Notch-Filtered Doherty Amplifier for Wider Band Operation
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Solution Overview
Problem
Existing Doherty amplifier circuits operate within a narrow band due to the use of impedance converters and phase adjusters, which restrict their broadband capabilities.
Innovation Solution
The proposed Doherty amplifier circuit includes a division node that splits the input signal into multiple paths, a main amplifier, peak amplifiers, a combination node, and a notch filter connected between the division node and the first peak amplifier. This configuration allows for the suppression of signals at the center frequency, enabling a wider operational band.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If impedance converters and phase adjusters are used in the Doherty amplifier circuit, then the amplifier can operate within a stable band, but the operational bandwidth becomes narrow
Solution Approach 1:
The patent removes the impedance converter from the circuit configuration. By extracting this component that was causing the bandwidth limitation, the amplifier achieves broadband operation while maintaining stability through alternative circuit design approaches
Solution Approach 2:
Instead of using traditional impedance converters and phase adjusters to achieve stability, the patent inverts the approach by using a notch filter to suppress specific frequencies and redesigning the signal distribution network to inherently provide both stability and broadband operation
2Adaptability or versatility
If a notch filter is added to suppress center frequency signals, then the broadband capability is enhanced, but the device complexity increases
Solution Approach 1:
The notch filter is integrated into the signal distribution network to serve multiple functions: it suppresses center frequency signals to enable broadband operation while simultaneously acting as part of the overall signal routing and impedance matching structure, reducing the need for separate dedicated components
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
The described configuration achieves a wider band operation by balancing the power distribution across the operating band, reducing the absolute differences in output power at the center frequency and the band edges, thereby enhancing the broadband capabilities of the Doherty amplifier circuit.
Implementation Method 1
a notch filter that is connected between the division node and the first peak amplifier and suppresses a signal at a center frequency of an operating band
Data Source
AI summary
A Doherty amplifier circuit includes a division node that divides an input signal into a first signal and a second signal, a main amplifier that amplifies the first signal and outputs an amplified first signal as a third signal, a first peak amplifier that amplifies the second signal and outputs an amplified second signal as a fourth signal, a combination node that combines the third signal and the fourth signal and outputs a combined signal to an output terminal as an output signal, and a notch filter that is connected between the division node and the first peak amplifier and suppresses a signal at a center frequency of an operating band.