How to design coaxial feed patch antenna?
I've been using the HFSS software currently for implantable antennas. I also have used the CST studio suite but for microstrip patch antenna. I'm trying to design a coaxial feed patch antenna. The work I'm trying to reproduce didn't mention the dielectric material for the coaxial feed. Also in HFSS how do you guys prefer to design the coax feed? I've seen YouTube videos where they cut the ground with the same radius for the outer conductor ( a cylinder of PEC) , then take a dielectric cylinder, and then another cylinder for PEC. Three of them have a length starting from the ground plane then extend to the bottom. Then they take a second inner cylinder of PEC with the same radius as the previous inner conductor that they take from the ground to the patch. Then at the bottom where the coaxial feed ends, they take a circle of outer layer radius and then assign a lumped port. But when i try to do that the results are deviating a lot. The return loss doesn't even go near -2dB. Do i need to create some vaccum material cylinders and then place the required material cylinders in HFSS? I'd be really grateful if you share your steps or resources that you follow to design them.