Research On WLAN/WiMAX Antenna For Compact Size And Frequency Selective Surface For Ultra Wideband

The antenna is one of the important components in the radio, television, navigation, andother cordless telephone systems. With the rapid development of wireless communications,WLAN (Wireless Local Area Network,2.4-2.484GHz,5.15-5.35GHz, and5.725-5.825GHz),and WiMAX (Worldwide Interoperability for Microwave Access Network,2.5-2.69GHz,3.3-3.79GHz and5.25-5.85GHz) wireless communication system have extensively been usedin commercial, medical, and industrial applications. The multiband antenna must have simplestructure, small size, light weight, low cost, and easily integrated with RF circuits and theantenna must has high gain in base station.This paper is committed to study the miniaturization and multiband antenna for WLAN/WiMAX application, and studies the FSS (frequency selective surfaces), as the antennareflector to increase the gain of the ultra-wideband antenna to meet the modern wirelesscommunication requirements. The FSS is one type of EBG (Electromagnetic Band Gap)structures. The main research work is as follows:First, an overview of the development of multiband antennas for WLAN/WiMAXapplication is introduced, and give a brief introduction and analysis to the several techniquesfor achieve multiband and compact size.Secondly, it analyzes the basic theory of microstrip antenna and the main parameters,which will provide a theoretical basis for future research work.Then, we propose two different compact and multiband antennas for WLAN/WiMAXapplication, the main technical as follows:1. A two-band monopole antenna with a compact size of15×30×1.2mm3is proposed tocover the frequency band for WLAN and WIMAX application. The antenna is mainly consistsof the radiating E patch and the slit in the ground. The antenna has two bands, which are from3.20GHz to4.07GHz and from5.08GHz to5.85GHz, and the frequency can be controlledindependently. The antenna applied for WLAN5.2/5.8GHz and WiMAX3.5/5.5GHz.2. A triple-band monopole antenna with a compact size of15×30×1.2mm3is proposed tocover the frequency band for WLAN and WIMAX application. The antenna is mainly consists of notched rectangular micro strip, S-type micro strip and defected ground. The multibandantenna has three operation bands, which are from2.4GHz to2.51GHz, from3.20GHz to4.07GHz and from5.08GHz to5.85GHz, respectively. The developed antenna can apply for2.4/5.2/5.8GHz WLAN bands and3.5/5.5GHz WIMAX band. The multiband antenna isfabricated, and experimental results are presented.Finally, in the theory and study of the structural basis of frequency selective surface ofthe FSS, an ultra-wideband band stop frequency selective surface with superior reflectiveperformance is introduced. The FSS has wideband, which is from3.20GHz to13.2GHz. TheFSS used as a reflector to improve front-to-ratio and the gain of the antenna.