Load-Modulated Balanced RF Power Amplifier Without Matching Circuit
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Solution Overview
Problem
The insertion of an impedance matching circuit between the control amplifier and the hybrid coupler in load-modulated balanced amplifiers hinders the miniaturization and wider bandwidth of radio frequency power amplifiers.
Innovation Solution
A radio frequency power amplifier design that includes a hybrid coupler with a first, second, third, and fourth port, where the output end of the balanced amplifier is coupled to the third port without any impedance-matching circuit components, and a common power supply voltage is used for both the balanced and control amplifiers, allowing the hybrid coupler to change the load impedance based on the current level of the control amplifier's input signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If an impedance matching circuit is inserted between the control amplifier and the hybrid coupler, then the balanced amplifier and control amplifier can operate at high power-added efficiency with a single power supply, but the device size increases and bandwidth is reduced
Solution Approach 1:
The patent removes the impedance matching circuit from the signal path between the control amplifier and hybrid coupler. By extracting this component, the device size is reduced and bandwidth is improved, while the power-added efficiency is maintained through direct coupling of the control amplifier output to the hybrid coupler third port.
Solution Approach 2:
The patent merges the control amplifier output directly with the hybrid coupler third port without intermediate impedance matching circuits. This direct merging eliminates unnecessary components and their associated parasitic effects, achieving both miniaturization and broadband operation while maintaining high efficiency through proper load modulation.
2Use of energy by moving object
If an impedance matching circuit is inserted between the control amplifier and the hybrid coupler, then the balanced amplifier and control amplifier can operate at high power-added efficiency with a single power supply, but the bandwidth of the radio frequency amplifier is reduced
Solution Approach 1:
The patent extracts the impedance matching circuit from the control amplifier signal path. This removal eliminates the bandwidth limitations imposed by the matching circuit's frequency-dependent characteristics, enabling wideband operation while maintaining high power-added efficiency through direct load modulation of the balanced amplifier.
Solution Approach 2:
The patent employs dynamic load modulation through the hybrid coupler, where the control amplifier directly modulates the load impedance of the balanced amplifier across a wide frequency range. This dynamic approach eliminates the need for static impedance matching circuits that limit bandwidth, achieving both high efficiency and wide bandwidth through frequency-independent load modulation.
3Use of energy by moving object
If an impedance matching circuit is inserted between the control amplifier and the hybrid coupler, then the balanced amplifier and control amplifier can operate at high power-added efficiency with a single power supply, but the device becomes more complex
Solution Approach 1:
The patent extracts and removes the impedance matching circuit from the amplifier system. This elimination simplifies the overall circuit architecture by reducing the number of components, interconnections, and design parameters, while maintaining high power-added efficiency through the direct coupling of the control amplifier to the hybrid coupler.
Solution Approach 2:
The patent merges the control amplifier output directly with the hybrid coupler third port, eliminating intermediate impedance matching circuits. This merging simplifies the circuit topology, reduces component count, and lowers design complexity while preserving high efficiency operation through direct load modulation of the balanced amplifier.
Data Source
AI summary
A hybrid coupler has a first port, a second port, a third port, and a fourth port to which a load is connected. An input signal distributor distributes a first input signal that is a radio frequency signal into a second input signal and a third input signal. The second input signal is inputted to a balanced amplifier. The balanced amplifier outputs two amplified radio frequency signals with a phase difference of 90° from each other from two output ends, one of which is coupled to the first port and another one of which is coupled to the second port. The control amplifier amplifies the third input signal and outputs the amplified third input signal from an output end. The output end of the control amplifier is coupled to the third port without any circuit component affecting impedance matching disposed in between.