RADIATIONPROPERTIESENHANCEMENTOF.PDF

Progress In Electromagnetics Research M, Vol. 5, 101–109, 2008 RADIATION PROPERTIES ENHANCEMENT OF TRIANGULAR PATCH MICROSTRIP ANTENNA ARRAY USING HEXAGONAL DEFECTED GROUND STRUCTURE F. Y. Zulkifli, E. T. Rahardjo, an dD. Hartanto Electrical Engineering Department University of Indonesia Depok, West Java, Indonesia Abstract—This paper presents a hexagonal shape defected ground structure (DGS) implemented on two element triangular patch microstrip antenna array. The radiation performance of the antenna is characterized by varying the geometry and dimension of the DGS and also by locating the DGS at specific position which were simulated. Simulation and measurement results have verified that the antenna with DGS had improved the antenna without DGS. Measurement results of the hexagonal DGS have axial ratio bandwidth enhancement of 10 MHz, return loss improvement of 35%, mutual coupling reduction of 3 dB and gain enhancement of 1 dB. 1. INTRODUCTION Microstrip antennas are widely used in various applications because of low profile, low cost, lightweight and conveniently to be integrated with RF devices. However, microstrip antennas have also disadvantages. One disadvantage is the excitation of surface waves that occurs in the substrate layer. Surface waves are undesired because when a patch antenna radiates, a portion of total available radiated power becomes trapped along the surface of the substrate. It can extract total available power for radiation to space wave. Therefore, surface wave can reduce the antenna efficiency, gain and bandwidth. For arrays, surface waves have a significant impact on the mutual coupling between array elements [1]. One solution to reduce surface waves is using electromagnetic bandgap (EBG) or photonic bandgap structure (PBG). 102 Zulkifli, Rahardjo, and Hartanto Recently introduction