Hi,

I am designing stacked patch antenna in CST Studio Suite using Multilayer Solver. At first I was performing simulation with microstrip line feeding, however now I would like to design an antenna with coaxial probe feeding. My antenna structure is as follows (starting from the top)

1. Parasitic patch placed on the top substrate

2. TOP substrate (defined in

3. Driven patch placed on the bottom susbtrate

4. BOTTOM substrate

5. Ground (copper)

Because I was asked to work with infinite ground and substrates (only in length and width dimensions, the height I am defining on my own), I decided to use Multiple Layer option in Background properties and define my layer stackup as in the attachment.

In order to design coaxial cable, I decided to create three cylindrical structures:

1. Inner cylinder – this is the conducting wire. Material is PEC and it is going from below ground layer, through ground layer (but I cannot create any cut in the ground layer, because it is not possible when such layer is defined in Multiple Layer option of Background Properties (?)) and Bottom substrate up to the driven patch

2. Mid cylinder – this is the insulator that is of PTFE material.

3. Outer cylinder – this is coating that is of PEC material.

For such structure I define waveguide port by picking the face of mid cylinder and creating waveguide port. Unfortunately, when I perform the simulation, I encounter problem I cannot solve. The error states that:

The setup of port 1 is not supported. Please use multipin definition. Please don't use infinite ground for planar port definitions.

I was trying to solve this problem for a long time, but didn’t succeed. Does somebody know how to solve this problem? I would be really grateful for help.

Best regards,

Konrad