ECE 375 Lab 2: Design and simulation of a Stripline and Coaxial cable using CST Please see at the end of this handout for items needed to be included in your lab report.
Stripline: A stripline is a type of transmission line based on planar microwave circuitry. It
typically consists of a conducting strip surrounded by dielectric material and sandwiched
between two conducting ground planes. Because of the insulation provided by the dielectric
casing, the stripline can be easily miniaturized and provides enhanced noise immunity in
microwave circuits.
Basic schematics are shown in figure 1.
Figure1. Stripline
Introduction: Launch CST. Click New Template (Top left). A new window will appear; select MW & RF &
OPTICAL, then Circuit and Components and click Next. Select Planar Coupler and
Dividers and click Next. Select Time Domain as a solver and click Next. Then you can select
the units; choose mm for Dimensions, GHz for Frequency, ns for Time, Kelvin for
Temperature and click Next. Then set the Frequency range to be from 5 to 15 GHz, Monitor
the E and H field and define at 10 GHz. Hit Next and Finish. An untitled session will open (as
shown in the following picture). To create the models you need to use Modeling from the top toolbar (1). In order to make the simulations and the evaluations (Electric field, Magnetic field etc.) you should use Simulation. From the Parameter list (2) window (bottom) you can define the variables that you might need
to use. From Navigation tree (3) window (on the left) you can view/change all the created
models and specifically from 1D and 2D/3D Results you can see the values of the calculated
quantities. All objects can be seen at the main window (4), while on the right you can always see
the coordinate system (x,y,z).
At the bottom-right toolbar (5) you can select how the pointer will be used: zoom in/out with
the zoom mode, or the dynamic zoom mode (using scroll up/down will also do the same
anytime), drag the grid with the pan mode, rotate it with rotate mode/rotate in plane mode
(very useful) and reset to default.
Basic steps:
All of the parameters related to stripline are shown in the table.
1. Create a brick for substrate (Dimension are given below) and chose the material as ‘ new
material’ and fill the windows like below
2. For creating the stripline select face center (go to Pick> pick face center) of the substrate
and align the local WCS with the selected point (go to ‘Modeling>Align WCS>Align
WCS with selected point). They look like below
3. Now start to create stripline by creating a ‘brick’ and fill the window like below
4. To create the ground plane ‘Pick’ the face first (left figure) and then go to ‘extrude’ and
fill the window like right figure
The ground plane will be created and will look like below
Follow the same step 4 to create second ground plane.
5. Now it is required to create a “waveguide port” for providing power to your created
structure. Select the end face of the stripline (use zoom in option) from ‘Pick’ option.
Then go to Home>Macros>Solver>Ports>Calculate port extension coefficient, you will
see the following window
Click on ‘calculate and ‘construct port from picked face’. The port will be created like
below
Follow the same procedure to create the port on other side.
6. Go to ‘simulation’ and click on “Boundaries” and fill the window like below
7. For mesh setting, go to Simulation>Global properties>Hexahedral and fill the window
like below
8. Then go to ‘Set up solver’ and click on “start”. Your simulation will be started.
9. After running your simulation, from navigation tree click “2D-3D results” and observe
the field propagation through the designed structure (Watch the video for details).
10. For getting the power reflection/transmission, go to ‘1D result’ from Navigation tree and
select ‘S parameter’ and ‘S11 and S21’.
11. To observe the E and H field at port side, go to ‘2D/3D results’ from navigation tree like
below
12. To complete visualization of E and H field at 10 GHz, click on ‘E filed/ H field’ from
‘2D/3D results’ and use ‘smart scaling’ and ‘animate fields’ as ‘contour’. It will show in
a nice way like below static image
End of stripline.
****************************************************************************
Coaxial cable: Coaxial cable is a type of electrical cable consisting of an inner conductor
surrounded by a concentric conducting shield, with the two separated by a dielectric (insulating
material); coaxial cables also have a protective plastic jacket. Coaxial cable is a type of
transmission line, used to carry high frequency electrical signals with low losses.
Introduction: Launch CST. Click New Template (Top left). A new window will appear; select MW & RF &
OPTICAL, then Circuit and Components and click Next. Select Coaxial (TEM) connector
and click Next. Select Time Domain as a solver and click Next. Then you can select the units;
choose mm for Dimensions, GHz for Frequency, ns for Time, Kelvin for Temperature and
click Next. Then set the Frequency range to be from 3 to 6 GHz, Monitor the E and H field
and define at 4.5 GHz. Hit ‘Next’ and ‘Finish’. An untitled session will open (as shown in the
following picture).
Basic steps:
All of the parameters related to coaxial cable are shown below
Length of the coaxial line considered here, L= 40mm (Though in video it is 60mm. During simulation it was changed to 40mm from 60mm. Please consider it 40mm for your work).
1. Create a cylinder for central core (Dimension are given below) and chose the material as
‘PEC and fill the windows like below and it will like below shape
2. For creating the dielectric insulator make another cylinder just as above and fill the
window like below. Material should be PTFE loss free (please select from material
library)
3.
4. For metallic shield select face of the cylinder (go to Pick> pick face) and go to ‘Extrude’
option under ‘Modeling’. Fill the window like below and the structure is at right.
5. For outer plastic jacket follow the step 4. Fill the window as below
6. Now it is required to create a “waveguide port” for providing power to your created
structure. Select the dielectric face (radius, r1) from the structure end using ‘Pick’ option.
Then go to Simulation>Waveguide port and a window will pop-up like below. Just click
‘OK’. No need to change any parameter in that window. First port will create.
7. Follow the same procedure (step 6) to create the port on other side.
8. For mesh setting, go to Simulation>Global properties>Hexahedral and fill the window
like below
9. Then go to ‘Set up solver’ and click on “start”. Your simulation will be started.
10. After running your simulation, from navigation tree click “2D-3D results” and observe
the field propagation through the designed structure (Watch the video for details).
11. For getting the power reflection/transmission, go to ‘1D result’ from Navigation tree and
select ‘S parameter’ and ‘S11 and S21’.
12. To observe the E and H field at port side, go to ‘2D/3D results’ from navigation tree like
below
13. To complete visualization of E and H field at 4.5 GHz, click on ‘E filed/ H field’ from
‘2D/3D results’ and use ‘smart scaling’ and ‘animate fields’ as ‘contour’. It will show in
a nice way like below static image
And after cutting plane
Assignment: Your lab report (for both stripline and coaxial line) should have the followings:
1. Goal/ Aim of this simulations. 10 points
2. Brief theory (Maximum 10 full lines) for both stripline and coaxial line. 20 points
3. Steps that you have followed (very briefly). 10 points
4. Proper static image/ images with brief explanation. 30 points
5. Explanation of the reflected/transmited power from curve. 20 points
6. Conclusion 10 points
The post ECE 375 Lab 2: Design and simulation of a Stripline and Coaxial cable using CST Please see at the end of this handout for items needed to be included in your lab report. appeared first on Versed Writers.
