Planar EBG Slot Structure for Adjacent Antenna Decoupling
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Solution Overview
Problem
The high fabrication cost of metallic vias in three-dimensional electromagnetic band-gap (EBG) structures for reducing coupling between adjacent RF antennas, which increases the cost of preventing electromagnetic wave coupling within specific frequency bands.
Innovation Solution
A two-dimensional EBG structure with H-shaped or L-shaped slots etched in the top conductive layer of an antenna substrate, forming a periodic pattern between adjacent antennas, which blocks surface waves without requiring additional fabrication steps or modifying the underlying substrate, thus reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a three-dimensional mushroom-like EBG structure with metallic vias is used, then electromagnetic wave blocking performance is improved, but fabrication cost increases significantly
Solution Approach 1:
The patent extracts the essential EBG functionality from the complex 3D mushroom structure with metallic vias and implements it using only planar conductive patterns on the PCB surface. This removes the expensive via fabrication step while maintaining the electromagnetic wave blocking capability through carefully designed conductive trace geometries that create the necessary current paths and electromagnetic coupling effects.
Solution Approach 2:
The patent transitions from a three-dimensional EBG structure to a two-dimensional planar implementation. By using conductive traces and patterns on the PCB surface rather than vertical via structures, the design achieves EBG functionality in a planar configuration that integrates seamlessly with standard PCB fabrication processes, eliminating the need for additional via drilling and plating operations.
2Reliability
If metallic vias are fabricated in large numbers, then EBG structure performance is achieved, but fabrication complexity and cost increase
Solution Approach 1:
The patent merges the EBG structure fabrication with the existing PCB trace patterning process. The conductive patterns that form the EBG structures are created using the same photolithography and etching steps used for other circuit traces on the board, consolidating multiple fabrication operations into a single integrated process flow that requires no additional equipment or process steps.
Solution Approach 2:
The conductive patterns serve dual functions: they form the EBG structures for electromagnetic wave blocking and simultaneously act as signal traces or ground connections for the antenna circuitry. This multi-functionality eliminates the need for separate via structures that would otherwise be required to provide both structural support and electrical connectivity.
3Ease of manufacture
If a planar EBG structure is used, then fabrication cost is reduced, but electromagnetic wave blocking effectiveness may be compromised
Solution Approach 1:
The patent applies local quality by varying the conductive trace geometry, width, and spacing in different regions of the EBG structure to optimize electromagnetic performance. The trace patterns are specifically designed with certain dimensions and configurations at critical locations to enhance current distribution and electromagnetic coupling, ensuring effective wave blocking despite the planar configuration.
Solution Approach 2:
The EBG structure employs periodic conductive patterns arranged in repeating units across the PCB surface. This periodic arrangement creates consistent electromagnetic coupling and current distribution characteristics that effectively block surface waves across the desired frequency range, leveraging the periodic nature of the structure to achieve broadband suppression without requiring complex 3D geometries.
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
The 2D EBG structure effectively decouples adjacent antennas within the E-band frequency range, improving signal-to-noise ratio and reducing noise floor in radar sensing and MIMO systems, while maintaining low fabrication costs by integrating with existing antenna fabrication processes.
Implementation Method 1
A periodic array of two-dimensional electromagnetic band-gap (EBG) structures are also fabricated in the top conductive layer. The periodic array of 2D EBG structures is located between the first E-band antenna and the second E-band antenna, wherein each EBG structure includes a plurality of slots formed in the top conductive layer, wherein the periodic array of 2D EBG structures blocks surface waves in the E-band frequency range.
Data Source
Figure 1A
Figure 1B~1C
Figure 2A~2B
AI summary
An electromagnetic band-gap (EBG) structure includes an antenna substrate layer and a first conductive region. The antenna substrate includes a first planar surface and a second planar surface. The first conductive region is located on the first planar surface of the antenna substrate. The first conductive layer includes a plurality of H-shaped slots formed within an interior of the first conductive layer. Each of the H-shaped slots in the first conductive layer exposes the first planar surface of the antenna substrate layer. The EBG structure is utilized in a periodic pattern between adjacent antennas.