Metamaterial leaky-wave antenna based on complementary split-ring resonators

These last decades have seen the emergence of the metamaterial concept. Metamaterial structures present physical properties that do not exist in nature. They are especially attractive in the area of microwave RF engineering. In 1968, Veselago proposed the idea of using simultaneous negative permeability and permittivity materials. This concept was then claried and consolidated in published works from 2000 concerning the topic of these left-handed cells, providing additional degrees of freedom for system designers. They have facilitated : a considerable decrease in the size of microwave components such as lters or couplers, an increase in system bandwidth, useful for ultra wide band applications, an easy insertion of electrical-tunable elements, these elements could in uence the physical properties of an antenna with a simple DC voltage applied to the circuit, amongst other things. The focus of this work is on one-dimensional leaky wave antennas (LWAs) using the metamaterial concept. These are wave-guiding structures from which electromagnetic waves leak, as they are guided along their length, in the form of coherent radiation. Using a simple feed for a LWA, this line facilitates full-space continuous scanning with respect to variation in operating frequency. The metamaterial concept selected in this thesis is the dual of a microstrip line, based on the complementary split ring resonator (CSRR), which is used to load the transmission line and hence permit a full-space continuous beam scanning with frequency. Full wave simulations and measurements in an anechoic chamber demonstrate a particular behavior: radiation seems to be equally split into two dierent directions resulting in two apparent beams in the plane of the substrate. Clearly, the radiation is not maximal in the broadside direction as predicted by the theory. The objective of this thesis is to understand the physical reasons of this behavior and the in uencing parameters of interest. Other resonant structures are also considered, that are similar to the CSRR structure and CSRR-loaded ferroeletric LWA controlled by DC voltage.(FSA 3) -- UCL, 201

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Investigation of metamaterial leaky wave antenna based on complementary split ring resonators

This paper aims at designing an RF tag planar antenna around 2.4 GHz enabling a frequency beam steering in the plane of the substrate. The structure is based on a leaky-wave antenna topology using a transmission line with series (capacitive) gaps and CSRRs periodically loading a host microstrip line. Its behaviour is first assessed by the array factor approach using simulated S-parameters that are validated by measurements. Full-wave simulations of radiation pattern with IE3D software show that radiation occurs mainly in the plane of the substrate and is tunable with frequency.Anglai

Substrate Edge Effects in Leaky Wave Antenna Based on Complementary Split Ring Resonators

This paper discusses radiation phenomena in a metamaterial transmission line based on series capacitive gaps and CSRRs periodically loading a host microstrip line and acting as a leaky-wave antenna. The analysis performed for different distances between CSRRs and the substrate edges shows that in narrow substrates destructive interference occurs between free-space leaky wave radiation and surface wave modes, reflected at substrate edges.Anglai

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