HFSS Transient analysis of Vivaldi antenna

Hi,

I am trying to do transient analysis of two antipodal vivaldi antennas placed side-by-side using HFSS, to see the ability of the antenna to transmit and receive signals without distortion. I am following the procedure in the HFSS example guide of a Ridged Horn Antenna (attached herewith).

For this I have assigned perfect E boundaries to the top and bottom layers of the antipodal vivaldi. I have excited the antennas with waveports having height= substrate thickness and length= trace width of the vivaldi.

I have assigned one volt as the source magnitude for the first antenna's port and zero volt for the second, from the HFSS> fields > edit sources option, so that the first antenna works as the transmitter and the second works as the receiver.

However, I am getting the following error while attempting to run simulation: "Port refinement, process hf3d error: Too few conductors were found on port p1. There should be one conductor for each terminal, with one additional reference conductor. Unintentional contact between conductors may cause this error."

I increased the waveport size to length= 20Xtracewidth and width= 20Xsubstrate height, but still then it cannot solve. Now it says: "Port refinement, process hf3d error: Port 'p1' contacts more than one non-conducting material which violates the TEM terminal modes restriction.."

Can you suggest a way out from this. Is the process that I am following correct?

Thanks in advance.

Welcome fparveen,

It's probably easiest to use wave ports in a driven modal setup. Then you won't have this error.

Good Luck!

Hi,

Thanks for replying. Since, I am trying to do transient simulation, I had to select the 'driven transient' solution type. I followed the procedure described in the HFSS guide attached with my post, however, that is for a horn antenna. Here I am trying to do it with a system having two vivaldi antennas (TX and RX). My goal is to excite the TX antenna with a gaussian pulse associated for 1-4GHz and plot both the transmitted pulse (by Tx) and received pulse (by Rx).

Is there anything wrong with my port type or port size? Or is there any other issue that I am unaware off which is causing the simulation to fail? I am not understanding how my ports should be assigned for this purpose.

Thanks.

How many terminals do you assign on each port? There should be one reference and one additional conductor intersecting each port.

Thanks PlanarMetamaterials for indicating the word 'intersecting'.

Yes, I had two terminals for each port. However, previously my port height was exactly the same as the substrate thickness. So, both the top conductor (perfect E) and the ground plane (perfect E) were just touching the edges of the port. Now, I have extended the port slightly beyond the substrate height, and this solved the error. So I could simulate now.


However, after the simulation I found that, both of the ports are getting excited with the gaussian pulse. But, I want to excite only port1, whereas port2 being the receiver. Can you tell how I can assign this gaussian pulse only to port1?

Thanks again.

Glad that helped. You can change the excitations under the menu HFSS->Fields->Edit Sources.

Good Luck!