Sparse Phased-Array-Fed Lens Antennas With Reduced Grating Lobes
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Solution Overview
Problem
Existing phased array antennas face challenges in minimizing grating lobes while maintaining effective signal transmission and reception, particularly when element spacing exceeds half the wavelength.
Innovation Solution
The proposed solution involves a sparse phased-array-fed lens (SPAFL) antenna system with elements spaced greater than half the wavelength, up to 1.0λ, using a reflector or lens such as a GRIN lens to minimize grating lobes and optimize beamforming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If antenna element spacing is increased beyond half the wavelength to reduce the number of elements, then device complexity and cost are reduced, but grating lobes are generated that degrade beamforming quality
Solution Approach 1:
A lens is introduced as an intermediary component between the sparsely-spaced antenna elements and the radiation space. The lens focuses and shapes the electromagnetic waves, enabling effective beamforming despite the large element spacing that would otherwise produce grating lobes. This mediator allows the system to achieve both reduced element count and maintained beamforming quality.
Solution Approach 2:
The patent changes the spacing parameter of antenna elements from the conventional sub-half-wavelength spacing to spacing greater than half the wavelength (up to 1.0λ or more). This parameter change reduces the number of elements required while the lens compensates for the resulting grating lobe effects, resolving the contradiction between element count and beamforming quality.
2Use of energy by moving object
If antenna element spacing exceeds half the wavelength, then the number of elements and power consumption are reduced, but grating lobes increase causing signal degradation
Solution Approach 1:
The lens serves as a mediator that suppresses the harmful grating lobes generated by sparsely-spaced elements. By positioning the lens at an appropriate distance from the antenna elements, it focuses the main beam while suppressing grating lobe radiation, enabling large element spacing without the usual penalty of grating lobe degradation.
Solution Approach 2:
The patent converts the potentially harmful grating lobe effect into a beneficial configuration by carefully selecting the lens position and parameters. The grating lobes that would normally degrade performance are transformed into additional beamforming control capabilities, allowing the system to achieve low power consumption through reduced element count while maintaining or even improving beamforming quality.
3Ease of manufacture
If sparse element spacing greater than half wavelength is used, then manufacturing cost and device complexity are reduced, but grating lobe suppression becomes more difficult
Solution Approach 1:
The lens acts as a manufacturing-enabling intermediary that allows sparsely-spaced elements to be used without sacrificing grating lobe suppression. Instead of requiring precise sub-half-wavelength spacing to avoid grating lobes, the lens provides the suppression function, greatly simplifying manufacturing while maintaining performance.
Solution Approach 2:
The patent segments the beamforming function between the antenna elements (which only need to provide broadside radiation) and the lens (which provides the precise focusing and grating lobe suppression). This segmentation allows the antenna elements to be sparsely and simply manufactured, while the lens handles the complex wave shaping required for grating lobe suppression.
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 configuration allows for high-quality beamforming with reduced grating lobes, lower sidelobes, and improved scan loss, while also reducing the number of antenna elements required, leading to lower power consumption and cost.
Implementation Method 1
a lens instead of a reflector may be used to direct and focus incoming or outgoing signals or beams
Implementation Method 2
the phased array 210 is being used to transmit signals. In particular, the phased array 210 is used to generate a directional signal that reflects off of reflector 205
Data Source
AI summary
An apparatus includes a plurality of antenna feed elements arranged in an array and a reflector or lens. The reflector or lens is configured to focus a first signal generated by the plurality of antenna feed elements or focus a second signal not generated by the plurality of antenna feed elements onto the plurality of antenna feed elements. The apparatus further includes a controller or processor configured to control the plurality of antenna feed elements to generate the first signal or receive the second signal. The first signal and the second signal have a nominal wavelength. The plurality of antenna feed elements are spaced from one another in the array at a distance greater than half of the nominal wavelength.