Embedded Interdigital Defected Ground Structure for Harmonic Suppression
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Solution Overview
Problem
Modern communications systems face challenges in suppressing out-band signals effectively due to the large size and limited harmonic suppression capabilities of existing filters, which are not adequately addressed by current technologies.
Innovation Solution
The integration of an embedded interdigital structure within a defected ground structure in resonant units and filters enhances harmonic suppression capabilities while reducing the overall size, achieving ultra-wide out-band harmonic suppression through the introduction of multiple resonant points and a slow-wave effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional filters are used to suppress high-order harmonic waves, then harmonic suppression capability is improved, but the filter area becomes large
Solution Approach 1:
The patent embeds an interdigital structure within the defected ground structure, creating a nested configuration where one resonant structure is placed inside another. This nested arrangement allows multiple resonant modes to coexist in a compact space, achieving wide harmonic suppression without increasing the overall filter area
Solution Approach 2:
The patent utilizes the vertical dimension by embedding the interdigital structure within the planar DGS, transitioning from a two-dimensional layout to a three-dimensional nested configuration. This dimensional change enables compact integration of multiple resonant elements, reducing the required filter area while maintaining suppression capability
2Reliability
If stepped impedance resonator is used to generate wide stopband, then out-band suppression is improved, but the filter area increases
Solution Approach 1:
The patent segments the ground structure into a defected ground structure with embedded interdigital elements, creating multiple independent resonant sections. Each segment contributes to the overall stopband, and their combined effect achieves wide harmonic suppression in a compact configuration
Solution Approach 2:
The patent creates a composite resonant structure by combining DGS and interdigital structures, leveraging the complementary characteristics of both configurations. This composite approach enables wide stopband generation with reduced area compared to traditional single-structure filters
3Reliability
If transmission zero is added to suppress harmonic waves, then harmonic suppression capability is improved, but device complexity increases
Solution Approach 1:
The patent merges the functions of multiple resonant structures into a single integrated DGS with embedded interdigital elements. This unified structure simultaneously provides multiple transmission zeros and resonant frequencies, achieving harmonic suppression without requiring separate components or complex interconnections
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 approach improves the filter's ability to suppress high-order harmonic waves, achieves a wide stopband, and miniaturizes the filter, thereby enhancing out-band suppression capabilities while reducing the filter's area and costs.
Implementation Method 1
each embedded interdigital structure in the at least one embedded interdigital structure is used to introduce a resonant frequency of the resonant unit
Data Source
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AI summary
A resonant unit and a filter are provided. The resonant unit includes: a dielectric substrate; a metal microstrip disposed on a plane of the dielectric substrate, where the metal microstrip is used as a signal input/output port; and a defected ground structure disposed on another plane opposite to the plane of the dielectric substrate, where the defected ground structure includes a ground loop and an interdigital structure located inside the ground loop, the interdigital structure includes multiple fingers, and the ground loop or at least one finger in the interdigital structure includes at least one embedded interdigital structure. Harmonic suppression capabilities of the resonant unit and the filter can be improved, and an area can be reduced.