具有和不具有空气隙的圆环微带天线输入阻抗的理论分析

A THEOREICAL STUDY OF INPUT IMPEDANCE OF AN ANNULAR-RING MICROSTRIPANTENNA WITH AND WITHOUT AN GAP

提供了圆秆微带无线（具有和不具有空气隙）在同轴线馈电情况下输入阻抗的理论分析。推导出未知贴片电流的积分方程。整个推导过程是在汉克尔变换域内进行，对于地片电流引人一套基函数，应用伽略金法及Ｐａｒｓｅｖａｌ关系，推导出矩阵方程，由此可以解出贴片电流，推导出输入阻抗的表达式，并包括了表面波的影响。给出了当空气隙宽度为不同数值时输入阻抗的计算结果。由计算结果表明：当空气隙宽度增加时，谐振频率和带宽均增加。

A theoretical study is presented of the input impedance of coaxilly-fed an-nular-ring microstrip antenna with and without an air gap.Integral equations for unknownpatch current are formulated.The derivation is performed in the Hankel transform domain.Aset of entire basis functions are introduced for the patch current.Galerkin's method tegotherwith Parseval's relation is used to derive a matrix equation from which the patch current maybe solved fr.The expression for input impedance is derived and effects of surface waves areproperly included The calculated results for the input impedance are poresented for differentvalues of the air gap width.It is shown from,the calculated results that as the air gap widthincreases bith resonant frequency and bandwidth increase.