Where To Find This Example
Select Help > Open Examples... from the menus and type either the example name listed above or one of the keywords below.
Or in Version 14 or higher you can open the project directly from this page using this button. Make sure to select the Help > Enable Guided Help from the menus before clicking this button.
Design Notes
Optimization
Optimization adjusts element parameter values or equation values that are setup for optimization in order to meet defined measurement goals. Minimizing an error function describing the difference between the goal and the measured value is the objective of the optimization process. Multiple optimization methods are available, choosing which optimization method to use is dependent on the problem trying to be solved. Some optimization method are more efficient than others for a particular measurement being optimized. Details of the error function and the various optimization methods can be found in the AWR Design Environment Simulation and Analysis Guide.
Set Optimization Variables
Element parameters and equations need to be specified for optimization. Under the properties for an element or for an equation, the Optimize field must be enabled. The variable limits can be specified by enabling the Constrain field and entering values for Lower bound, Upper bound and Step Size. Using the Variable Browser (selected from Main Menu > View) aids in editing multiple optimization variables.
Set Optimization Goals
Next step is to specify the optimization goals. Goals are added from the project browser > Optimization Goals > Add Optimizer Goal... Goals correspond to measurements in a graph. Optimization can be performed on an output equation as long as the output equation is plotted on a graph. X and Y ranges, goal weighting and L-factor (error function is raised to the power of L-factor value) are all settings for the optimization goals.
Configure Optimization
Open the Optimization dialog box from Main Menu > Simulate > Optimize. Before starting the optimization, various configuration values can be set from the Optimization dialog box. There are optimization method specific properties as well as general settings. Click the Help for more information.
The optimization is initiated by clicking Start button.
Selection of Optimization Method
Which Optimization method to choose varies widely on the type of problem being solved as well as how the goals are configured. The AWR Design Environment Simulation and Analysis Guide gives a description of each Optimization method with information on what general class of problem that the particular Optimization method is best suited.
Logging Results to File
Optimization results including total cost, cost for each goal and optimization variable settings for each optimization iteration can be recorded in a JSON formatted text file when the Log to file option is enabled in the optimization dialog box. After the optimization is complete, the log file can be located from Main Menu > Help > Show Files/Directories > Logs. The optimization log files have the extension .json which can be viewed using a standard text editor.
Running Circuit Schematic Optimizations in Parallel
For Circuit Schematics, optimization iterations can be run in parallel on either the users computer or a remote simulation server. Additional licensing is required to run parallel optimizations. Refer to the Remote and Parallel Simulation section in the AWR Design Environment Simulation and Analysis Guide for details on configuring the AWR Design Environment to run parallel optimizations.
Project examples
There are three examples circuits and VSS systems in this project. For best optimization results, disable the Optimzer Goals that are not associated with the schematic or system diagram of interest. The project script Main Menu > Scripts > Project Scripts > Enable_Disable_Optimization_Goals (Main) can be used for enabling specific goals.
Distributed_LPF Example
This is an example of a microstrip lowpass filter with stopband zeros. Passband and stopband s21, passband s11 and passband group delay all have associated optimization goals. The group delay originates from output equations in order to demonstrated how output equations can be used with optimization. To set intial values, use the script Main Menu > Scripts > Project Scripts > Distributed_LPF_Initial_Values (Main)
Nonlinear Amplifier
This is an example of a nonlinear FET transistor with input and output tuners for match. The optimization variables are the magnitudes and phases of the tuners as well as the drain voltage of the transistor. Output equations are used to compute 2nd and 3rd harmonics in dBc. Optimization goals are total power, harmonics, nonlinear noise figure and DC power. To set intial values, use the script Main Menu > Scripts > Project Scripts > Nonlinear_Amp_Initial_Values (Main)
ACPR System
This is an example of a VSS optimization. This sytem makes a power and ACPR measurement on a QAM modulated amplifier. The amplifier design is nonlinear device in the circuit schematic "VSS Cosimulation Amplifier". Optimization goals are set for ACPR and Power. To set intial values, use the script Main Menu > Scripts > Project Scripts > ACPR_System_Initial_Values (Main)