Summary
International Symposium on Antennas and Propagation
2009
Session Number:2B1
Session:
Number:2B1-4
Ultra Low Profile Inverted L Antenna on a Finite Conducting Plane
Tetsuya Yamashita, Mitsuo Taguch,
pp.361-364
Publication Date:2009/10/21
Online ISSN:2188-5079
Summary:
The input resistance of a horizontal dipole located very close to a perfect electric conducting plane becomes lower due to the existence of a metallic structure, and it approaches zero as the distance is decreased toward zero [1] - [3]. Most people tend to consider that the electromagnetic fields from the antenna and its image cancel out each other due to 180 degree phase difference. An "ultra low profile dipole (ULPD) antenna", which is a dipole very closely located to a conducting plane was proposed to solve the impedance matching issue [4]. A half wavelength dipole is excited at the offset points from the center, so that reasonable impedance can be obtained even with a conducting plane in proximity to the dipole. The maximum gain of 8.4 dBi, which is higher than that of a half-wave dipole with a quarter wavelength distance between the dipole and the reflector, is obtained. The return loss bandwidth for 10 dB is about 2%. In this paper, an inverted L antenna located very close on a finite conducting plane is proposed and numerically analyzed. This antenna is excited on the horizontal element. The input impedance of this antenna is matched to 50 ohms and its gain becomes more than 4 dBi. In the numerical analysis, the electromagnetic simulator WIPL-D based on the method of moment is used [5].