Influence of mutual coupling and feed network on directivity and gain [array patch antennas]

Author

Gottwald, G. ; Wiesbeck, W.

Author_Institution

Inst. fur Hochsfrequenztech. und Elektronik, Karlsruhe Univ., Germany

fYear

1993

fDate

1993

Firstpage

761

Abstract

A detailed analysis of the influence of mutual coupling (MC) on the directivity and gain in array patch antennas is carried out. MC changes the active input impedances depending on the actual excitation currents of the array elements. In combination with the feed network this causes an increase of loss and a change of excitation currents. This is calculated by the multiport theory, where the antenna elements are represented by the mutual impedance matrix and the feed network is described by the transmission line theory. By changing the input impedances the input power is altered too. A formula is derived to determine the directivity enhancement of an nxn-array compared to a single element, if the MC is known. The theory is applied to 2×2- and 4×4-array patch antennas at 24.125 GHz±10% under consideration of dispersion effects of the microstrip feed network

Keywords

antenna feeders; antenna phased arrays; antenna theory; electric impedance; microstrip antennas; microwave antenna arrays; multiport networks; transmission line theory; 2*2 array; 24.125 GHz; 4*4-array; SHF; active input impedances; array elements; array patch antennas; directivity enhancement; dispersion effects; excitation currents; feed network; gain; input power; loss; microstrip feed network; multiport theory; mutual coupling; mutual impedance matrix; transmission line theory;

fLanguage

English

Publisher

iet

Conference_Titel

Antennas and Propagation, 1993., Eighth International Conference on

Conference_Location

Edinburgh

Print_ISBN

0-85296-572-9

Type

conf

Filename

224810