Design Of Metamaterials And Loading In Microstrip Antennas Based On Irregular Left-handed Cell Structures

The left-handed material is a kind of artificially synthesized new electromagnetic material.Compared with natural materials,it has many excellent properties and has been paid more and more attention by researchers.But most of the traditional design of the left-hand unit structure is relatively simple and has less adjustment parameters,so how to design a new type of irregular left-handed structure which can flexibly regulate the double negative band is necessary.This dissertation focuses on the serialized design of single-sided irregular left-hand unit structure,and generates more tunable parameters through different topology methods.In addition,the left-hand unit structure is loaded into the antenna through simulation,and the antenna performance is optimized in different ways.The specific research work is as follows:1.A series of researches on T-bar-symmetrical arc LH unit structure are proposed.And improvement of multiple passbands is carried out.Firstly,the T-rod-symmetrical arc left-hand unit structure is designed.It is composed of a broken arc and T-metal rod.The structure has a resonance frequency of 5.68 GHz and a double negative frequency of 5.52-5.82 GHz,Then,the effect of different deformations on the basic structure was analyzed by changing the radius of the lower half arc,increasing the number of arcuate branches and S-shaped arcs.Then the three T-ellipse-arc left-hand unit structure with different arrangement along the y-axis is designed.The first left-hand unit structure bandwidth is improved,and the second left-hand unit structure achieves dual-frequency and double-negative features.The third left hand cell structure forms two double negative bands and the bandwidth is extended.2.A double-hook-based LH unit structure series is proposed,and the topology is improved:Firstly,a double-hook type left-hand unit structure is designed.The structure has a resonant frequency of 4.50 GHz and a double negative frequency of 4.38 GHz to 4.82 GHz.Then,the basic structure was deformed to increase the number of arcuate branches and the S-shaped structure.The addition of arcuate nodes on the left and right sides allows for more flexible regulation of the double-negative frequency band;increasing the reverse-opening S-type structure enables dual-band left-handed performance.Finally,a double-hook umbrella-like asymmetric left-hand structure is designed,which achieves more adjustable parameters.The quality factor of the entire left-hand unit structure series is high,which means that the loss is low.3.Analysising antenna performance Loading the left-hand unit:First designing a fan-shaped broadband antenna,the working frequency band is from 2.07GHz to 8.90GHz.Then the left-hand structure is loaded on the left and right sides of the antenna,which expands the bandwidth of the antenna(increase 1.14 GHz).Then,the notch effect is achieved through the application of two different left-hand cell structures:firstly,two double-hook reversely spaced S-type left-hand structures are loaded on both sides of the antenna feed line,and traps are generated in three frequency bands;The layer etched the double-T rod-elliptic arc left-hand cell structure achieve the notch effect.A three-band antenna with three notches is obtained.After that,the T-bar-asymmetrical arc left-hand unit structure is loaded to the two sides of the monopole antenna by simulation,and the dual-frequency monopoles antenna with resonance frequency of 4.83 GHz(5G microwave intermediate frequency)and 5.84 GHz(WLAN high frequency)is obtained.Finally,the T-bar-arc branch left-hand unit structure is etched on the ground plane of the microstrip antenna by simulation,and the working frequencies is at 3.59 GHz and 4.84 GHz,and the two microwave mid-ranges(3.30 GHz-3.60 GHz)and 4.80GHz-5.00GHz)dual-frequency microstrip antenna at 5G.