Design Of Multi-band Antenna Utilizing Composite Metamaterials

In recent years,The prodigious rate of development of wireless communication technology has far exceeded our imagination.It can be never stemmed for the demand of design the multiband antenna.Antenna,as a necessary component for receiving and transmitting electromagnetic wave in radio communication system.The main work is to convert electromagnetic wave into high frequency signal energy and send it to the receiver,or transmit the high frequency signal energy emitted by the transmitter into the electromagnetic wave and radiate it into the space,which can realize the transmission of electromagnetic wave between any two points in free space.Therefore,the antenna plays a key role on the performance of wireless communication systems.On the basics of the powerful communication demand,two antennas work in WLAN/WIMAX bands designed.Moreover,including an ultra wide band antenna.Main work:The first part,classified and summarized some methods to realize the design of the antenna cover the WLAN/WIMAX frequency bands and explain the design principle separately,and keep on research.The second part,designed of an antenna which can cover WLAN/WIMAX frequency bands based on monopole antenna,some advantages as follows:high gain,high impedance bandwidth,high efficiency,omnidirectional radiation,simple structure,the CPW fed structure not only broadens the bandwidth of the high frequency band,and the impedance matching of the antenna get optimized.The third part,an ultra wideband antenna covering the whole band of WLAN/WIMAX can be designed using an open ring,a single monopole produces one resonant mode only,an open ring can be regarded as two monopoles on both sides of the opening,produce different resonance frequency points,also,the whole ring as a large monopole,another resonant mode will be produced,based on this principle,multi band can be realized by using only one open loop.By changed the distance between the inner and outer rings on the ring,ultra wideband can be achieved,Some slots are etched on the ground plane to change the current direction of the patch,then the antenna matching get improved.