"Cut wires grating – single longitudinal wire" planar metastructure to achieve microwave magnetic resonance in a single wire

Г А Крафтмахер ,В С Бутылкин

doi:10.7716/aem.v1i2.14

Г А Крафтмахер , В С Бутылкин

Open Access

https://doi.org/10.7716/aem.v1i2.14

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Abstract

Here we present metastructures containing cut-wire grating and a single longitudinal cut-wire orthogonal to grating’s wires. Experimental investigations at microwaves show these structures can provide strong magnetic resonant response of a single nonmagnetic cut-wire in dependence on configuration and sizes in the case when metastructures are oriented along the direction of wave propagation and cut-wires of grating are parallel to the electric field of a plane electromagnetic wave. It is suggested a concept of magnetic response based on antiparallel resonant currents excited by magnetic field of surface polaritons in many spatial LC-circuits created from cut-wire pairs of a grating and section of longitudinal cut-wire. Three separately observed resonant effects connected with grating, LC-circuits and with longitudinal cut-wire have been identified applying measurements in waveguides, cutoff waveguides and free space. To tune and mark resonance split cut-wires are loaded with varactor diodes.

Highlights

We kno w, at microwaves metamaterals with cond uctive nonmagnetic chiral i nclusions, c an possess a n e ffective magnetic p ermeability, which depends on the orien tation o f the in clusions with resp ect to th e m agnetic field h of t he incident el ectromagnetic wa ve
We suggest and verify a concept of magnetically-induced response based on possibility of resonant currents induction by magnetic field of s urface polaritons i n m any spatial LC-circuits fo rmed by Grating’s cu t-wire lp pairs an d section s of th e l ongitudinal cut-wire lm
We presen t resu lts of in vestigation of m etastructure “Grating - sing le lo ngitudinal cu t-wire” (Fig.1a), lik e [4 ], placed along propagation direction of electromagnetic wave and engineered to have magnetic resonance properties using only c ut-wires, lp an d lm are lengths o f gr ating’s wi re and longitudinal cu t-wire, s – di stance between Grating lp a nd single wire lm Grating (w ires lp are parallel to the E-field) exhibits a r esonance r esponse, wh ich is man ifested by resonance I of the electric-type an d cha racterized by a resonance dependence of the transmission coefficient with a minimum at a cert ain frequency de pendent o n t he wi re lp length

Summary

Introduction

At microwaves metamaterals with cond uctive nonmagnetic chiral i nclusions, c an possess a n e ffective magnetic p ermeability, which depends on the orien tation o f the in clusions with resp ect to th e m agnetic field h of t he incident el ectromagnetic wa ve. W e have u sed a standar d waveguide (23x10 mm ) an d a below-cutoff rectan gular sectio n (8x10mm) to measure transmission in frequency range 8-12 GHz. To prepare below-cuto ff rectangular section a fragment o f th e m ain WG (of th e length L= 25mm) is divided int o t hree se ctions by m etal spacers parallel to t he direction of wave propagation. T he m agnetic ex citation is characterized by the prese nce of s uper-forbidden ba nd below t he MR In t he case of electric e xcitation (electrictype resonance, ER), the transparency band in cutoff WG is observed below the ER frequency. “Grating - single lon gitudinal cu t-wire” metastructure (a) and its equivalent electric diagram (b)

Experimental verification

Grating lp

A E k h s

Split longitudinal cut-wire and parallel cut-wire loaded with varactor diodes

Discussion

Conclusions