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Power Amplifier

This page contains improvements to the AWR Design Environment for PA designers.

Rapid Adoption Kits

Save time with PA design flow overviews and example

See the Power Amplifier Design Flow Knowledgebase page for an in-depth look at this project and flow used in the design of this Doherty power amplifier.

V15

This page lists improvements to the AWR Design Environment for PA designers.

Perform Fast Linear and Nonlinear Stability Analysis Using Loop Gain Envelope Evaluation

The project opens to a data display page and simulates.

License Requirements: Linear or Nonlinear Simulation and Advanced Stability Analysis (STB_100)

  1. In the Stability K and B1 Graph, note the K and B1 potential for instability. This is an easy to understand but not sufficient stability analysis metric.
  2. In the Stability Loop Gain Margins Graph note the Gain Margins, some of which are negative, indicating instability.
  3. Move the Marker and watch as the Loop Gain Envelope Graph changes. It is easily seen that as the Gain Margin becomes negative, the magnitude of the loop gain envelope is greater than one at zero degrees. This is a better indication of stabilty because it takes into account all possible termination impedances.
  4. Open the optimizer by clicking Simulate > Optimize. There is an optimizer goal set up for 60 degrees of Phase Margin.
  5. Start the optimization. In a short time, the phase margin envelope is optimized above the desired value and the instability is no longer present across the simulated frequency band and all possible termination impances.
    • The Stability Envelope series of measurements provide a much faster and still robust stability anslysis of your circuit. Rather than simulate N^2 reflection coefficients at each frequency, only N evaluations are needed.
    • The Phase Margin Envelope and Gain Margin Envelope measurements provide an easy to understand and directly optimizable metric for stabilty performance.

Directly Read Impedance Values from Load Pull Contours on Rectangular Real/Imaginary Graphs

The project opens to a data display page and simulates.

License Requirements: Load Pull (LPL_100)

  1. Note the new Rectangular - Real/Imag graph type at the upper right side of the data display.
  2. Contours shown on the Smith Chart and the Rectangular - Real/Imag graphs are the same.
  3. This graph displays complex data, like load pull contours, on a Rectangular graph.
  4. The axis can be set to gamma, impedance, or admittance.

Simulate the Impact of Video Bandwidth or High-order Harmonic Impedance on PA Performance

The project opens to a load pull template schematic and a data display page and simulates.

License Requirements: Load Pull (LPL_100)

  1. View the "Load_Pull_Template" schematic and note the new HBTUNER3 element that provides baseband impedance control for two-tone and modulated signal load pull and an unlimited number of harmonics.
  2. Start Load Pull by choosing Scripts > Load Pull > Load Pull.
  3. Note the new Fm (and 4th/5th harmonic) options for load or source pull.
  4. Click Cancel in the Load_Pull_Template Gamma Sweeps dialog box.
  5. The contours in the data display show the high side/low side sensitivity to pre-simulated baseband impedance sweep.
  6. Double-click the "Input Power vs. Index" graph to activate the view and drag the m1 marker up and down to change the input power.

Easily Set Up PA Model Reuse

This project illustrates improvements to the AMP_F file-based amplifier, which now supports two types of data files.

License Requirements: VSS Time Domain (VSS_250+)

  1. AMP_F is updated to handle data files that were supported only by the NL_F block, which is now obsolete.
  2. The first data format, used in the data file "AMP_Behavioral_Params", defines frequency-dependent behavioral parameters (for example: gain, P1dB, NF, and IP3). The format can also include temperature dependency, which is implemented by placing VAR temp=X at the beginning of each section of the file; this example includes three temperature settings. The "Amp Model w Behavioral Params" system diagram uses the variable TEMP to define the simulation temperature and is swept using the SWPVAR block. A range of frequencies is defined in the system diagram options dialog box on the RF Frequencies tab. The Gain and Noise Figure are measured using the RFB simulation and are plotted in the "Behavioral Params Gain" and "Behavioral Params NF" graphs.
  3. The second data format, used in the "AMP_Pin_Pout" data file, defines the power-in power-out relationship (the AM/AM and AM/PM characteristics of a device). This format can also account for frequency dependency, which is achieved by placing VAR FREQ = Y before each AM/AM/PM data set. This example illustrates a device specified by its AM/AM/PM characteristics over three frequencies. The "Amp Model w Pin Pout Model" system diagram illustrates a different method of characterizing the device by using a VNA to sweep the power and frequency of the source and measure the device response. The AM-to-AM characteristic of the device is plotted in the "Pin Pout AM to AM" graph using both RFB and Time Domain measurements. AM-to-AM curves are plotted for various frequencies, as defined in the VNA.
  4. See the AMP_F Help and the VSS Getting Started Guide for more information.

