Research On Miniaturized,Multi-band And Broadband Antenna In Wireless Communication

Antenna is an important component in wireless communication system.In recent years,with the rapid development of mobile communication technology and microwave millimeter-wave technology,the antenna,is facing an unprecedented challenge in its design.In order to facilitate the antenna integration,to prevent the interference of the same frequency band and improve the data transfer rate continuously,the performance of the antenna is required to be developed in the direction of miniaturization,multi-band and broadband.So how to design an antenna with these characteristics are the hot and difficult topics of antenna design in nowadays.This paper provides a brief overview of the research background and research situation at present,then described some of the most basic theory,performance parameters of the antenna,and summarizes the current mainstream methods to realize miniaturization,multi-band and broadband.Finally,combined with the current trend of antenna development,we designed three small,multi-band and broadband antennas: first of all,a novel single sided dual band printed composite loop antenna applied to WLAN/Wi MAX is proposed.The proposed antenna consists of a small inner rectangular ring,an external rectangular ring with three slits and a parasitic strip,and they are on the same side of the substrate.Through the feeding of the inner ring and combining dual rings and parasitic strip,three resonant frequencies can be achieved.The parasitic metal strip between rings can generate not only the new intermediate resonance frequency,but also improve the impedance matching of the low frequency band to a large extent.The dual band performance of a lower broadband covering 2.37-3.78 GHz and a higher frequency band covering 5.15-5.85 GHz can be obtained through the magnetic-electrical coupling.Then,a composite multi-mode printed loop antenna based on the deformed split ring resonator?DSRRs?is proposed,which is used for broadband wireless communication.The proposed antenna is composed of an external split ring,an internal closed ring and a parasitic strip.The size of the two rings is very different.It can be considered to be a deformed SRRs.With the orthogonal radiation mode of the two rings,the multi-mode loop antenna can realize multi-band resonance.By cooperating with the two coupling rings,the parasitic strip is close to the feeding gap of the inner ring,not only introducing the new resonance frequency at the high frequency band,but also greatly improving the impedance matching of all the high frequency bands.The proposed antenna not only covers the first split ringmode of 816 MHz,but also shows the broadband characteristics covering 2.3-4.6 GHz(reflection coefficient |S₁₁|?-?10?dB,67% fractional bandwidth).Finally,we proposed a novel compact planar ultra wideband handset antenna with a L-shaped extended stub.The proposed mobile phone antenna consists of two planar bending monopole radiation components,namely the main antenna and auxiliary antenna located at the diagonal corners of the standard cell phone printed circuit board with the size of 136×68 mm².Each radiating element consists of two arms and a L-shaped extended stub,to achieve multiple resonances,ultra-wideband impedance matching and compact size together.The effect of L-shaped stub is also studied in detail.The proposed antenna has the compact size of 31.4×12 mm²,and has the characteristics of printed simple structure and almost full band coverage?GSM850,DCS1800,PCS1900,UMTS,LTE,Wi MAX and WLAN?.So it is very suitable for mobile communication system.Finally,the work of this paper is summarized and the future work is forecasted.Antenna simulation,design and optimization is done in HFSS and CST.In order to verify the validity of the simulation design,the actual objects are processed and measured according to the final optimized size.The measured results show that they are in good agreement with the simulation results,which verify the validity and correctness of the simulation.The designed three antennas satisfy the requirements of miniaturization,multi-band and broadband basically.