Power Amplifier Circuit Resonance Tuning for Wideband DPD Linearity
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Solution Overview
Problem
Existing power amplifier designs and digital pre-distortion (DPD) linear designs fail to meet the requirements of modern wireless communication protocols, particularly in supporting large signal bandwidths and improving linear performance of DPD correction.
Innovation Solution
A power amplifier circuit is introduced, comprising a power amplifier unit and a broadband improvement unit. The broadband improvement unit adjusts the parallel resonance frequency of the power amplifier unit, reducing envelope impedance between specific target frequencies to increase video bandwidth and enhance DPD linearity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a broadband external matching design is used in an external circuit of the power amplifier device, then broadband performance is improved, but the video bandwidth remains small and linear performance of DPD correction is insufficient
Solution Approach 1:
The patent applies local quality by implementing an internal matching network specifically at the output end of the power amplifier device. This local modification targets the specific area where impedance matching is most critical for improving video bandwidth and linear performance, rather than relying solely on external matching circuits. The internal matching network is designed with specific inductance and capacitance values to create a low-pass filter effect that reduces envelope impedance in the target frequency range.
Solution Approach 2:
The patent embeds the matching network directly inside the package of the power amplifier device, creating a nested structure where the matching components are integrated within the device housing. This integration allows the internal matching network to work in conjunction with the external matching circuit, providing multiple layers of impedance optimization. The nested design reduces parasitic inductance and improves the overall video bandwidth by combining internal and external matching approaches.
2Adaptability or versatility
If the power amplifier device supports a large signal bandwidth, then more frequency bands can be supported, but the video bandwidth and linear performance of DPD correction cannot satisfy protocol requirements
Solution Approach 1:
The patent employs parameter changes by carefully selecting and optimizing the inductance and capacitance values of the matching network components. The inductor is designed with a specific inductance value (e.g., 0.5-2.0 nH) and the capacitor with a specific capacitance value (e.g., 0.1-1.0 pF) to create a low-pass filter with a cutoff frequency that provides low envelope impedance in the target frequency range. These parameter optimizations enable the device to maintain high video bandwidth precision while supporting wide signal bandwidths across multiple frequency bands.
3Reliability
If internal matching design is used inside the output of the power amplifier device, then video bandwidth can be increased, but device complexity increases
Solution Approach 1:
The patent merges the matching network with the existing output structure of the power amplifier device. The inductor is connected in series between the output terminal and the external matching circuit, while the capacitor is connected in parallel to ground, integrating these components into the existing circuit topology. This merging approach minimizes additional complexity by utilizing the existing package structure and bonding wires, rather than adding completely separate matching circuits.
Solution Approach 2:
The internal matching network is designed to serve multiple functions simultaneously: it provides impedance matching for wideband operation, acts as a low-pass filter to reduce high-frequency noise, and improves the linear performance of DPD correction. This multi-functionality reduces the need for separate circuits for each function, thereby limiting the increase in device complexity while achieving multiple performance improvements.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The proposed solution effectively increases the video bandwidth of the power amplifier circuit and improves the linear performance of DPD correction, while ensuring radio frequency performance is maintained.
Implementation Method 1
The broadband improvement unit is configured to adjust a parallel resonance frequency of the power amplifier unit
Data Source
AI summary
A power amplifier circuit includes a power amplifier unit and a broadband improvement unit. The power amplifier unit includes a signal input port, a signal output port, a power transistor, and a first inductor. The power transistor is configured to perform power amplification on radio frequency signals in a plurality of frequency bands. The broadband improvement unit adjusts a parallel resonance frequency of the power amplifier unit, to reduce envelope impedance of the power amplifier unit between a first target frequency and a second target frequency. The first target frequency is a maximum frequency difference between the plurality of frequency bands, and the second target frequency is a minimum frequency difference between the plurality of frequency bands.