Zero electromagnetic coupling of closely spaced identical helical resonators

Area of Science:

• Electromagnetics
• Metamaterials Science
• Resonator Physics

Background:

• Closely spaced elements in electromagnetic arrays exhibit significant inter-element coupling.
• This coupling negatively impacts the performance of metamaterials, filters, and phased arrays.
• Controlling electromagnetic coupling is crucial for advanced electromagnetic devices.

Purpose of the Study:

• To investigate and demonstrate near-zero electromagnetic coupling between identical helical microwave resonators.
• To explore the influence of specific geometric conditions on inter-element coupling.
• To analyze the behavior of infinite periodic chains of helical resonators.

Main Methods:

• Numerical simulations were employed to model electromagnetic coupling.
• Experimental validation was performed using precisely constructed helical resonators.
• 3D-printed molds and Field's metal were utilized for fabricating experimental samples.

Main Results:

• Near-zero electromagnetic coupling was achieved between helical resonators at highly sub-wavelength separations under specific geometric conditions.
• Precise and repeatable resonator construction was enabled by the fabrication method.
• Numerical analysis of infinite periodic chains showed control over propagating mode dispersion, including near-zero group velocity.

Conclusions:

• Specific geometric configurations can eliminate or minimize electromagnetic coupling between closely spaced helical resonators.
• This finding has significant implications for the design and performance enhancement of metamaterials, filters, and phased arrays.
• The ability to control coupling and dispersion in periodic structures opens avenues for novel electromagnetic wave manipulation.