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Design Notes
Power Added Efficiency Measurement
Many customers ask exactly how the Power Added Efficiency (PAE) is calculated in the AWR Design Environment. This example will demonstrate through equations exactly how PAE is calculated and discuss some common issues.
Overview
PAE is loosely defined as 100*(Pout-Pin)/Pdc. This definition does not tell you exactly how each variable is defined, so each variable is explained in more detail below.
1. Pout is the output power in the fundamental tones, not the total power.
2. Pin is the power delivered to the network, NOT the power available from the source.
3. Pdc is the DC power from all sources in the circuit.
For Pout, the fundamental tone power causes problems if you are using a PORTMOD element to inject a modulated signal into the circuit. There is a 2nd PAE measurement called PAEB that allows the user to specify the frequency range to calculate the input and output powers. This measurement should be used when using a complex signal in the simulation.
For Pin, some designers want to see PAE calculated with the power available rather than the power delivered. The easiest solution is to use an ISOL8R element directly after the input port. This will effectively use power available for PAE.
All of these different issues are demonstrated in this project.
Global Settings
For each schematic, the impedance at the input of the circuit and the input power are defined as equations in the global equations. Changes here will apply to all schematics in this project.
One Tone PAE
The One_Tone schematic is the setup for PAE for a single tone input source. The PAE from this simulation is calculated in the Output Equations and compared with the PAE measurement on the PAE One Tone Calculated Vs Measured graph. Notice the values are identical.
Two Tone PAE
The Two_Tone schematic is the setup for PAE for a two tone input source. The PAE from this simulation is calculated in the Output Equations and compared with the PAE measurement on the PAE Two Tone Calculated Vs Measured graph. Notice the values are identical.
One Tone Power Available PAE
The One_Tone_Power_Available schematic is the setup for PAE for a single tone input source where power available is used for PAE. In this case an ISOL8R element won't allow power reflected from the device back to the input port, so the power measured at the input port will be nearly identical to the power available (value set) on the port. The tuner at the input of the device in this example is set to not be matched to show this effect. See the Input Power graph to see that for this schematic, the input power is the power set on the port, but not for the other schematics without the ISOL8R. Then notice that the values on the Output Power graph are similar. Finally, the PAE graph compares the PAE from the three cases listed above and you can see the PAE for power available case is lower than the others, which is expected since the input power is greater for this case.
PORTMOD PAE
The PORTMOD schematic is the setup for PAE for a modulated signal input source. The same concepts will apply for any source that has significant power at harmonics other than the fundamentals. The PAE from this simulation using the PAE and the PAEB measurements is shown on the PAE PORTMOD graph. Notice the PAEB measurement is similar to the PAE measurements for the one and two tone cases.
Schematic - One_Tone
Graph - PAE Two Tone Calculated Vs Measured
Frequency (GHz) | PAE(PORT_1,PORT_2) Two_Tone.AP_HB | Re(Eqn(tPAE)) Output Equations |
---|---|---|
10 | 10.0493 | 10.0493 |
Graph - PAE One Tone Calculated Vs Measured
Frequency (GHz) | PAE(PORT_1,PORT_2) One_Tone.AP_HB | Re(Eqn(PAE)) Output Equations |
---|---|---|
10 | 10.131 | 10.131 |
Graph - PAE
Frequency (GHz) | PAE(PORT_1,PORT_2) Two_Tone.AP_HB | PAE(PORT_1,PORT_2) One_Tone.AP_HB | PAE(PORT_1,PORT_2) One_Tone_Power_Available.AP_HB |
---|---|---|---|
10 | 10.0493 | 10.131 | 8.50652 |