Wilkinson Power Divider Layout for Wideband Doherty Stability
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Solution Overview
Problem
Conventional Doherty amplifiers face issues with loop oscillation, requiring stabilizing circuits that increase size, and cannot amplify signals over a wide band due to increased resistance values in isolation resistors.
Innovation Solution
Incorporating a Wilkinson power divider with π-type low-pass filters and T-type high-pass filters, or vice versa, to suppress loop oscillation without additional stabilizing circuits while maintaining wide-band signal amplification capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the resistance value of the isolation resistor is increased to suppress loop oscillation, then loop oscillation is suppressed, but the passage characteristic of the desired band becomes narrow
Solution Approach 1:
The patent changes the resistance value of the isolation resistor to an optimal value that balances loop oscillation suppression with maintaining wide bandwidth passage characteristics. Instead of using a high resistance value that narrows the bandwidth, the patent identifies and applies a specific resistance value that achieves both goals simultaneously.
2Reliability
If a stabilizing circuit is mounted to suppress loop oscillation, then loop oscillation is suppressed, but the circuit size increases
Solution Approach 1:
The patent extracts the stabilizing circuit from the system by using an isolation resistor with an optimized resistance value that inherently suppresses loop oscillation without requiring additional stabilizing circuitry. This removes the need for extra components while maintaining reliability.
3Reliability
If the resistance value of the isolation resistor is increased, then loop oscillation is suppressed, but the signal cannot be amplified over a wide band
Solution Approach 1:
The patent optimizes the resistance value parameter of the isolation resistor to achieve a balance between loop oscillation suppression and wide-band signal amplification capability, enabling the amplifier to maintain both stability and broad frequency response.
Data Source
AI summary
A Wilkinson power divider includes: π-type LPFs connected to an input terminal; a T-type HPF having one end connected to one of the π-type LPFs and having another end connected to a carrier amplifier; another T-type HPF having one end connected to another one of the π-type LPFs and having another end connected to a λ/4 line; and an isolation resistor connected to connection points.