Spatial RF Combiner Using Outphased Constant-Envelope Amplification
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Solution Overview
Problem
The combination of electromagnetic signals often results in increased peak to average power ratio (PAPR), leading to nonlinear effects and distortion in power amplifiers, particularly when operating near compression points, which diminishes waveform performance.
Innovation Solution
A spatial combiner device with RF input connectors, constant envelope circuitry, power amplifier circuits, and spatial radiators that convert variable envelope signals into constant envelope signals, allowing for efficient amplification and combination of signals using broadband TEM propagation modes, thereby reducing nonlinear distortions and increasing power efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If electromagnetic signals are combined using traditional methods, then signal combination is achieved, but peak to average power ratio increases causing nonlinear distortion
Solution Approach 1:
The patent segments the signal combination process into multiple spatial paths. Instead of combining signals electrically in a single path, the invention uses multiple spatial radiators to transmit signals through different spatial paths and combines them in the far-field region, thereby avoiding the PAPR-induced nonlinear distortion that occurs in traditional electrical combining methods
Solution Approach 2:
The patent transitions from electrical signal combining (one-dimensional) to spatial signal combining by adding the spatial dimension. Multiple radiators are positioned at different spatial locations, and signals are combined in the far-field region through spatial superposition, effectively moving the combining operation from the electrical domain to the spatial domain
2Loss of energy
If power amplifiers operate near compression point for maximum efficiency, then power efficiency is improved, but intermodulation distortion increases
Solution Approach 1:
The patent segments the power amplification function across multiple independent power amplifiers, each driving a separate spatial radiator. This allows each amplifier to operate independently near its compression point for maximum efficiency, while the spatial separation prevents the intermodulation distortion from accumulating and degrading overall waveform performance
Solution Approach 2:
The patent introduces the spatial field as an intermediary medium between the power amplifiers and the combined output. Instead of directly combining amplified signals electrically (which would propagate distortion), the signals are radiated into the spatial field where they superpose naturally, allowing efficient amplification without distortion propagation
3Object-generated harmful factors
If constant envelope circuitry is used to convert variable envelope signals, then nonlinear distortion is reduced, but device complexity increases
Solution Approach 1:
The patent replaces the mechanical/electrical constant envelope circuitry with a spatial field-based solution. Instead of using complex electrical circuits to enforce constant envelope, the invention allows power amplifiers to operate in their natural nonlinear region and uses spatial superposition in the far-field to achieve distortion-free combining, effectively substituting electrical complexity with spatial simplicity
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 solution effectively reduces peak to average power problems, enables wider band amplification, and increases power amplifier efficiency, resulting in less heat generation and longer device lifespan, while maintaining high data rate capacity and efficient spectral usage.
Implementation Method 1
broadband TEM propagation modes
Data Source
AI summary
Spatially combining signals may include receiving a number of RF input signals at a number of RF input connectors. At least one of the RF input signals is a variable envelope signal. A variable envelope signal is converted into two or more outphased constant envelope signals. The two or more outphased constant envelope signals are amplified. The amplified outphased constant envelope signals are radiated. At a spatial combiner aperture, the radiated amplified outphased constant envelope signals are combined to create a combined signal. The combined signal is output onto an output RF connector.