Super Directive Antenna Phase Shifter Design
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Solution Overview
Problem
Electrically small antennas face limitations in radiation efficiency and bandwidth due to their small size, and achieving super-directivity is impractical due to mutual coupling and fabrication tolerances, while biological systems like insects demonstrate enhanced directional hearing capabilities that are not directly translatable to higher gain or directivity in antenna arrays.
Innovation Solution
A receiver system comprising a plurality of antennas and a signal processing circuit with a phase shifter that applies a phase shift based on the angle of incidence, effectively increasing the phase difference between signals received by closely spaced antennas to enhance directional sensitivity without increasing physical aperture size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the electrical dimensions of an antenna are decreased, then the antenna size is reduced, but the radiation efficiency and bandwidth also decrease
Solution Approach 1:
The patent transitions from spatial dimension to temporal dimension by using time-varying excitation coefficients that oscillate rapidly. This allows small antenna arrays to achieve super-directivity through temporal modulation rather than requiring large spatial apertures, thereby maintaining small physical size while improving radiation efficiency and bandwidth through dynamic control
2Volume of moving object
If the overall electrical dimensions of the antenna array decrease, then the antenna array size is reduced, but the excitation coefficients become significantly oscillatory and widely varying
Solution Approach 1:
The patent employs dynamic time-varying excitation coefficients that are continuously modulated rather than static fixed values. This dynamic approach allows the system to achieve super-directivity with relaxed tolerance requirements, as the temporal variation compensates for manufacturing imperfections and reduces sensitivity to element position errors
3Measurement precision
If the angular sensitivity of the antenna increases, then the directional resolution is improved, but the output signal to noise ratio decreases
Solution Approach 1:
The patent changes the temporal parameter of excitation coefficients, making them time-varying with specific oscillation patterns. This parameter modification allows the system to enhance angular sensitivity through temporal filtering effects while maintaining adequate signal-to-noise ratio by optimizing the time-varying characteristics to constructively combine signals from all array elements
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 system achieves improved directional resolution and sensitivity equivalent to larger aperture arrays, maintaining or improving angular sensitivity without increasing noise ratio, thus overcoming the limitations of small antenna arrays.
Implementation Method 1
The signal processing circuit includes a phase shifter configured to apply a phase shift to the received second signal. The phase shift applied by the phase shifter is a function of an angle of incidence of the second signal measured relative to a boresight direction of the plurality of antennas.
Data Source
AI summary
An electrically small receiver system is provided. The receiver system includes a plurality of antennas and a signal processing circuit. The plurality of antennas includes a first antenna configured to receive a first signal and a second antenna configured to receive a second signal. The signal processing circuit includes a phase shifter configured to apply a phase shift to the received second signal. The phase shift applied by the phase shifter is a function of an angle of incidence of the second signal measured relative to a boresight direction of the plurality of antennas. The signal processing circuit is configured to form an output signal that is a combination of the received first signal and the phase shifted second signal.