Microstrip Antenna Based On Modern Communications

In modern wireless communication,antennas play the important role in transmitting and receiving radio waves,and a good performance antenna is the premise to complete the communication tasks for communication systems.At present,the pursuit of wireless communication technology is mainly in terms of the dependence on intelligent and multi-function handheld devices or the high transmit speed requirements in information.The intelligent and multi-function equipments mean the antenna of multi-frequency,while antenna bandwidth determines the communication efficiency.Therefore,miniaturization,multi-frequency and broadband antennas become the main trend in the design of the antenna,which play an important role in the development of modern communication systems.In this paper,the theory of the microstrip antenna,as well as the develop trend and technology of multi-frequency and broadband antennas have been introdused,the research and design work of the microstrip antenna are finished by three parts.The first part mainly designed two kinds of multiband microstrip antenna.Firstly,considering the miniaturization of the antenna,this paper using the full filling and self similar Sierpinski triangle fractal structure to design the antenna,and adding easy adjust branches to increase the resonance frequency and broad the bandwidth of the antenna.Secondly,the basic model of coplanar waveguide is used to design the antenna,which can generated two resonance frequency through using U-shaped radiation patch,and realized circular polarization by introducing asymmetric perturbation on the coplanar structure.Then a dual band circular polarization microstrip antenna for WiMax and WLAN has been designed.The second part mainly completed the research and design of the ultra-wideband(UWB)microstrip antenna.Firstly,based on the advantages that PIFA structure itself has low Q value,easy to broade the bandwidth and has no need to add the additional matching network to realized a wide band antenna.The miniaturization of the antenna can be achieved by bending the radiation branches,and the antenna bandwidth can be improved by adding the short circuit patch which can make the appropriate coupling between the radiation patches.The proportion bandwidth of the final design antenna can reached 63%at the low frequency,and the test and simulation results of the antenna matched well.Secondly,an UWB microstrip antenna with bandwidth of up to 74%was designed by cutting the rectangular radiation patch to form a multilateral radiation patch and by using concave floor to improve the bandwidth.But taking into account that the UWB antenna will be influenced by the electromagnetic interference of the WLAN band in the propagation of electromagnetic wave,U-shaped slot trap structure is added to eliminate the existing electromagnetic interference problem.Eventually,the UWB antenna can realized the effective notch of the WLAN band and can improved the anti-interference ability.In the third part,a simple 2 x 2 microstrip antenna array has been studied.The rectangular radiating patch with open U-shaped groove is used as the basic radiation element.The performance parameters of the microstrip array antenna are compared with the general microstrip cell antenna contrast,the simulation pattern of the microstrip antenna array has a strong direction,and the gain is more high relatively which can up to 13.5dB,the bandwidth also has been improved.