Loop Antenna Array With Notched Elements For Side Lobe Suppression
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Solution Overview
Problem
Conventional array antenna devices have limited control over radio wave radiation, leading to high side lobes and increased size, which can cause incorrect detection in radar systems and grating lobes, especially when arranged in a short-length configuration.
Innovation Solution
The array antenna device features a substrate with a strip conductor and loop elements having notches, connected by feeding elements that adjust coupling amounts to suppress side lobes and reduce size by using loop elements with a ½ wavelength arc length, allowing for phase excitation and reduced spacings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional array elements with sub-feeding strip lines and stubs are used, then the antenna can radiate radio waves, but the control range of radiation amount is limited (30%-40%) and side lobes cannot be suppressed
Solution Approach 1:
The patent changes the fundamental parameters of the antenna element by using loop elements with notches instead of conventional strip line configurations. The notch depth and position in the loop elements can be adjusted to control the radiation amount over a wide range (0-100%), enabling effective side lobe suppression through amplitude control of individual elements.
Solution Approach 2:
The patent introduces adjustable feeding elements that can dynamically control the coupling amount between the main feeding strip line and loop elements. This dynamic control capability allows the radiation amount of each array element to be independently adjusted, providing the versatility needed to suppress side lobes while maintaining main beam performance.
2Ease of operation
If conventional array elements are used, then the antenna can function, but the array element size is large causing device upsizing when arranged in short-length direction
Solution Approach 1:
The patent segments the conventional large array element into smaller components: loop elements with notches and separate feeding elements. This segmentation allows the elements to be arranged more compactly in the short-length direction of the main feeding strip line, reducing the overall device size while maintaining functionality.
Solution Approach 2:
The patent uses loop elements with arc lengths of ½ wavelength or more, utilizing the circular/loop geometry to achieve the required electrical length in a more compact physical footprint. This dimensional optimization allows elements to be packed more densely in the short-length direction without increasing spacing.
3Productivity
If larger spacings are used in short-length direction, then array elements can be arranged, but grating lobes occur easily and device size increases
Solution Approach 1:
The patent employs feeding elements with adjustable coupling amounts that can dynamically control the amplitude distribution among array elements. By optimizing the amplitude tapering through adjustable coupling, the patent can suppress grating lobes even when elements are arranged with smaller spacings in the short-length direction, increasing arrangement density while maintaining radiation pattern quality.
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 effectively suppresses side lobes and cross-polarization, enabling accurate detection and downsizing of the antenna device while maintaining high gain, even when arranged in a short-length configuration.
Implementation Method 1
a plurality of loop elements which are provided on a first surface of the substrate and are located along the strip conductor with a specified spacing from each other, each of the plurality of loop elements having a loop-shape with a notch
Implementation Method 2
a plurality of feeding elements connected to the strip conductor, each of the plurality of feeding elements having a shape extending along a portion of an outer edge of corresponding one of the plurality of loop elements
Data Source
AI summary
An array antenna device of this disclosure includes a substrate, a strip conductor with a linear-shape, which is provided on the substrate, and a power feeder that feeds power to the strip conductor, and a plurality of loop elements, a conductor plate, and a plurality of feeding elements. The plurality of loop elements are provided on a first surface of the substrate, and are located along the strip conductor with a specified spacing from each other. Each of the plurality of loop elements has a loop-shape with a notch. The plurality of feeding elements are connected to the strip conductor, and each has a shape extending along a portion of an outer edge of corresponding one of the plurality of loop elements. The conductor plate is provided on a second surface of the substrate.