Research Of Marchand Balun Dipole And Its 1D Cylindrical Conformal Array

The purpose of this thesis is to study the applicability and limitations of Marchand balun composed of coaxial lines and its equivalent circuit for dipole.A simplified method with equivalent circuit and ideal antenna is discussed to analyze the radiation characteristics of real antenna,which can significantly improve the calculating efficiency,save the software running time and reduce the dependence of the complex antenna model for hardware.First of all,the resonant dipole with balun respectively working in the UHF and S frequency band is studied.Through the simulation results and the equivalent calculation results,compared with the antenna size,the bigger the balun size,the greater the effect of balun on the radiation pattern.Thus restricted by the real coaxial line size,the error of equivalent results will be significant on high frequency.Than 2 elements serial array and parallel array with different element spacing are studied,the simulation results and the equivalent results are discussed in these cases of presence of mutual coupling.As for serial array,balun is a big influence on radiation pattern,as the elements spacing is small,but the calculation result of input impedance is quite precise.As for parallel array,error of equivalent padiation pattern is rather small,and the relative error of input impedance is big when the elements spacing is tiny.Than the uniform linear array and 1-D cylindrical conformal array are studied.Compared with simulation results,equivalent calculation results error are small,further illustrate the feasibility of the simplified method using the equivalent circuit and the ideal antenna to analyze the actual antenna radiation characteristics applied in uniform linear array and 1-D cylindrical conformal array.At last,a 21-elements uniform linear array and 1-D cylindrical conformal array are proposed,take them as examples,their scanning characteristics are analyzed with the simplified method mentioned above.calculating their scanning characteristics usually need workstation and will take quite a long time but with the simplified method,same work can be accomplished on PC and won't spend too much time.