okay let's continue with our topic of
Cosimulation and show you how to use
this design method
with the Ansys HFSS MCAD (Mechanical CAD)
and the Ansys HFSS Circuit.
HFSS is the Electromagnetic simulation tool
and the HFSS circuit
is the circuit tool to match and tune the antenna element.
Again two different solve methods Electromagnetics
and Circuit. So, in our Series-3 video
on the 5G smartphone, we demonstrated
this technique - this method of design.
And, in these videos we used a PIFA structure
for the 5G New Radio frequency range
and a Patch Antenna Array for the 5G
Millimeter frequency range.
And, the design goal was to fit these structures
on the sidewall of the smartphone
as well as place them
in multiple locations on the phone.
So, in this module, we're going to use a
simpler model,
we're going to use a simple model geometry
to demonstrate this co-simulation
technique with the goal of bending or
folding the element for use on the
sidewall of the phone.
That bending will create a parasitic effect,
most probably a capacitive effect but, let's check it.
Okay, let's use this rectangular edge fed
patch antenna. It's on FR4, it is
synthesized for 3.5 GHz and we'll use a
geometry model already created for you
using the HFSS antenna toolkit.
So, let's go ahead and launch
the Ansys Electronic Desktop,
and go ahead and launch the Antenna Tool Kit.
Let's begin by creating a rectangular
edge fed patch antenna from the antenna
toolkit with the required design
parameters. Here's the HFSS created
geometry model as synthesized from the
toolkit. Go ahead and analyze this model
and once the analysis is done go and
view the results as generated from the
toolkit as well. Now the goal is to fold
or bend the antenna so that it fits on
to the sidewall of the smartphone.
Here is the folded antenna model design.
Go ahead and reanalyze, and once the
analysis is done go ahead and view these
results. Return loss, the Input Impedance
and the Total Radiated Power of the antenna.
Plotting both the planar and the
folded antenna results onto one plot,
you can see the changes that resulted
from this bending - from this folding.
Here's the comparison, now let's try and improve
this folded response by improving the
impedance match at the input and this
folded model design resonates closely to
3.4 GHz. So, let's use
this frequency to match using the Smith
tool inside of HFSS circuit.
In the project modeler window go ahead and
insert the HFSS circuit and once that
appears select the HFSS MCAD model
and bring it up to the HFSS circuit by
copy and pasting the design into the
circuit or just by selecting and
dragging the HFSS model into the HFSS circuit.
As seen in the project manager window,
the HFSS model is a sub-circuit
design within the HFSS circuit.
A hierarchy is set up.
Within the 3D modeler window use Ctrl+D
to maximize the view of the MCAD model as a
circuit schematic block in the circuit domain.
Let's go ahead and insert a port to the
model and select the microwave port
using the Edit Port option by right
mouse clicking on the inserted port.
Go ahead and flip the port vertically if
you want to view the ground on the
bottom of the schematic.
Create a voltage source for this port,
A sinusoidal voltage port since we are
using a microwave port implementation.
Be sure to edit the properties for this
port and use one volt as the AC mag and
the frequency set to 3.4 GHz.
Add a circuit solution setup of linear network
analysis, use the same frequency as the
HFSS model, so we're sweeping between
1.75 GHz and 5.25 GHz and we can use
0.5 GHz steps.
Go ahead and analyze, and when the analysis
completes, go ahead and view the results
which should be the same as in the HFSS
MCAD model. Here we copy and pasted the
results for comparison on one plot.
Let's go ahead and use the Smith tool option
from the results tab for designing the
matching Network. Again, select 3.4 GHz
to view where it's located on the Smith chart.
We'll use this point to create
a conjugate match. Select the button named
the conjugate and select the 3.4 GHz location.
A circle appears and then indicates
the conjugate point for matching
on the Smith chart.
Select the matching tab now and select the
button - "New Match" to create some matching
network configuration and select the
center of the Smith chart. Now the number
of elements in the component scheme that
that's left up to you for your desired goal.
For our purpose is to show the
process. So, let's use a minimum number of
points to realize a match and for this
model it will use a series C
and then a shunt L. And, as you can
see by the values they're very small.
Go ahead and export this Network
and this appears as another sub circuit in the
project tree, another example
of hierarchy. Drag and connect this matching
network between the port and the HFSS model.
Go ahead and reanalyze. Again, view the
results and you can see, here's a change
in the return loss and the input
impedance with and without this matching
network. Now let's go ahead and push the
excitation from HFSS circuit with this
matching network back into the HFSS
MCAD model. We are creating this dynamic
link between circuit and HFSS EM
simulation solvers. Now the results for
the return loss and the radiation pattern
from the planar model, the folded model
with and without tuning are shown here,
together in one plot. You can see that
the folded antenna model with the matching
circuit created with the Smith tool in
the HFSS circuit improved the
return loss as well as increased gain in the
radiation pattern. Again a result of
Cosimulation using both HFSS
Electromagnetic simulation and HFSS circuit.
So, in this video module I showed you how
to create a Cosimulation project
inside of the Ansys Electronic Desktop,
using the HFSS Mechanical CAD (MCAD)
and the HFSS Circuit. We used the model
geometry created from the antenna
toolkit and we folded the antenna
90 degrees with the goal of fitting it to
the sidewall of the smartphone. And, this
folding did indeed add some capacitance
to the model geometry which was
originally flat, planar. We used a Smith
tool inside of the HFSS Circuit to
rematch the design to 3.5 GHz
and push the revised circuit
excitation back into HFSS MCAD to see
the improved return loss and
gain pattern. With the increased need to stay
connected, the need to impedance match
that antenna element or elements in an
array is greatly increased. As the better
the match of the antenna element,
the better the performance
of the entire unit.
Which for our smartphone means
better wireless connection.
The method of co-simulation is increasingly
of value for your antenna design needs.
check out our channel for more How-to videos
and visit ansys.com/courses today.
Thank you