Inspect System Diagrams for Damage from Overdriving the Devices

This project shows how to use the new cascaded damage indicator measurement, C_DAMAGE, in VSS.

License Requirements: VSS RF Budget (VSS_150+)

  1. C_DAMAGE computes cascaded operating point headroom relative to a power level at which damage is considered to occur at block input ports using the VSS RF Budget Analysis simulator. C_DAMAGE is similar to C_HDRM except that instead of comparing the input power to the 1 dB compression point, it is compared against a threshold above which damage is considered to occur, referred to as PIN_MAX. Such values are specified for individual blocks by adding a user attribute named PIN_MAX.
  2. You can add a UATTR annotation to the system diagram (from the Annotate > Attributes folder) to highlight the block(s) operating at input levels exceeding their respective PIN_MAX settings.
  3. This example project consists of a cascade of two PAs driven with a PORT_SRC at 0 dBm. The PIN_MAX attribute is set to 8 dBm for both PAs in the cascade. The second PA is highlighted to show that it is operating above its defined PIN_MAX setting, and the simulation results show that it is driven approximately 1.2 dB beyond that level.
  4. See the AWR Microwave Office Measurement Help for more information.

Evaluate Device Linearization before Building it? / Test Drive Classic or Commercial DPD Algorithms?

This example illustrates linearization of a PA using the new DPD block in VSS.

License Requirements: VSS Time Domain (VSS_250+)

  1. The new DPD block offers several classic Digital Pre-Distortion algorithms such as Memory Polynomials and Generalized Memory Polynomials.
  2. This example shows an OFDM signal at 3.5 GHz configured to simulate a multi-user type operation. The signal is fed to a driver amp and then into a power amplifier implemented as a circuit schematic in Microwave Office.
  3. The DPD uses a feedback signal from the device output which, along with the source signal, is used for initial calculations of the selected algorithm and then for incremental updates. The block offers various solvers that can be used for the initial DPD setup.
  4. Results compare device performance with and without the DPD, showing improvements in spectral regrowth, IQ constellation distortion, and CCDF.
  5. Options for commercial DPD solutions are available, allowing you to run the same algorithms in simulations as in the lab.
  6. See the VSS System Block Help for more information.

V14

This page contains improvements to the AWR Design Environment for PA designers.

Create reusable data display pages for simulated and measured data.

Load Pull Reports

The project will open to the Load Pull Report Output Equation page and simulate.

  1. Change multiple Measurement data sources with a few clicks.
    • Double-click on the DOC_SET element to enter edit mode
    • Uncheck the Sample_SPL data file and check Sample_AB data file
    • Click OK and note that all the Graphs update to reflect the new data source
  2. Change multiple Measurements to plot multiple sources with a few clicks.
    • Double-click on the DOC_SET element to enter edit mode
    • Check both the Sample_SPL data file and Sample_AB data file
    • Click OK and note that all the graphs update to show the results from both data sources
  3. Reset to plotting data from a single source.
    • Double-click on the DOC_SET element to enter edit mode and uncheck the Sample_AB data file.
  4. Using variables in measurements
    • Double-click on the first measurement on the PAE and Output Power Contours at xdB Compressed graph and note that the data is aligned to the equation xdB compressed rather than specified with a number
  5. Tune (F9) on the xdB equation
    • Note that the contours and displayed gamma points update accordingly as the aligned gain compression changes.
  6. Tune (F9) on the Z0_Re and Z0_Im equations
    • Note that the normalization impedance for both Smith Charts change.

Interpolate load pull data using floating markers on the Smith Chart.

Floating Load Pull Markers

The project will open to show the Load Pull at Fixed Input Power Output Equation page and simulate.

  1. Note that the current input power is displayed as a red vertical line on the rectangular graph
  2. Double-click on the Smith Chart to activate the view and drag m1 to select an impedance
  3. Note that as m1 is changed the PAE and PLoad at the m1 impedance are displayed to the right of the Smith Chart under Results
  4. The rectangular graph shows PAE and PLoad vs. input power at the m1 impedance
  5. Tune on PIn_Tuner in the tuner to change the input power at which the contours are plotted
  6. If desired explore the Load Pull at Fixed Compression Report Output Equations document which shows a similar setup but at a fixed compression point rather than a fixed input power

Effortlessly plot any measurement vs. output power.

