Single Notch Filter Using Fractal Defected Ground for UWB Applications

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Solution Overview

Problem

Conventional ultra-wideband (UWB) filter designs using multiple cascades result in larger system sizes, higher design costs, and efficiency issues due to part mismatching, while lacking in notch width variation and integration capabilities.

Innovation Solution

A single notch filter design incorporating a dielectric layer with a metal microstrip patch and a coplanar waveguide plate featuring a fractal defected ground body, allowing for compact structure and efficient notch filtering without the need for multiple cascades, achieved through spatial-to-electromagnetic characteristic conversion using fractal structures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple cascade filters are used to achieve UWB filtering, then the filtering performance is improved, but the system volume increases and design cost increases

Engineering Contradiction:

Improvefiltering performanceVSAvoidsystem volume

Core Design Contradiction:

ReliabilityVSVolume of stationary object

Solution Approach 1:

The patent merges multiple cascade filter functions into a single integrated filter structure using fractal defected ground structures. Instead of using separate cascade filters connected in series, the invention combines the filtering functionality into one compact unit that achieves the same UWB filtering performance with reduced volume.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The fractal defected ground structure employs a nested geometry where smaller fractal patterns are embedded within larger ones, allowing multiple filtering functions to be contained within a single compact structure. This nesting approach enables the filter to achieve complex multi-frequency rejection capabilities without requiring multiple separate filter components.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Reliability

If multiple cascade filters are used to achieve UWB filtering, then the filtering performance is improved, but the design cost increases

Engineering Contradiction:

Improvefiltering performanceVSAvoiddesign cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The single filter structure is designed to perform multiple filtering functions simultaneously across different frequency bands. The fractal defected ground structure provides universal filtering capability that replaces what would traditionally require multiple specialized filters, thereby reducing overall design complexity and cost.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Device complexity

If traditional notch filter design is used, then the filter structure is simple, but the notch width variation and expansion capability are limited

Engineering Contradiction:

Improvefilter structureVSAvoidnotch width variation range

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent utilizes parameter changes in the fractal defected ground structure geometry to control and adjust the notch width and frequency characteristics. By modifying geometric parameters such as fractal iteration depth, segment dimensions, and spacing, the filter can dynamically adjust its notch width and frequency response without changing the overall structure type.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The filter design incorporates adjustable and reconfigurable elements that allow dynamic modification of the notch characteristics. The fractal structure can be tuned to provide variable notch widths and frequency positions, enabling the filter to adapt to different application requirements while maintaining a relatively simple base structure.

Inventive Principle:

Principle #15Dynamics

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 solution provides a compact, high-performance UWB filter with expanded notch width and frequency variation range, addressing the limitations of conventional designs by reducing filter volume and improving system efficiency.

Implementation Method 1

the coplanar waveguide plate comprises a fractal defected ground body coupled with the metal microstrip patch

Methodology Applied

Scientific EffectFractal geometry: Fractal Forms

Implementation Method 2

forming two intersecting resonance frequency points to implement a wide notch according to a coupling and frequency shift relationship

Methodology Applied

Scientific EffectResonance: Resonance

Implementation Method 3

a dielectric layer having a first surface and a second surface

Methodology Applied

Scientific EffectDielectric properties: Dielectric

Implementation Method 4

forming two intersecting resonance frequency points to implement a wide notch according to a coupling and frequency shift relationship

Methodology Applied

Scientific EffectElectromagnetic resonance: Resonance

Data Source

PatentUS9997817B2Filter and electronic device

Publication Date: 2018.06.12 LENOVO (BEIJING) LTD

AI summary

Disclosed is a single notch filter, comprising a dielectric layer, a first metal layer and a second metal layer, wherein the first metal layer and the second metal layer are arranged onto two opposite surfaces of the dielectric layer, the first metal layer comprises a metal microstrip patch, the second metal layer comprises a coplanar waveguide plate and a metal grounding plate, and a fractal defected ground body of the coplanar waveguide plate is coupled with the metal microstrip patch based on the dielectric layer. Other embodiments are described and claimed.