《A Compact Slot Antenna Utilizing a》.pdf

IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, VOL. 56, NO. 3, MARCH 2008 675 A Compact Slot Antenna Utilizing a Right/Left-Handed Transmission Line Feed Yu-Shin Wang, Min-Feng Hsu, and Shyh-Jong Chung, Senior Member, IEEE Abstract—A novel compact planar antenna utilizing cascaded right/left-handed transmission lines is proposed. The significance of layout planning with respect to radiation is investigated and dis- cussed in this paper. Two segments of transmission lines of the same electrical length with opposite signs are cascaded to provide zero phase at the operation frequency. The closed-form formulas for the equivalent circuit of a transmission line are used for circuit de- sign. Both antenna layout and radiation mechanism are discussed. For experimental demonstration, the proposed antenna operating at 2.45 GHz was implemented on an FR4 substrate. The topology using several patches has quite smaller size than the conventional patch antenna. Besides, a fairly omnidirectional radiation pattern was measured. Index Terms—Antenna layout, left-handed (LH) transmission line, metamaterial, printed antenna, radiating edge. I. INTRODUCTION Fig. 1. Geometry of the proposed planar antenna. ETAMATERIALS have recently been extensively dis- Mcussed and studied. This kind of artificial structure has host RH TL. The zeroth-order resonance (ZOR) [28] makes been utilized for many guided and unguided wave applications. use of the opposite phase properties of RH and LH TL and has Their unique characteristics have been considered to be valuable been proved experimentally. Small planar antennas utilizing the topics. Spe