Designs And Implementation Of Wide-band Dual-polarized Log Periodic Dipole Antenna

Antenna which can transmit and receive radio wave is an important microwavecomponent. With the development of science and technology, the wide band anddual polarization performance of antenna is required. Log-Periodic Dipole Antenna(LPDA) is widely used due to its simple structure, good performance and widebandwidth. This thesis researches the method to realize wide band and dualpolarization antenna base on LPDA. The main contents of this thesis are as follows：Firstly, the theories of LPDA such as basic principles, structure characteristics,electrical features and analytic methods are introduced. The methods how to designLPDA and calculate parameter of antenna are discussed.Then, considering working frequency band2-6GHz, dual polarized LPDA withA structure and B structure are designed and simulated on the electromagneticsoftware CST. The simulated results of radiation pattern, Voltage Stand Wave Ratio(VSWR), and isolation degree are given in the paper. According to simulationresults, antenna with B structure has better performance than A structure which isadaptive to wider working frequency bandwidth and suitable for some specialoccasions.Finally, dual polarized LPDA with A structure and B structure are fabricatedbased on simulation models. Both the dual polarized LPDAs are measured inmicrowave anechoic chamber. The measured results of VSWR, port isolation,power pattern, axial ratio pattern, gain pattern, and beam width are given in thepaper. The analysis of these measured results indicates that the fabricated LPDA canmeet the proposed requirement. However, the measured results are not so good assimulation results due to the limit of machining accuracy level.