Traveling-Wave Antenna Phase Diversity Feed for Grating Lobe Suppression
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Solution Overview
Problem
Traveling-wave antenna arrays face challenges in suppressing grating lobes due to restricted phase range and linked phase-amplitude characteristics, which can limit efficiency and increase costs, especially in applications requiring beamforming and steered beams.
Innovation Solution
The introduction of a phase diversity feed system that provides phase diverse input to adjacent traveling-wave antennas, allowing for phase offset between elements to suppress grating lobe formation by interfering individual output patterns and optimizing radiation patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If high dielectrics and dense element spacing are used to suppress grating lobes, then grating lobe suppression is improved, but efficiency decreases and system costs increase
Solution Approach 1:
The patent changes the phase parameter of the input signal to each antenna element, introducing phase diversity (e.g., 0, 2π/3, 4π/3 radians) to break the periodicity that causes grating lobes. This allows suppression of grating lobes without requiring high dielectrics or dense spacing, thereby maintaining system efficiency.
2Object-generated harmful factors
If high dielectrics and dense element spacing are used to suppress grating lobes, then grating lobe suppression is improved, but system costs increase
Solution Approach 1:
The patent modifies the phase parameter of the excitation signal rather than changing physical structural parameters like dielectric constants or element spacing. This approach suppresses grating lobes through signal processing rather than hardware modifications, reducing system complexity and cost.
3Object-generated harmful factors
If phase diverse input is provided to adjacent antennas, then grating lobes are suppressed, but device complexity increases
Solution Approach 1:
The patent divides the single feed structure into multiple independent feed points, each providing a different fixed phase shift. This segmentation allows phase diversity to be achieved through simple structural modification rather than complex active phase control systems.
Solution Approach 2:
Instead of using a single feed with active phase control (complex), the patent uses multiple feeds with fixed phase differences (simple). This inverts the approach from active control to passive structural design, reducing complexity.
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
This approach effectively suppresses grating lobes across various frequencies and beam steering directions, enhancing the efficiency and cost-effectiveness of traveling-wave antenna systems by eliminating unwanted lobes in the output beam pattern.
Implementation Method 1
allowing for phase offset between elements to suppress grating lobe formation by interfering individual output patterns
Data Source
AI summary
An apparatus includes a traveling-wave antenna array comprising a plurality of adjacent metamaterial surface antennas comprising a waveguide or a cavity, each adjacent metamaterial surface antenna comprising an array of metamaterial radiators coupled to a surface of the waveguide or the cavity, each metamaterial radiator comprising an individually addressable tunable component that can be tuned over a spectral bandwidth to generate different radiation patterns. The apparatus further includes a phase diversity feed coupled to the traveling-wave antenna array and configured to provide adjustable phase diverse input to two or more of the plurality of adjacent metamaterial surface antennas, the phase diverse input comprising a first phase for a first traveling-wave antenna and a second phase for a second traveling-wave antenna, the first phase being different from the second phase, wherein the phase diverse input is-selected to suppress grating lobes for a directed beam pattern selected for transmission.