IQ-Modulated Outphasing Amplifier for Wideband Phase Complementarity
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Solution Overview
Problem
Existing methods for creating phase-complementary drive signals for high-efficiency outphasing power amplifiers are complex and often narrow-band, requiring redesign of the RF path from baseband to antenna, and lack simplicity and standalone operation capabilities.
Innovation Solution
A system and method utilizing IQ modulators and a vector generator to produce phase-complementary RF signals, enabling standalone operation of outphasing power amplifiers by generating zero to ninety degree and zero to negative ninety degree variable phase shifted output signals, which are then amplified to produce complementary phase modulated signals, reducing complexity and hardware cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional methods are used to create phase-complementary drive signals for outphasing power amplifiers, then high efficiency and linearity can be achieved, but the system complexity and hardware cost increase significantly
Solution Approach 1:
The patent divides the phase-complementary signal generation into two separate IQ modulator paths (first and second IQ modulators) that independently generate phase-modulated signals. Each modulator handles a specific phase range (0 to +90 degrees and 0 to -90 degrees respectively), simplifying the overall signal generation architecture while maintaining the required phase complementarity for high-efficiency outphasing operation
Solution Approach 2:
The patent introduces a vector generator as an intermediary component that generates the quadrature vector signals (Q and -Q) needed by the IQ modulators. This mediator component simplifies the signal generation process by providing pre-processed vector inputs to the modulators, reducing the complexity of the overall system while enabling standalone operation
2Adaptability or versatility
If existing phase-complementary signal generation methods are implemented, then outphasing amplifier operation is possible, but the RF path requires complete redesign from baseband to antenna
Solution Approach 1:
The patent extracts the phase-complementary signal generation function from the baseband processing chain and implements it directly in the RF path using IQ modulators that accept RF drive signals. This extraction allows the amplifier to operate standalone without requiring redesign of the complete baseband to antenna RF path, as the phase modulation is performed directly on the RF signals
Solution Approach 2:
The IQ modulators are configured to process various types of modulated signals (AM, FM, PM, QAM) by accepting different I and Q input signals. This multi-functionality allows the same hardware architecture to handle diverse signal types without requiring separate processing paths, enhancing adaptability while maintaining a unified RF path design
3Measurement precision
If narrow-band phase-complementary signal generation is used, then specific frequency operation is achieved, but bandwidth is limited
Solution Approach 1:
The patent implements dynamic phase shifting within the IQ modulators where the phase of the output signals varies continuously based on the instantaneous values of the I and Q input signals. This dynamic phase adjustment mechanism allows the system to maintain accurate phase complementarity across a wide bandwidth, adapting to different frequency components and signal types without being constrained to narrow-band operation
Data Source
AI summary
A system may include a first IQ modulator configured to: based on an I and a Q, produce a zero to ninety degree variable phase shifted output signal that changes relative to an input envelope of an RF drive waveform of the RF drive. The system may include a first amplifier path configured to: output a first phase modulated signal. The system may include a second IQ modulator configured to: based on the I and the −Q, produce a zero to negative ninety degree variable phase shifted output signal that changes relative to the input envelope. The system may include a second amplifier path configured to: output a second phase modulated signal, wherein the second phase modulated signal is complementary to the first phase modulated signal. The system may include a vector generator configured to: generate the Q and the −Q for the first and second IQ modulators, respectively.