Simulate LINC system in ADS

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Simulate LINC system in ADS

• Song Lin _at_ECE.UTK 03/30/2005

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What is the LINC?

• There are many linearization techniques.
• Feed-forward
• Pre-distortion
• LINC
• Linear amplification using nonlinear
  components
• (LINC) is a technique whereby a linear
  modulation
• signal is converted into two constant
  envelope signals
• that are independently amplified by
  power-efficient
• Class D amplifiers and then combined using
  a hybrid
• coupler.

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Fig1Simplified block diagram
for an outphasing power amplifier

• The use of power efficient amplifiers can
  provide significant improvement in the PAE of
  the overall system.

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Fig2Separation of two component
signals from the source signal
S1(t) and S2(t) are the modulated phase and
constant amplitude signals
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The problem we want to solve

1. The Class D Power amplifier.
2. The reconfigurable Combiner.
3. The phase detector.
4. The phase shifter.
5. The amplitude detector.
6. The DSP part.

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ADS simulation LINC at system level
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ADS simulation results (ideal)
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ADS simulation (non-ideal)
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ADS simulation non-ideal results
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The class D power amplifier

• Use the Load-Pull technology to match the
  output port

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• Use S parameter to match the input port

To simplify the design, I chose the narrow band
system working around 850MHz. To design the
wideband PA, there is another way to go for
matching.
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The phase detector
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• Use the MCU to control the comparing time, and
  then get the relationship of the phase different
  and the voltage. After getting the voltage, we
  can use the MCU to control the analogy phase
  shifter to balance the phase of the two branches

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Phase shifter
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Wide band 90 degree lumped hybrid
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Reconfigurable transformer
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• For the reconfigurable transformer, we still
  have a long way to go. I think we can use the
  switch to make the transmission line transformer
  to be reconfigurable. Although this kind of
  reconfigurable transformer can get very high
  efficiency but it has very poor isolation between
  the two input port. So we should find the best
  point to meet the requirement.

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Several Technology to improve the LINC
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ELINC
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Next stage

• Combine the feedback technology and the ELINC
  technology.
• Figure out the reconfigurable power combiner.

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• THANK YOU!