Hello everyone,
I'm having trouble simulating a Vivaldi antenna. My S11 is stuck near 0 dB when I use a coaxial feed, but the simulation works when I use a simple discrete port.
My Setup:
- The main antenna body is Aluminum.
- I have an FR-4 substrate on top with a Copper microstrip line for the feed.
- I am using a waveguide port to model the coaxial connector.
The most interesting behavior is that if I simplify the model to only the bare aluminum radiator and excite it with a discrete port directly across the slot, I get a reasonable S11 response. The problem appears exclusively when I introduce the FR-4 substrate, the copper microstrip line, and the coaxial waveguide port.
Could you provide guidance on the best practices for setting up the waveguide port for this specific geometry?
Any help or examples you could provide would be greatly appreciated. Thank you!
Reference of vivaldi antenna: RFSPACE UWB-3
