SOME INVESTIGATIONS ON A MICROSTRIPLINE SLOT ANTENNA

Abstract

In recent years, the printed slot antennas fed by microstripline are gaining wide popularity because of their numerous advantages.They can be used in various ways in microstrip circuit design such as a feed for microstrip patch antenna, a radiating element by itself or In an array of slot radiators. The slot radiators have the advantage of very low cross polarization and spurious signal-free radiation patterns as compared to patch radiators. In the present work, a moment method f'or•mulation has been presented for a general microstripline fed slot antenna. Equivalence principle, in conjunction with the boundary conditions, has been used to set-up two coupled integro-differential equations. These are then reduced to matrix form using the method of moments. The analysis is quite general, in the sense that no restrictions have been imposed on the size of the slot & line. The line has been assumed to be offset from the center of the slot and terminated in an open-circuit. In order to be able to use the printed slot as an element in a phar,c,d array, It.. is necessary t,o car•ry out. it de t a i l ed study of its radiation characteristics which is lacking in the liturature. Therefore, some experimental investigations were carried out on the printed slot antenna fed by an infinite microstripline. Experimental results have been reported here, on the -input characteristics, gain and the radiation pattern of an antenna operating at 10 GIfz. Further, the dependence of Input impedance and radiation pattern on the slot to reflector spacing has also been studied in detail .