Direct Spatial Antenna Modulation for RF Power Loss
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Solution Overview
Problem
Existing RF communication systems suffer from power loss and linearity issues due to the separation of RF modulating elements and antennas, requiring additional amplification and reducing maximum output power.
Innovation Solution
Direct Spatial Antenna Modulation (DSAM) combines the RF modulator and antenna functions, using spatial aspects of the antenna to modulate signals by switching the RF feed to different spatial points, eliminating the need for a separate modulator stage and reducing linearity requirements for power amplifiers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the RF modulator and antenna are treated as separate system elements with independent design, then the system modulates the RF carrier signal to form a composite signal, but power loss occurs in the modulation process requiring additional re-amplification
Solution Approach 1:
The patent merges the RF modulator and antenna into a single integrated structure where the antenna itself performs the modulation function. The antenna is designed with multiple feed points that can be selectively excited to directly modulate the RF carrier signal, eliminating the need for a separate modulator stage and the associated power losses.
Solution Approach 2:
The antenna structure is designed to serve multiple functions simultaneously: it acts as both the radiating element and the modulating device. By incorporating multiple feed points with different spatial characteristics, the antenna can perform signal radiation, modulation, and beamforming functions without requiring separate dedicated components for each function.
2Ease of operation
If a separate modulator stage is used to modulate the RF carrier signal, then the composite modulated signal is formed, but additional re-amplification is required which increases system power supply consumption
Solution Approach 1:
The modulator function is merged into the antenna structure itself. The antenna is designed with multiple feed points that can be selectively excited to directly modulate the RF carrier signal, eliminating the need for a separate modulator stage and the associated power losses.
Solution Approach 2:
The antenna structure performs self-modulation by utilizing its own spatial characteristics and multiple feed points. The selective excitation of different feed points directly imprints the modulation onto the RF carrier signal without requiring external modulating components, making the system more energy-efficient.
3Power
If the final amplification stage processes the composite modulated signal directly, then the signal is amplified to the desired transmit power level, but linearity performance requirements are imposed that reduce maximum output power
Solution Approach 1:
The modulation is performed preliminarily through the spatial excitation of antenna feed points before the signal reaches the power amplification stage. This preliminary modulation action through spatial selection simplifies the requirements for subsequent amplification, allowing the power amplifier to operate with relaxed linearity constraints while still achieving the desired transmit power levels.
Solution Approach 2:
The patent replaces the traditional electronic modulation mechanism (using separate modulator circuits) with a spatial modulation mechanism (using antenna feed point selection). This substitution fundamentally changes how modulation is achieved, moving it from the electrical domain to the spatial domain, which subsequently relaxes the linearity requirements on the power amplification stage.
Data Source
AI summary
A system and method for arbitrarily switching phase and amplitude at an antenna. A Direct Spatial Antenna Modulation (DSAM) system makes use of the spatial characteristics of a radiating antenna structure to directly alter a signal transmitted or received by the radiating structure. A data stream maps a carrier to different spatial points of excitation in the antenna structure, where each chosen configuration has different radiating characteristics including phase, amplitude, and polarization, which can be used represent data symbols. The spatial points of a radiating structure may be mapped directly to In-Phase and Quadrature components of the output using two spatial feedpoints and amplitude control to the feedpoints. This abstract is not to be considered limiting, since other embodiments may deviate from the features described in this Abstract.