielectric and ground plane. I want to understand what is going on with the modeling of the feed in two scenarios (especially with the red sphere that is supposed to represent the feed). When I specify the FeedLocations property to be [x y 1], I understand that it means that the antenna is directly fed at the surface. However, why is in the form of a red sphere? Is it possible to specify a 2D feed? What does the region of the red sphere represent? (as shown in figure)
When I specify the FeedLocations property to be [x y 1 3], I understand that it means that, by specifying the ground plane as 3, a coaxial feed is created. However, again, there is this curious red sphere that appears at the bottom.
Moreover, if the FeedDiameter is set large enough, then the sphere appears to touch over the top surface as well. Does this mean that the top surface is also fed? So if I want a large feed diameter, how do I do that? (without letting it touch the top)
What does the FeedDiameter property actually refer to? The radius of the sphere?
My question is more or less about how the antenna toolbox models feeds (in any scenario, pcbStack or otherwise). I was not able to find any resource detailing on this.
Another question : How do you set the outer diameter of the coaxial feed? Is it automatically set for an impedance of 50ohm?
