International Journal of Technology (2016) 4: 683-690 ISSN 2086-9614 © IJTech 2016 LEFT-HANDED METAMATERIAL (LHM) STRUCTURE STACKED ON A TWO- ELEMENT MICROSTRIP ANTENNA ARRAY Fitri Yuli Zulkifli 1* , Nugroho Adi Saputro 1 , Basari 1 , Eko Tjipto Rahardjo 1 1 Antenna Propagation and Microwave Research Group, Department of Electrical Engineering, Faculty of Engineering Universitas Indonesia, Kampus UI Depok, Depok 16424, Indonesia (Received: January 2016 / Revised: January 2016 / Accepted: January 2016) ABSTRACT Antenna can be one of the largest components in a wireless device; therefore antenna miniaturization can reduce the overall size of wireless devices. One method used to reduce the element size of an antenna is by using metamaterial structures. This paper discusses a Left- Handed Metamaterial (LHM) structure stacked on a two-element microstrip antennas array for miniaturization and gain enhancement at a frequency of 2.35 GHz. To observe the impact of the LHM structure on the antenna, first this paper discuss the design of a conventional rectangular shape microstrip antenna without a LHM structure, then a design of the LHM structure which shows both negative permittivity and negative permeability. This LHM structure is then implemented on a conventional single element microstrip antenna and on a two-element microstrip antennas array. Results and discussion of implementation of the LHM structure on the conventional microstrip antenna is provided in this paper. The results show that good agreement between simulated and measured results has been achieved. The simulation results show that the antenna works at a frequency of 2.29–2.42 GHz with a bandwidth of 128 MHz (5.4%) and a gain of 8.2 dBi, while the measurements show that the antenna works at a frequency of 2.26–2.41 GHz with a bandwidth of 146 MHz (6.21%) and a gain of 8.97 dBi. In addition, by comparing the substrate dimension for the two element array antennas, with and without the LHM structure, shows a 39% reduction is achieved. Keywords: Array antenna; Metamaterial structure; Microstrip antenna; Split ring resonator 1. INTRODUCTION Currently, the high demand for communication technology shows the need for a wireless technology system to be integrated into a single chip. Miniaturization of antenna, that is one of the largest components in the devices, play an important role in improving the performance and reducing the overall size of wireless devices. Meanwhile, during the last decade, many papers investigated and analyzed artificial metamaterials due to their unique characteristics, such as backward wave propagation and negative permittivity and/or negative permeability (Smith et al., 2000; Erentok et al., 2005). Metamaterials also have been used for antenna miniaturization (Singh, 2010; Rahardjo et al., 2012). Several methods have been used to miniaturize antennas, which include the Composite Right/Left-Handed Transmission Line (CRLH-TL) antenna structure (Selvanayagam, 2010) and the Complementary Split Ring Resonator (CSRR). Various methods are implemented by etching the ground plane (Lai et al., 2007), by using the *Corresponding author’s email: yuli@eng.ui.ac.id, Tel. +62-21-7270078, Fax. +62-21-7270077 Permalink/DOI: http://dx.doi.org/10.14716/ijtech.v7i4.2865