Simulate LINC system in ADS Song 03/30/2005

What is the LINC? There are many linearization techniques. 1. Feed-forward 2. Pre-distortion 3. 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.

The use of power efficient amplifiers can provide significant improvement in the PAE of the overall system. Fig1:Simplified block diagram for an outphasing power amplifier

Fig2:Separation of two component signals from the source signal S1(t) and S2(t) are the modulated phase and constant amplitude signals

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.

ADS simulation LINC at system level

ADS simulation results (ideal)

ADS simulation (non-ideal)

ADS simulation non-ideal results

The class D power amplifier Use the Load-Pull technology to match the output port

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.

The phase detector

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

Phase shifter

Wide band 90 degree lumped hybrid

Reconfigurable transformer

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.

Several Technology to improve the LINC

ELINC

Next stage: Combine the feedback technology and the ELINC technology. Figure out the reconfigurable power combiner.

THANK YOU!