Doherty Amplifier Shunt Inductance for Signal Coupling Reduction
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Solution Overview
Problem
Doherty amplifier designs face challenges in minimizing signal coupling between carrier and peaking amplifier paths, especially at higher frequencies, due to the need for close proximity of components, which hinders miniaturization and performance optimization.
Innovation Solution
Incorporating shunt inductance circuits coupled to the carrier and peaking amplifier drains to increase the electrical length of transmission lines, allowing for greater physical separation of components while maintaining performance, and enabling easier tuning and resonance of parasitic capacitances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If discrete devices and components are used for carrier and peaking amplifier paths, then signal coupling between paths is reduced, but device size and complexity increase
Solution Approach 1:
The patent combines the carrier and peaking amplifier paths into a single integrated device package, merging previously discrete components into a unified structure that reduces overall device complexity while maintaining performance
Solution Approach 2:
The patent introduces a ground isolation structure as an intermediary element between the carrier and peaking amplifier paths. This ground isolation structure acts as a mediator that reduces signal coupling between the paths while allowing the amplifiers to be positioned closer together, thereby reducing device complexity
2Object-affected harmful factors
If discrete devices are maintained at a distance apart, then signal coupling is reduced, but device area increases
Solution Approach 1:
The patent utilizes vertical dimension by implementing a ground isolation structure that provides electrical isolation between carrier and peaking amplifiers in the vertical direction. This allows the amplifiers to be positioned closer in the horizontal plane, thereby reducing device area while maintaining signal coupling reduction
Solution Approach 2:
The ground isolation structure serves as an intermediary that enables closer positioning of amplifier components. By providing isolation through the vertical ground path, the amplifiers can be placed nearer horizontally, reducing the overall device footprint
3Area of stationary object
If amplifier paths are positioned close together, then device size is reduced, but signal coupling increases
Solution Approach 1:
The ground isolation structure is positioned between the carrier and peaking amplifier paths to act as an intermediary barrier. This structure provides electrical isolation that prevents signal coupling while allowing the amplifiers to be positioned close together, enabling device miniaturization without performance degradation
Solution Approach 2:
The patent segments the device package into distinct isolation regions using ground isolation structures. This segmentation creates separate electrical zones for carrier and peaking amplifiers, preventing signal coupling while maintaining compact overall device dimensions
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
This configuration reduces signal coupling, enables miniaturization, and maintains high performance and efficiency even at higher frequencies, allowing for more compact and effective Doherty amplifier designs.
Implementation Method 1
shunt inductance circuits coupled to the carrier and peaking amplifier drains to increase the electrical length of transmission lines, allowing for greater physical separation of components while maintaining performance, and enabling easier tuning and resonance of parasitic capacitances
Data Source
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AI summary
A Doherty amplifier module includes first and second amplifier die. The first amplifier die includes one or more first power transistors configured to amplify, along a first signal path, a first input RF signal to produce an amplified first RF signal. The second amplifier die includes one or more second power transistors configured to amplify, along a second signal path, a second input RF signal to produce an amplified second RF signal. A phase shift and impedance inversion element is coupled between the outputs of the first and second amplifier die. A shunt inductance circuit is coupled to the output of either or both of the first and/or second amplifier die. Each shunt inductance circuit at least partially resonates out the output capacitance of the amplifier die to which it is connected to enable the electrical length of the phase shift and impedance inversion element to be increased.