Doherty Amplifier Shunt Inductance High-Q Capacitor Resonance
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Solution Overview
Problem
Doherty amplifier designs face challenges in minimizing signal coupling between carrier and peaking amplifier paths, particularly at higher frequencies, due to the need for close proximity of components, which hinders miniaturization and performance at compact footprints.
Innovation Solution
Incorporating shunt inductance circuits coupled to the carrier and peaking amplifier drain terminals to increase the electrical length of the transmission line, allowing for greater physical separation of components and reducing coupling, while also enabling easier tuning and modification of inductance values without altering the amplifier layout.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If discrete devices and components are used to implement carrier and peaking amplifier paths, then amplifier performance and stability are improved, but device area and complexity increase
Solution Approach 1:
The patent combines multiple discrete components (inductors, capacitors, resistors) into integrated circuit implementations. The Doherty amplifier is realized using integrated circuits that incorporate the carrier amplifier, peaking amplifier, and associated passive components, thereby reducing the overall device area while maintaining the functional separation needed for performance and stability.
Solution Approach 2:
The patent implements a hierarchical integration structure where smaller functional blocks (amplifier stages, matching networks) are nested within larger integrated circuit packages. This allows multiple amplifier paths and their associated components to be compactly arranged in a nested configuration, reducing the footprint while preserving the necessary spatial relationships for performance.
2Object-affected harmful factors
If discrete devices are placed at significant spatial distances to reduce coupling, then signal coupling between carrier and peaking amplifiers is reduced, but device area increases
Solution Approach 1:
The patent introduces ground planes and shielding structures as intermediary elements between the carrier and peaking amplifier paths. These intermediaries act as electromagnetic barriers that reduce coupling between the amplifier paths, allowing them to be placed closer together without significant performance degradation, thereby reducing the overall device area.
Solution Approach 2:
The patent utilizes vertical stacking and three-dimensional integration to separate amplifier paths in the vertical dimension rather than requiring large horizontal distances. By arranging components in multiple layers with appropriate grounding and shielding between layers, the patent achieves coupling reduction while maintaining a compact planar footprint.
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 allows for the design of compact, high-performance Doherty amplifiers that maintain gain, linearity, and efficiency, even at higher frequencies, by reducing signal coupling and enabling longer physical distances between components.
Implementation Method 1
a shunt inductance circuit configured to at least partially resonate out an output drain-source capacitance of the transistor
Data Source
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 circuit is coupled to the output of either or both of the first and/or second amplifier die. The shunt circuit includes a series coupled inductance and high-Q capacitor (e.g., a metal-insulator-metal (MIM) capacitor), and the shunt circuit is configured to at least partially resonate out the output capacitance of the amplifier die to which it is connected.