Examples > RF Board > Load Pull
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Lange CouplerLow Power Mixer for Pagers

Load-Pull Simulations

Location: /examples/RF_Board/LoadPull_prj

Objective

Shows how to do load-pull simulations to generate contours that indicate load impedances. These contours cause a certain power to be delivered to the load when they are presented to the output of a device along with the specified source impedances and available source power.

Setup

  1. "HB1Tone_LoadPull" is a simulation set-up that generates actual contour lines for output power and power-added efficiency.

  2. "HB2Tone_LoadPull" is identical to "HB1Tone_LoadPull" except that it shows all the equations, and includes some explanatory text.

  3. "HB1Tone_LoadPull.dds" displays the output power and power-added efficiency contours and includes information on the equation syntaxes.

  4. "ReflectionCoefUtility.dds" shows how the variables s11rho and s11center determine the circular region of the Smith Chart within which load reflection coefficients are generated.

  5. "HB1Tone_LoadPullMagPh" is identical to "HB1Tone_LoadPull", except that it uses a much simpler simulation setup. Instead of generating loads in a circular region of the Smith chart, the magnitude and phase of the load reflection coefficient are swept independently.

  6. "HB1Tone_LoadPull_ConstPdel" uses an optimization to vary parameters on the schematic until a desired power is delivered to each load impedance. Contours of constant power-added efficiency and constant bias current are plotted on the data display.

  7. "LoadPullMagPh_ConstPdel" is similar to "HB1Tone_LoadPull_ConstPdel", except that it varies the magnitude and phase of the load reflection coefficient rather than sweeping out a circular region of the Smith chart. Also the data display has contours of constant operating and transducer power gain.

  8. "HB2Tone_LoadPull" is a simulation set-up that generates actual contour lines for output power, power-added efficiency, third-order intermodulation distortion, and fifth-order intermodulation distortion.

  9. "HB2Tone_LoadPull.dds" has the contour plots on one page, and the equations used to calculate output power, power-added efficiency, third-order intermodulation distortion, and fifth-order intermodulation distortion on another.

  10. "HB2Tone_LoadPullMagPh" is identical to "HB2Tone_LoadPull", except that it uses a much simpler simulation setup. Instead of generating loads in a circular region of the Smith chart, the magnitude and phase of the load reflection coefficient are swept independently.

  11. "contours" shows the old method of generating load pull contours, that was used in ADS before release 1.3. It generates load-pull contours on a Smith chart. These contours indicate load impedances that, when presented to the output of a device (along with the specified source impedances and available source power), would cause a certain power delivered to the load. "contours.dds"is the corresponding data display.

Load pull schematic

Analysis

Output and PAE setup

Figure 1: Output power and PAE set-up.

Load Tuner equation

Figure 2: Load Tuner equation.

Sweep equation

Figure 3: Fundamental Load Tuner coverage and sweep equation.

Notes

  • Simulation controller used: Harmonic Balance.

  • Only the impedance at the fundamental frequency is varied. Impedances at harmonic frequencies are set independently but they are not varied in this example. Detailed information on setting up the load and source impedances for the load-pull can be found in the example descriptions.