Plotting vs. Output Power with X_SWP

The demo opens the project, maximizes an Output Equations page, simulates

License requirements: Nonlinear simulator (MWO-2XX)

  1. Note the X_SWP blocks on the schematic that allow the user to specify what to plot (power, voltage, current), how to measure it (spectrum analyzer style, power meter style, etc.) and where to measure it.
  2. Double-click one of the Graphs to activate the view.
  3. Right-click on the blue trace measurement in the legend, choose Modify Measurement and note that it uses the old PlotVs measurement that requires one measurement definition for the x-axis and one measurement definition for the y-axis.
  4. Right-click on the red trace measurement in the legend, choose Modify Measurement, and note that it is a "normal" measurement for which you can plot vs. output power by choosing the appropriate X_SWP_ID in the PORT_1 sweep drop down.
  5. If desired, inspect all the graphs in the Report One Tone and Report Two Tone Output Equation pages to explore different X_SWP configurations.

Jump-start matching network design using the Network Synthesis Wizard.

Matching Network Wizard Overview

The Network Synthesis Wizard allows the user to specify goals and components to generate matching network topologies in a matter of minutes. In this example a PA matching network is designed to meet both PAE and output power at a fixed compression point goals.

Additional Network Synthesis Wizard examples can be found on the antenna and design flow pages.

The project will open to show the Matching Network Report Output Equations page and simulate.

License requirements: Network Synthesis (SWS-100)

  1. Open the Example instance of the Network Synthesis Wizard and review the setup on each tab
    • Synthesis Definition - defines the "direction" of the matching network and frequency band(s) of interest.
    • Components - defines the available series and shunt components as well as first component and last component limitations.
    • Parameter Limits - defines the parameter limits, parameter rounding, component series, etc. for each component.
      • Note that the L and C are limited to the E24 value table and that the MLIN values round to 1 mil.
    • DC & Bias Feed - defines the matching network DC path constraints and the bias injection network that the wizard should consider.
      • Note that because this is a PA output matching network Port B must be a DC open to ground
    • Goals - defines the Measurements and Goals for the synthesis. Double-click on a Measurement or Goal to see the setup.
      • Note that the examples in this measurement use the load pull data as the source and define PAE and Output Power at 1 dB Compressed.
      • The goals are set up for a PAE >= 63%, an Output Power >= 51 dBm, and a 2nd and 3rd harmonic region.
      • Select the HarmAreaMatch goal and then push the View Region button to see the specified harmonic region.
    • Search Options - defines advanced search options.
    • Results - shows the results from the Synthesis run and controls how many network and what additional data is sent back to Microwave Office.

Synthesizing and sending results to Microwave Office

  1. NOTE: This synthesis takes a few minutes to run so there are results already saved in the project. However, if interested, push the Synthesize button to start a new synthesis. Otherwise skip to the next step to use the already synthesized results.
    • If you'd like to see an example that synthesizes more quickly check out the example on the design flow page.
  2. When the synthesis is complete (or if you skipped the synthesis step) push the To MWO button to send the results to Microwave Office.
  3. Push the OK button on the "Overwrite Options" dialog.
  4. Push the Close button to close the Wizard.

Exploring results

  1. All of the generated networks have been sent to Microwave Office and placed in the <Output_Match_synth> User Folder in the Project Tree.
  2. Click on the individual networks under the User Folder to see the results from the networks.
  3. Note that the graph results update to show response with the selected network and the displayed schematic updates to show the selected networks

V13

This page contains improvements to the AWR Design Environment for PA designers.

Perform advanced PA validation by analyzing the impact of source impedance and harmonic impedances.

Source Pull

The project will open to the source pull data-display page and simulate.

  1. Drag the markers around as indicated on the on screen instructions to explore the source pull data.

Harmonic Load Pull

The project will open to the advanced contrours data-display page and simulate.

  1. Drag the markers around as indicated on the on screen instructions to explore the impact of the second and third harmonic on performance.

Guarantee your PA performance with modulated-signal load pull.

Load Pull with Modulated Signals

The project will open to show the System Load Pull Template used to generate the modulated signal load pull data and the resulting ACPR contours.

  1. Point out the Load_Pull_System_Template is used to perform modulated signal load pull with the Load Pull Script.
  2. The ACPR contours are from an already simulated modulated signal load pull.
  3. Reference the Design Notes for more information on system load pull.

Verify PA performance with modulated signals directly in Microwave Office.

Circuit Envelope

The demo opens the project, tiles the windows, and simulates to show a multi-carrier QPSK source simulated using APLAC circuit envelope.

License requirements: Circuit Envelope (APL-110)

  1. Note that Circuit Envelope allows data to be plotted in either the frequency domain or the time domain.