This article describes the workflow and settings required to use Keysight Advanced Design System (ADS) design automation software on Nimbix cloud to completely design, characterize, and optimize a circuit without changing tools.
To access Keysight ADS on the Nimbix platform, the following steps are required:
1. Select Keysight ADS release from the Compute dashboard.
NOTE: If the option is not available in the first-page menu, press on “More” at the bottom of the page as shown in the image below:
2. A splash window will open. Select the Desktop option as shown below to start your project:
3. The Nimbix Cloud set-up screen opens and here you must choose some of your settings by clicking on the Tabs on the top of the window (General, Optional, etc.) one tab at a time.
UNDER GENERAL TAB
- Under “Machine type”, clicking on the caret on the right, you can select the type of machine you want to run your job on. The decision on machine type selection is based on the size and complexity of your model and the cost associated with the machine type (some machines will have higher RAM, others will only run the job on a single CPU, others will have better graphics and therefore higher cost, etc.).
NOTE: When running interactive based applications, you’ll find that selecting an NC9 or any NC* machine types should offer significant visual performance over not selecting an NC machine type. By selecting an NC machine, this places a GPU on your head-node and offers better visual performance. Another thing to keep in mind is that when running interactively you can use a web browser, or in some cases for large models or you might consider using RealVNC.
2. Select the number of cores:
The machine type you selected in the previous step, will dictate the increment in the number of cores that you can choose/select. For Keysight ADS applications it is recommended to leave the default cores (1 node) option for optimal performance (in this example would be 16 cores):
UNDER OPTIONAL TAB
- Assign a JOB LABEL (give a name that will help you keep track of your running jobs. For example, My_Low_Pass_Filter_design). This example will walk you through the steps recommended to tune a simple low pass filter:
2. Leave blank the wall time limit, Case file (for a new simulation), and the IP address. The Window size needs to be kept as default.
UNDER STORAGE TAB
Select vault type: The default vault is “Elastic_File”
The "Elastic_File" vault is recommended for small to medium size jobs, such as KEYSIGHT ADS projects, Icepak projects, simple linear Mechanical Analysis projects, some HFSS, and simple Fluent projects (not multi-phase). For any complex and computationally heavy jobs, and where partitioning the job over the number of cores becomes challenging, the “Performance_SSD” vault is strongly recommended. The “Performance_SSD” vault can be found in the drop-down under the "Select Vault" tab (NOTE: requires a subscription and extra monthly payment to have access to the “Performance_SSD” vault).
Before submitting your job for running, you can preview your settings under the Preview Submission tab.
Start your Keysight ADS job in Nimbix (design and simulation) by clicking on the Submit button as shown below (your preview image may differ):
After Keysight ADS has been successfully launched, you should be able to see the Keysight ADS preview and can access the window by clicking on it (you can see details on the number of nodes, some information regarding memory, etc.). Click on the preview window in your browser to open Keysight ADS in a new window/tab. You are now inside the KEYSIGHT ADS environment.
NOTE: If the preview window does not show in your browser, click on the “Click here to connect” link to start the Keysight ADS in a new browser window or tab.
Keysight ADS Setup and Solution On The Nimbix Cloud (abbreviated steps)
- Start by setting up the new design environment and workspace (for this example will use the option shown below since we will do design and simulation in the same environment):
NOTE: Use the “Show Details” button to display the particulars of each option
Click the “OK” button to start the program.
- The Keysight ADS software starts and the main window with the default workspace is ready to be used.
NOTE: A splash window is presented to the user with 2 options: “New to ADS” and “Familiar with ADS”. The first option is for novice users and presents the users with an abbreviated set-up wizard and a workflow Quick Start menu (shown). Dismiss the “Quick Start” by pressing the “Got it” button. For an advanced user, the second option may be more appropriate as it provides more control by the user without help options.
3. Click the “New Workspace” button to create a New Workspace and schematic window (optional for “New to ADS” option) or use the existing workspace and schematic. Enter the workspace name and folder of choice, then click the “Create Workspace” button:
4. Create a new Schematic in the current workspace (NOTE: This step is optional if the “New to ADS” option is used with the default workspace).
5. Enter the name for the new schematic as desired:
6. Create the low pass filter (use Lumped Component option) à drag and drop lumped components.
NOTE: In order to create the circuitry, select the required component (click on the component button – for example, a capacitor shown here) and drag the mouse over the schematic grid. Left-click to place the component (NOT A DRAG AND DROP MENU to SELECT AND CLICK):
Hit the “Esc” button to quit the current selection and select the component. Once selected, click the “Rotate” button to change the orientation of the component (vertical) if needed:
Insert all components, add “TermG” (port impedance termination from the “Simulation-S Parameters” list), grounding, and connect them using the “Insert Wire” button.
7. Insert S-Parameter simulation add-in (click the “SP” button in the left toolbar and drag the mouse over the schematic canvas). Left lick to add the S-Parameters simulation module (gear on the left links to simulation module):
NOTE: Default values are kept in this example. Please use the values of your individual design as required. Changing the default values can be done by either clicking on the value and changing it or by the right-mouse button.
8. Simulate: Click the gear button (Simulate) in the top toolbar to start simulation (NOTE: Choose the simulation step, frequency domain, and parameters of your LP filter as desired).
NOTE: The user can change the properties of the components by right-mouse clicking and choosing Component to Edit Component Parameters or clicking on the value in the window and changing it as desired. The same applies to the S-Parameters simulation frequency range and step.
9. View results (A separate output window opens with the same name as the cell name) once simulation completed
a. Insert the S11 parameter in a Smith chart to visualize the return loss.
b. Insert filter performance (S21) in a rectangular chart to let ADS do the real and imaginary computation for you and display it in dB.
10. Inspect your results for accuracy and completeness in the Smith and rectangular chart.
NOTE: The performance of the LC filter seems to be working as expected (higher frequencies, above 7 GHz, are attenuated).
How To Perform Tuning Using Keysight ADS In Nimbix
1. Select “Tuning” by clicking the “Tuning” button in the top toolbar.
2. Click on the component you want to select (you can select more than one component to tune) and a slider will be added to your window after clicking the “OK” button:
3. Move the sliders to fine-tune your low pass filter and see the S parameter in the rectangular graph (performance) change.
NOTE: By changing the values of the components (capacitance and inductance) the user can change the performance of the low pass filter without the burden of prototyping and building physical samples. This allows the user to evaluate the performance of her/his design in a quick and cost-effective way. After tunning your filter you can save the tuned parameters after closing the “Tune Parameters” window” into the schematic.
4. Save the schematic and the workspace and close (Exit Advanced Design System) to finish your work session.
NOTE: Confirm Keysight ADS exits by choosing to click the “Yes” button in the confirmation window.
NOTE: Return to your account and confirm that the NIMBIX session from the dashboard has finished ensuring that you properly shut down the application.