Design Of Multiband And Miniaturized Microstrip Antenna Based On CRLH-TL

The popularity of intelligent portable devices and the rapid change of mobile terminal business have affected the social production and life mode.While supporting a variety of communication protocols,mobile terminal devices inevitably involve the broadband and multiband of antennas.The application of traditional microstrip antenna is quite mature,but the more integrated frequency band,the larger the size and the more complex the structure.The composite right/left-handed transmission line(CRLH-TL)structure in the form of a left-handed material microstrip can generate resonant modes of negative,zeroth,and positive,and its zeroth-order resonant(ZOR)mode is independent of physical size and only related to reactance parameters,which has become the focus of antenna miniaturization research.Based on CRLH-TL theory and ZOR theory,this paper aims to extend the antenna bandwidth and increase the resonant frequency band and three miniaturized antennas capable of supporting multiple communication protocols are designed.Firstly,a novel ACPW-fed quad-band hybrid antenna based on CRLH-TL is proposed.The design focuses on optimizing the combination of the two types of antennas to extend the antenna bandwidth.The ZOR mode can solve the limitation that low-frequency antennas are dependent on physical size and contribute to the miniaturization of antennas,while the monopole mode can be used to make up for the shortcomings of insufficient bandwidth of ZOR mode.Both simulation and measurement demonstrate that the antenna fully covers the working frequency band of 1.575GHz GPS,2.4/5.2/5.8GHz WLAN and 2.5/3.5/5.5GHz WiMAX,and has good radiation patterns.Then,for the upcoming 5G technology,a smart phone antenna for the IMT-2020(5G)of intermediate spectrum(3300-3600MHz,4800-5000 MHz)is proposed.The antenna combines a slot monopole antenna with a dual ZOR antenna through coexistence of multiple resonant modes to achieve multiband and extend bandwidth.The antenna is backward compatible with the communication standards of LTE1800/2300/2500 and UMTS2100/PCS1900/DCS1800.In addition,in order to improve the narrow bandwidth and low gain of the ZOR antenna in the low frequency range,a 4G LTE high-gain mobile phone antenna is designed,which covers the communication resonant bands of LTE1800/2300/2500 and UMTS2100/PCS1900/DCS1800/GSM900.Both mobile phone antennas can meet the design requirements of miniaturized multiband with good radiation performance and sufficient gain.