Twin delta loop antenna and its application to antenna with plane reflector

Abstract

AbstractIt is known that the impedance characteristics of polygonal loop antennas (e.g., triangular or rectangular loop antennas) vary considerably with the loop shape. This feature is considered to be an advantage of the polygonal loop antenna in designing practical antennas since the characteristics required for the intended purpose can be obtained by appropriate choice of the loop shape. Investigation of the polygonal loop antenna shows that an isoceles triangular loop antenna driven at its apex exhibits relatively broadband impedance characteristics. Utilizing this feature, we propose a twin‐delta‐loop‐antenna (TDLA), which is a coplanar twin triangular loop antenna that provides broadband properties with respect to both impedance and gain. This TDLA can be easily applied to a plane reflector antenna or the Yagi‐Uda array antenna to develop an antenna system with higher performance.In this paper, for wider application of the TDLA we present the detailed fundamental characteristics of impedance and directive gain of the TDLA. In addition, the design procedure for a plane reflector antenna using the TDLA is demonstrated for an example of practical application of the TDLA with low VSWR for coaxial cable without using a balun or impedance transformer.