Patch Antenna EBG Absent Region Beam Width
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Solution Overview
Problem
Existing patch antenna designs face a trade-off between suppressing surface current-induced directivity disturbances and maintaining a wide beam width, as methods to inhibit surface current transmission often result in reduced beam width, limiting the communicable range.
Innovation Solution
The antenna apparatus features a dielectric substrate with a ground plane and patch radiating elements, where conductive structures with varying absent distances around the patch radiating element are arranged to form a structure absent region, allowing for controlled surface current transmission and dispersion of radiation positions, thereby maintaining beam width while suppressing directivity disturbances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If EBGs are arranged on the overall surface surrounding the patch radiating element to suppress surface current transmission, then directivity disturbance is suppressed, but beam width decreases
Solution Approach 1:
The patent applies local quality by creating an EBG-free region (structure absent region) with a specific aspect ratio (width longer than length) in the peripheral area surrounding the patch radiating element. This localized modification allows surface current to transmit along the longer width direction while being suppressed in other directions, thereby maintaining beam width in the width direction while still suppressing directivity disturbance through selective EBG placement in other regions.
2Reliability
If EBGs are arranged on the overall surface surrounding the patch radiating element to suppress surface current transmission, then surface current transmission is suppressed, but ground of the patch antenna is substantially decreased
Solution Approach 1:
The patent removes EBG structures from the peripheral area to create an EBG-free region, thereby preserving the ground area in that region. The ground plate extends continuously into this EBG-free region without interruption from EBG structures, maintaining a larger effective ground area that supports the patch antenna's performance while still achieving directivity control through the aspect ratio effect.
3Ease of manufacture
If conductor portion is formed on the substrate front surface to reach the substrate end portions, then surface current flows to the conductor portion causing emission from substrate end portions, but this emission is unnecessary and disturbs directivity
Solution Approach 1:
The patent creates a differentiated structure where the peripheral area surrounding the patch radiating element has no EBG structures (EBG-free region), allowing surface current to flow freely in this region and reach the substrate end portions. This localized absence of EBGs in the peripheral area enables controlled surface current transmission that maintains beam width while the overall EBG structure in other regions still suppresses directivity disturbance.
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 widens the beam width by allowing longer surface current transmission in certain areas while dispersing radiation positions, thus retaining the desired beam width and suppressing directivity disturbances, enhancing the antenna's performance.
Implementation Method 1
This configuration composed of the conductive patch and the conductive via has a band gap (electromagnetic band gap) that inhibits the transmission of surface current through the ground plate at a certain frequency.
Data Source
AI summary
An antenna apparatus includes a dielectric substrate, a ground plate, a patch antenna provided with a patch radiating element, and a plurality of EBGs (Electromagnetic Band Gaps). The EBGs are composed of patch-shaped patterns formed on a surface of the substrate and connecting conductors electrically connecting the patch-shaped patterns and the ground plate. Each EBG is arranged to provide an EBG absent region having no EBG on the surface of the substrate. The patch radiating element is arranged within the EBG absent region. The EBG absent region is formed such that distances (absent distances) in a dominant polarized wave direction changes into a plurality of types depending on the position on a vertical patch line, where the distances range, to the boundary of the region, from an arbitrary position on the virtual patch line which is perpendicular to the dominant polarized wave direction of the patch antenna.