Dual-Substrate EBG Device for High-Frequency Bandgap

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Solution Overview

Problem

Conventional Electromagnetic Bandgap (EBG) devices face challenges in manufacturing high upper bandgap frequencies and resonant frequencies, particularly in high-frequency applications, due to manufacturing process imprecision and cost considerations, making it difficult to achieve desired performance without using expensive and atypical processes.

Innovation Solution

The solution involves a dual-substrate EBG device structure with overlapping periodic lattices of conducting vias, where the second substrate's vias have a smaller diameter than the first substrate's vias, allowing for closer spacing and higher bandgap frequencies without interfering with coplanar waveguide inputs and outputs, and optionally incorporating defect resonators to achieve specific resonant frequencies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional single-substrate EBG devices are used, then manufacturing is simpler, but upper bandgap frequency and resonant frequency are limited below 65 GHz

Engineering Contradiction:
Improveupper bandgap frequency and resonant frequencyVSAvoiddevice structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The EBG device is divided into two separate substrates, each carrying a periodic lattice of conducting vias. The first substrate has vias with a first diameter, while the second substrate has vias with a second diameter that is smaller than the first diameter. This segmentation allows each substrate to be optimized independently for high-frequency performance while maintaining manufacturing feasibility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from a single-substrate two-dimensional structure to a multi-layer three-dimensional structure with two substrates positioned at different heights. The substrates are spaced apart vertically, with conducting vias extending through each substrate and making contact between layers, enabling higher bandgap frequencies unattainable in conventional planar configurations.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Manufacturing precision

If via spacing is reduced to increase bandgap frequency, then upper bandgap frequency increases, but coplanar waveguide inputs and outputs are interfered with

Engineering Contradiction:
Improveupper bandgap frequencyVSAvoidcoplanar waveguide input/output
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

By moving the periodic lattice structure to a second substrate positioned vertically above the first substrate, the invention separates the high-frequency bandgap function (requiring closely spaced vias) from the waveguide input/output interfaces. The vertical spacing between substrates allows the coplanar waveguides to operate on the first substrate without interference from the closely spaced vias on the second substrate, while still achieving high upper bandgap frequencies.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Manufacturing precision

If expensive atypical manufacturing processes are used, then high upper bandgap frequencies can be achieved, but manufacturing cost increases

Engineering Contradiction:
Improveupper bandgap frequencyVSAvoidmanufacturing cost
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

Dividing the device into two substrates allows each to be manufactured using standard, cost-effective processes. The conducting vias in each substrate can be formed using conventional via drilling and plating techniques, and the substrates can be assembled using standard bonding methods. This segmentation avoids the need for expensive atypical single-step manufacturing processes while achieving the required high-frequency performance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention uses parameter changes in the via diameters between substrates (first diameter on first substrate, smaller second diameter on second substrate) to optimize electromagnetic performance. This parameter variation allows achievement of upper bandgap frequencies greater than 65 GHz through geometric optimization rather than expensive manufacturing processes, maintaining cost-effectiveness while improving performance.

Inventive Principle:
Principle #35Parameter changes

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 enables EBG devices to achieve upper bandgap frequencies and resonant frequencies of greater than 65 GHz, surpassing conventional devices without requiring expensive manufacturing processes, while maintaining effective signal attenuation within the bandgap.

Implementation Method 1

A typical EBG device functions to block or suppress the propagation of electromagnetic radiation that falls within a certain defined frequency band known as a stopband or bandgap

Methodology Applied
Scientific EffectElectromagnetic bandgap:

Implementation Method 2

a defect resonator in an EBG device typically creates an area of resonance in the EBG device by localizing energy within the structure, allowing transmission of a narrow frequency within the stopband or bandgap

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP1942557B1High-frequency electromagnetic bandgap device and method for making same
Publication Date: 2019.05.22 DELPHI TECHNOLOGIES INC
  • EP1942557B1 patent drawingFigure 1A~1B
  • EP1942557B1 patent drawingFigure 1C~1D
  • EP1942557B1 patent drawingFigure 2

AI summary

A high-frequency Electromagnetic Bandgap (EBG) device (70,90), and a method (100) for making the device are provided. The device (70,90) includes a first substrate (72) including multiple conducting vias (74) forming a periodic lattice. The vias (74) ofthe first substrate (72) extend from the lower surface ofthe first substrate (72) to the upper surface of the first substrate (72). The device (70,90) also includes a second substrate (76) having multiple conducting vias (78) forming a periodic lattice. The vias (78) ofthe second substrate (76) extend from the lower surface of the second substrate (76) to the upper surface of the second substrate (76). The second substrate (76) is positioned adjacent to, and overlapping, the first substrate (72), such that the lower surface of the second substrate (76) is in contact with the upper surface of the first substrate (72), and such that a plurality of vias (78) of the second substrate (76) are in contact with a corresponding plurality of vias (74) of the first substrate (72).