EMNZ Metamaterial Waveguide with Tunable Graphene Impedance

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Solution Overview

Problem

Epsilon-and-mu-near-zero (EMNZ) metamaterials exhibit near-zero characteristics only in a limited frequency range, limiting their applications in microwave and antenna engineering, and lack an adjustable cutoff frequency.

Innovation Solution

An EMNZ metamaterial with a waveguide and a tunable impedance surface, including a graphene monolayer, is designed to adjust the cutoff frequency by varying the chemical potential of the graphene monolayer, allowing near-zero permittivity and permeability across a wide frequency range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional EMNZ metamaterials are used, then near-zero characteristics are achieved, but the bandwidth is very limited and the cutoff frequency is not adjustable

Engineering Contradiction:

Improvefrequency rangeVSAvoidstructure complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies the dynamics principle by making the cutoff frequency adjustable through external control. The waveguide structure incorporates a movable shorting piston that can be positioned at different locations along the waveguide, thereby dynamically adjusting the cutoff frequency. This allows the EMNZ metamaterial to adapt to different frequency ranges while maintaining near-zero characteristics, resolving the contradiction between limited bandwidth and structural complexity.

Inventive Principle:

Principle #15Dynamics

2Adaptability or versatility

If the waveguide length is reduced to l≤0.1λ, then the near-zero characteristics are maintained across broader frequency ranges, but the waveguide becomes extremely short

Engineering Contradiction:

Improvefrequency rangeVSAvoidwaveguide length

Core Design Contradiction:

Adaptability or versatilityVSLength of moving object

Solution Approach 1:

The patent applies parameter changes by systematically optimizing the waveguide dimensions to achieve l≤0.1λ while incorporating adjustable parameters such as the shorting piston position and waveguide cross-sectional dimensions. By changing these parameters, the system maintains near-zero characteristics across broader frequency ranges despite the extremely short length, resolving the contradiction between frequency range adaptability and physical length.

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

The solution enables EMNZ metamaterials to maintain near-zero characteristics across a broader frequency range, enhancing their applicability in microwave and antenna engineering by making the cutoff frequency adjustable.

Implementation Method 1

adjust the cutoff frequency by varying the chemical potential of the graphene monolayer

Methodology Applied

Scientific EffectChemical potential tuning:

Implementation Method 2

INZ metamaterials may transmit waves without altering phase of waves. As a result, a transient wave phase may remain constant when the transient wave travels in an INZ metamaterial.

Methodology Applied

Scientific EffectNear-zero refractive index effect: Negative Refraction

Implementation Method 3

epsilon-and-mu-near-zero (EMNZ) metamaterials with near-zero permittivity and permeability coefficients

Methodology Applied

Scientific EffectNear-zero permittivity and permeability: Dielectric Permittivity

Data Source

PatentUS11502383B2EMNZ metamaterial configured into a waveguide having a length that is less than or equal to 0.1 of a wavelength

Publication Date: 2022.11.15 AMIRKABIR UNIVERSITY OF TECHNOLOGY

AI summary

An epsilon-and-mu-near-zero (EMNZ) metamaterial. The EMNZ metamaterial includes a waveguide. A length l of the waveguide satisfies a length condition according to l≤0.1λ, where λ is an operating wavelength of the EMNZ metamaterial. The EMNZ metamaterial further includes a magneto-dielectric material deposited on a lower wall of the waveguide. The waveguide includes an impedance surface placed on the magneto-dielectric material.