Antenna Array Side Lobe Mitigation via Phase Differential
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Solution Overview
Problem
Conventional directional antenna systems, such as flat panel traveling-wave antenna arrays, suffer from significant side lobe levels due to constructive interference, leading to unintended reception of adjacent satellite signals during RF reception and interference with other RF signals during transmission, which hampers selective communication and distinguishes between transmitters.
Innovation Solution
The antenna array employs a phase differential between signals emitted by different antennae, achieved through varying physical characteristics such as emitter positions and dielectric properties, to induce a passive phase difference that facilitates destructive interference and mitigates side lobe formation, using a distribution of phase differences analogous to the 'Circle of Fifths' for optimal interference avoidance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If multiple identical waveguides are arranged in parallel to transmit signals, then the antenna array can provide directional transmission, but the side lobes constructively interfere and produce significant side lobe levels
Solution Approach 1:
The patent applies local quality by making each waveguide non-identical through variations in emitter positions and dielectric properties. Specifically, different waveguides have emitters at different locations and different dielectric materials or configurations, creating local differences that result in different phase characteristics for each waveguide's emitted signal. This local variation prevents uniform constructive interference of side lobes while maintaining the overall directional transmission function of the antenna array.
Solution Approach 2:
The patent implements asymmetry by deliberately introducing asymmetrical variations in the waveguide structures. The emitter positions are intentionally placed at different locations along different waveguides, and dielectric properties are varied asymmetrically across the array. These asymmetrical configurations ensure that each waveguide produces signals with unique phase profiles, preventing the symmetrical constructive interference that creates high side lobe levels in conventional identical-waveguide arrays.
2Ease of manufacture
If identical emitter positions and dielectric properties are used across all waveguides, then manufacturing is simplified, but phase differences between signals are insufficient to mitigate side lobe formation
Solution Approach 1:
The patent resolves this contradiction by applying local quality - making each waveguide slightly different in specific local characteristics (emitter positions and dielectric properties) while maintaining overall structural consistency. This approach balances manufacturing feasibility with performance requirements, as the variations can be introduced through controlled manufacturing processes rather than requiring complete redesign of each waveguide.
Solution Approach 2:
The patent employs parameter changes by systematically varying key parameters of the waveguides, specifically emitter positions and dielectric properties. These parameter variations are controlled and deliberate, creating the necessary phase differences to mitigate side lobes while maintaining manufacturability. The changes are implemented in a way that allows for practical manufacturing, such as using standard dielectric materials with different properties or positioning emitters at predetermined locations.
3Stability of the object's composition
If phase differences between signals are integer multiples of each other, then signal coherence is maintained, but constructive interference increases side lobe levels
Solution Approach 1:
The patent addresses this contradiction by introducing asymmetry in the phase relationships between signals from different waveguides. By varying emitter positions and dielectric properties, the patent ensures that phase differences are not integer multiples of each other, thereby preventing the periodic constructive interference that creates high side lobes. This asymmetrical phase distribution maintains signal coherence for the main beam while reducing side lobe interference.
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 reduces side lobe levels by ensuring that phase differences between signals are not integer multiples of each other, thereby minimizing constructive interference and enhancing directional transmission characteristics.
Implementation Method 1
an antenna array includes a first antenna and a second antenna, where a first signal is provided at a first input of the first antenna while a second signal is provided at a second input of the second antenna. As the first signal and the second signal variously propagate away from the first input and the second input, respectively, the first antenna and the second antenna passively induce a change in a phase differential between the first signal and the second signal.
Implementation Method 2
a phase difference between respective portions of the first signal and the second signal may be emitted from the first antenna and second antenna respectively, wherein a passively-induced phase difference between these portions facilitates destructive interference of the first signal and the second signal with each other
Data Source
AI summary
Techniques and mechanisms to transmit signals with an antenna array. In an embodiment, a first signal is received at a first input of the first antenna while a second signal is received at a second input of the second antenna. A difference in phase differentials—the phase differentials each between the first signal and the second signal—results from propagation of the first signal and the second signal in the antenna array and from a difference between respective configurations of the first antenna and the second antenna. Each of the first antenna and the second antenna has respective emitters distributed along the length thereof. In another embodiment, the first antenna and the second antenna have different respective dielectric structures or different respective distributions of emitters.