Learning Forum

[Rui Coito]

Hello everyone,

Recently I have been trying to understand how to simulate and quantify the coupling of a free space beam onto a planar antenna on top of a sillicon substrate. The geometry that I am using is the one presented in the image below.

The antenna consists of a double dipole antenna designed to work on the 220 GHz to 330 GHz range, connected to a quarter wave resonator based (resonance frequency = 275 GHz) on a coplanar stripline transmission line design. This structure is placed on top of a 700 micrometer thick Si substrate as shown in the image below,  

My questions are regarding how to setup the simulation such that i can have an idea if a free space beam can couple to the antenna, this beam is in later stages to be considered a gaussian beam but for simplicity sake can now be considered a plane wave. My idea was to have two ports, at the top and at the bottom of the geometry, as shown in the image bellow, 

where I could excite P1 using a plane wave excitation and by analysing S11 and S21 plots i would be able to understand if part of the signal coupled to the antenna+resonator if there was a ressonance peak on S11 or S21 plots around the frequency that the resonator was design for. However I am struggling to realize how to do this in HFSS because a plane wave excitation cannot be considered a port and I also think that a wave port is not the correct implementation here...

If more information is required I will be more than happy to provide it to you!

Thanks in advance!  

[Takeshi Itadani]

If you wish to place ports on the p1 and p2 faces and check the S-parameters, you need to set up Floquet ports.
Additionally, Floquet ports must be used in conjunction with periodic boundary conditions.
The following content may be helpful.

https://innovation.ansys.com/base/learning/courses/ansys-hfss-floquet-port/lessons/intro-to-ansys-hfss-floquet-port-lesson-1