Vojislav Milosevic

Enhanced Modelling of Split-Ring Resonators Couplings in Printed Circuits

An enhanced equivalent circuit approach for the magnetic/electric interaction of single split-ring resonators (SRRs) with printed lines is presented in this paper. A very simple and efficient lumped-element network is proposed to model the behavior of metamaterial-based printed lines over a wide frequency band. The same circuit topology can be used for the single- and two-mirrored SRRs loaded microstrip line. The corresponding circuit parameters are obtained from the multiconductor transmission line theory as well as from closed-form expressions that make use of just the resonance frequency and minimum of the reflection coefficient (which should be previously extracted from experiments or full-wave simulations). The comparison of our equivalent circuit results with measurements and full-wave simulations has shown a very good agreement in a considerably wider frequency band than other previously proposed simple equivalent circuits.

Effective Electromagnetic Parameters of Metamaterial Transmission Line Loaded With Asymmetric Unit Cells

In this paper, we propose the generalized extraction procedure for retrieval of the effective constitutive parameters for a metamaterial transmission line loaded with asymmetric unit cells. The asymmetric unit cell is replaced with a transmission line immersed in equivalent bianisotropic medium described by effective parameters ε, μ, and Zc, and bianisotropic parameters u and η. The proposed retrieval procedure is applied to novel dual-band unit cells and compared with the standard Nicolson-Ross-Weir (NRW) method that is originally developed for the symmetric unit cell and then extended to the asymmetric one using the averaged value of reflection coefficients. It has been shown that, in case of pronounced asymmetry, the NRW method gives only the exact value of refraction, but effective permittivity and permeability are considerably different from the exact values since they are calculated by means of the approximate value of characteristic impedance.

Multiband delay lines with reconfigurable split-ring resonators

In this paper we proposed the novel multiband unit cell which consists of two types of split-ring resonators coupled to microstrip line: the broadiside coupled and the single split-ring resonator. Novel unit cell exhibits two left-handed bands that can be shifted by twisting split rings for certain angle or by changing their lengths. This unit cell is suitable for design of multiband frequency scanning antennas since can provide phase shift of 70 degrees per 100MHz of frequency shift.

EIT-like response in asymmetrically coupled split ring resonators

In this paper we demonstrate electromagnetically induced transparency achieved in metamaterials in which electromagnetic waves propagate along transmission line interacting with broadside coupled split-ring resonators. We introduce for the first time the EIT metamaterial excited with guided waves that exhibit a very low insertion loss followed with a large group index of refraction greater than 200 and large enhancement in group delay, enabling a significant slowdown of waves. We also demonstrate a precise control of the EIT response by moving the gaps in split-ring resonators.

Key millimeter wave technologies for 5G

Overview of the drivers and key enabling technologies for 5G mm-wave wireless communication systems will be given. Innovative mm-wave antenna designs, such as holographic antennas and metamaterial flat lens antennas will be presented.

Tuning EIT-like response in cross coupled SRRs

In this paper we present mimicking of the electromagnetically induced transparency (EIT) effect, obtained in metamaterial transmission line loaded with two cross coupled SRRs placed at the opposite sides of the line. The increased group delay between 2ns and 3ns is observed in the EIT-like transmission band. We demonstrate possibility of tuning the EIT-like frequency in the range of 15% by shifting the vertical gaps far from the line and to the line. That is followed by the change of the EIT-like magnitude in the range ±1.2dB in respect to the basic case. If changing the position of horizontal gaps to the left and to the right, the EIT-like frequency changes in the range of 13.7%, but is followed with great change of the transmission and reflection coefficients, so that way of tuning can be used to switch ON/OFF the EIT-like response.