Printed plane-filling fractal antennas for UHF band

Xuan Chen, Yaxun Liu, S. Safavi-Naeini
2004 IEEE Antennas and Propagation Society Symposium, 2004.  
Printed H i l k r t antenna has been used for UHF band since it is small, easy to fabricate and impdance-match to c m m " types of pl " IrrnSmissi"" lilm [I]. w n u y 121 studied the resonant frequency of wire Hilbert antenna in free space by using an approximate methnd. Anguera 131 studied B Verticil1 monopole Wlbert antenna. Chen [I] studied the charactcriStiCS of printed Hilbert Antenna used as B dipole. including rhe dependence of its remnant frequency and input impednnce on different
more » ... ters. current distriburion ai resonant frequency. miniaturization capability and radiation pattern. There are many different plane~filling frocral curvcs other than Hilkrt curve, far example. Moore. Peano. Wunderlkh I , 2 and 3 curves [5-71, as shown i n Fig.]. However. previous researches have focused on Hilbert curve, and how do other types of space-filling curves affect the current distribution, resonant frequency and input impedance of antennas shaped in them. is less explored. In this research we studied printed planefilling antennas of different shaper. including H i l k r t . Muore. Peano. Wunderlich 1. 2 and 3 curves. The input impedance and Current distribution are calculated through method of moments (MOM) with mired-potential integral equations (MPIE) formulation. The resonant frequencies are obtained by searching for the roots of thc imaginary part of the input impdance. The dependence of the resonant frequency on the shape and Size of the antennss are studied, and the current distributions along the antennas at resonant frequency are compared 11. SIMULATION METHOD The plane-filling fractal curves are generated through a recursive procedure based on descriptions given by (71. The printed antenna i s defined as a trace with specified width running along the curve. The trace is then meshed into triangles as shown in Fig. I The surface current density on the trace is unknown quantity to be solved. which is expanded by a sec o f RWG [SI basis functions 7" defined on the triangles, The MF' IE for PEC surface i s [91: a~~-I ? = . i .~~~4 ( i .~J . j [ ,~+ v~~i i ,~. d~~( 2 ) where S is the PEC surface. is the unit normal vector o f S . P is incident field. F~ and '" are Green's functions for i and 0 , respectively. The formulas of c d and is given by (91. and they are calculated by using complex image method (CIM) [IO]. ----The feed ~tructure i s modeled by a delta-gap voltage source. After applying the Galerkin's procedure [SI. (2) i s convened to a matrix equation: [Zbl= [VI (3) which i s then solved and the current distribulion is obtained. The input impedance is calculated based on the current distribution.
doi:10.1109/aps.2004.1330081 fatcat:4civsguqszgaflzx2jb5u3gt4y