Doherty Amplifier Partition Wall Layout for Path Isolation
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Solution Overview
Problem
Doherty amplifiers face issues with isolation deterioration and oscillation due to adjacent main and peak amplifiers, which can be exacerbated by electromagnetic coupling, and existing solutions like electrical shields increase manufacturing costs.
Innovation Solution
A Doherty amplifier design featuring a resin substrate with a partition wall and inductors mounted on a heat sink, dividing the cavity and providing electromagnetic shielding without additional components or assembly steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dedicated electrical shield member is added between the main amplifier and peak amplifier paths, then the isolation between paths is improved, but the manufacturing cost increases due to additional components and assembly steps
Solution Approach 1:
The patent merges the shielding function with the existing resin substrate by incorporating a conductive layer (ground pattern) into the substrate structure. This integration eliminates the need for separate shield members and their assembly, thereby improving isolation between main and peak amplifier paths while avoiding additional manufacturing costs
Solution Approach 2:
The resin substrate is given multiple functions: it serves as both the structural support for mounting amplifiers and as the electromagnetic shield through its integrated ground pattern. This multi-functionality eliminates the need for dedicated shield components, resolving the contradiction between improved isolation and manufacturing cost
2Volume of moving object
If the main amplifier and peak amplifier are disposed adjacent to each other to reduce size and cost, then the device size and manufacturing cost are reduced, but the isolation between paths deteriorates leading to potential oscillation and characteristic deterioration
Solution Approach 1:
The patent introduces a ground pattern (conductive layer) as an intermediary between the main amplifier and peak amplifier mounted on the resin substrate. This ground pattern acts as an electromagnetic barrier that maintains path isolation even when amplifiers are disposed adjacent to each other, enabling compact design without sacrificing reliability
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
Improves isolation between main and peak amplifiers, reducing electromagnetic coupling and oscillation risks at a lower cost by utilizing existing chip inductors and capacitors, maintaining operational stability and efficiency.
Implementation Method 1
the plurality of metal layers of the partition wall part are electrically connected to the heat sink
Implementation Method 2
a heat sink; a resin substrate mounted on the heat sink
Data Source
AI summary
A Doherty amplifier according to an aspect of the present disclosure includes a heat sink; a resin substrate mounted on the heat sink, and having a cavity formed to expose the heat sink, the resin substrate being formed by stacking a plurality of resin layers and a plurality of metal layers; a main amplifier mounted in the cavity; a peak amplifier mounted in the cavity; and an inductor, wherein the resin substrate has a partition wall part that separates at least a portion of the main amplifier from at least a portion of the peak amplifier, the plurality of metal layers of the partition wall part are electrically connected to the heat sink, and the inductor is mounted on the partition wall part, and electrically connected to the plurality of metal layers.