Multi-beam Outphasing Transmitter for Phased Array Efficiency
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Solution Overview
Problem
Phased array antenna panels face inefficiencies in transmitting RF signals with time-varying amplitudes, leading to increased error vector magnitude and unintended beam directions, particularly in high-frequency applications, due to the use of power amplifiers that introduce distortion and non-linearity.
Innovation Solution
The implementation of a multi-beam outphasing transmitter that decomposes variable amplitude signals into constant amplitude signals, which are then amplified using separate power amplifiers, minimizing inter-modulation and interference, and transmitted using dual-polarized antennas to reduce grating lobes and improve power efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If power amplifiers are used to amplify RF signals with time-varying amplitude, then spectral efficiency is improved, but distortion and non-linearity increase
Solution Approach 1:
The variable amplitude RF signal is decomposed into two constant amplitude signals (in-phase and quadrature components) that are amplified separately by two power amplifiers. This segmentation allows each amplifier to operate in its linear region while maintaining spectral efficiency, resolving the contradiction between productivity and manufacturing precision.
Solution Approach 2:
The invention changes the amplitude parameter of the RF signal from variable to constant by decomposing it into two constant amplitude components. This parameter transformation enables the power amplifiers to operate efficiently without introducing distortion, simultaneously achieving high spectral efficiency and low signal distortion.
2Loss of energy
If constant amplitude signals are used for amplification, then power efficiency is improved and distortion is reduced, but spectral efficiency decreases
Solution Approach 1:
Two constant amplitude signals (in-phase and quadrature components) are combined after amplification to reconstruct the original variable amplitude RF signal. This merging process maintains the power efficiency and low distortion benefits of constant amplitude amplification while restoring the spectral efficiency of the original signal.
Solution Approach 2:
The invention transitions from a single-dimensional constant amplitude signal to a two-dimensional signal space by introducing quadrature components. This dimensional expansion allows the system to achieve both power efficiency through constant amplitude operation and spectral efficiency through the combined effect of in-phase and quadrature components.
3Adaptability or versatility
If phased array antenna panels transmit multiple RF beams, then communication coverage is improved, but grating lobes increase causing interference
Solution Approach 1:
The invention introduces dual-polarized antennas as an intermediary between the power amplifiers and the radiation environment. By utilizing orthogonal polarizations, the system can transmit multiple RF beams with reduced mutual interference and suppressed grating lobes, achieving improved communication coverage without harmful interference.
Data Source
AI summary
An outphasing transmitter includes a combiner, a decomposition block, first and second power amplifiers, and antennas in a phased array antenna panel. The combiner combines a plurality of beamforming signals into a composite input signal. The decomposition block decomposes the composite input signal into first and second decomposed radio frequency (RF) signals coupled to the first and second power amplifiers. Non-overlapping sub-arrays of the antennas may be uniquely associated with the first and second power amplifiers. Alternatively, groups of interleaved antenna rows may be uniquely associated with the first and second power amplifiers. Alternatively, random pluralities of the antennas may be randomly hard-wired to the first and second power amplifiers. Alternatively, pluralities of the antennas may be dynamically and selectably assigned to the first and second power amplifiers. The phased array antenna panel forms a plurality of RF beams corresponding to the plurality of RF beamforming signals.