Research And Design Of Novel Dual Band Ultra Wideband Dual Polarization Antennas

With the popularity of 3G communication technology and the ris ing developement of 4G communication, it is extremely urgent to find the antenna with wide spectrum and high efficient spectrum utilizatio n. Ultra wideband technology has the characteristics of high transmission rate, large capacity, low cost, small power consumption, good secrecy performance, strong anti- interference ability, which makes the ultra wideband technology becomes one of the most competitive technology and the most prosperous development prospect. But common ultra wideband antenna has been difficult to meet the requirements of modern high efficiency of a high degree of integration, so multi-polarization working form should be get further attention. Ultra wideband dual polarized antenna as a new kind of antenna, is now widely used in the communication fields. Another important research direction of the antenna is the multi- frequency performance of the antenna itself. As the number of mobile communication users increased, the existing spectrum resources become more and more scarce, which also requires the mobile terminal to achieve dual frequency or multi- frequency working form. Therefore, the research and design of dual band, ultra wideband, dual polarization antenna has important engineering practical significance.This paper gathered ultra wideband antenna, dual band antenna and dual polarization antenna together as the researc h object and researched on the ultra wideband technology, dual band technology and dual polarization technology, which considered on characteristics influence ike voltage standing wave ratio, isolation and cross polarization level through three completely different forms. And then we made comprehensive design of ultra wideband dual polarized antenna, dual band dual polarization antenna and dual band ultra wideband dual polarized antenna. Thus, the final design was in accordance with the design requirements and the actual demand of the antenna.Firstly, the antenna of the basic theory and technical indicators were briefly introduced, and the single dual band antenna, ultra wideband antenna and dual polarized antenna basic theory and design technology were analysed. Return loss, isolation and cross polarization level as technology parameters were studied through the antenna on the basis of the theory.Secondly, the design and implement of an ultra wideband dual polarized antenna with a single band that applied with H-shaped slot coupled feed and stepped groove structure is accomplished. Through this antenna, a preliminary analysis that aperture coupled feeding structure is important for reducing the Q value of the antenna, that patch loading technology and meandering are of great feasibility for widening the band improving radiation pattern, and that orthogonal feeding structure can realize the effectiveness of dual polarization with high isolation are showed.Next, a dual band dual polarization antenna that applied with fork-shaped feeding and symmetrical double arching surface nesting structure is designed and implemented. Through this antenna, a preliminary analysis is carried out with great feasibility when realized with dual polarized patch orthogonal, and fork type coupling feed ing to two stubs radiating realized the effectiveness of excellent characteristics of dual frequency antenna.Finally, the design and implementation of the three ultra wideband antennas are accomplished, thus finally completed the dual band ultra wideband dual polarization antenna that applied with symmetric U-shaped radiating surface structure with open wide slot and double side balun form feeding, which has a full coverage of the 2G and 3G network band. Through the final antenna, we made an analysis on the feeding balun structure, which showed the importance way to broaden the frequency band. The symmetric U-shaped radiating surface structure with open wide slot is also important in the practical applicatio n for antenna design. And the double side balun form feeding impedance matching stood on the key position in lowering return loss in the design of ultra wideband antenna. And it realized the effectiveness of high isolation and high cross polarization level of dual frequency antenna when used ±45 degree vertical placement of the who le space of the radiation patch.