Doherty Amplifier Package With Ground Shielding
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Solution Overview
Problem
Doherty amplifiers face challenges in finely adjusting characteristics while suppressing electromagnetic coupling, especially when components are packaged together, leading to reduced size and efficiency issues.
Innovation Solution
Incorporating delay circuits within the package to synchronize phases between input and output terminals, along with external matching circuits for fine adjustment, helps reduce electromagnetic coupling and maintain efficiency even at smaller package sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the Doherty amplifier is integrated into one package to reduce size, then the package size is reduced, but electromagnetic coupling between adjacent terminals increases affecting device characteristics
Solution Approach 1:
A ground structure is introduced as an intermediary element between the adjacent input terminals and output terminals within the package. This ground structure acts as a shield to reduce electromagnetic coupling between the terminals, enabling compact packaging while maintaining signal integrity. The ground structure is connected to the reference potential and positioned to effectively block electromagnetic interference between adjacent high-frequency terminals.
2Volume of moving object
If all components are packaged together to reduce size, then the package size is reduced, but fine adjustment of characteristics becomes difficult
Solution Approach 1:
The Doherty amplifier is divided into two separate semiconductor devices, each containing one amplifier, which are then mounted on a circuit board within the package. This segmentation allows the amplifiers to be manufactured and tested independently with precise characteristics, while still achieving compact packaging when mounted together on the shared circuit board with common power supply and ground connections.
3Length of stationary object
If the distance between adjacent terminals is reduced to decrease package size, then the package size is reduced, but electromagnetic coupling between terminals increases
Solution Approach 1:
The ground structure serves as a mediating element that enables reduced terminal spacing without increasing electromagnetic coupling. By positioning the ground structure between adjacent terminals, it provides electromagnetic shielding that allows the terminals to be placed closer together while maintaining isolation, thus reducing overall package size without sacrificing signal integrity.
Data Source
AI summary
A package (1) includes first and second input terminals (2,3) which are adjacent to each other, and first and second output terminals (4,5) which are adjacent to each other. A first input matching circuit (6), a first delay circuit (7), a second input matching circuit (8), a first amplifier (9), and a first output matching circuit (10) are sequentially connected between the first input terminal (2) and the first output terminal (4) inside the package (1). A third input matching circuit (11), a second amplifier (12), a second output matching circuit (13), a second delay circuit (14), and a third output matching circuit (15) are sequentially connected between the second input terminal (3) and the second output terminal (5) inside the package (1). First to fourth matching circuits (16-19) are respectively connected to the first input terminal (2), the second input terminal (3), the first output terminal (4) and the second output terminal (5) outside the package (1).