Summary
International Symposium on Antennas and Propagation
2010
Session Number:2WC1
Session:
Number:2WC1-8
Low-Profile Leaky-Wave Antenna with Monopolar Radiation Pattern Using Composite Right / Left-Handed Transmission Line
Woo-jin Kim, Naobumi Michishita, Yoshihide Yamada,
pp.-
Publication Date:2010/11/23
Online ISSN:2188-5079
Summary:
A radio-on-fiber system has been developed for enabling cellular mobile communication in radio-blind areas, such as highway tunnels and underground shopping malls [1],[2]. A distributed antenna system consisting of coaxial cables and couplers has been specifically designed for use in the aforementioned radio-blind areas [2], [3]. In an in-building antenna distribution system, the antenna is installed on the ceiling, hence a low-profile antenna is preferred. Authors have reported a low-profiled top loaded monopole antenna (TLMA) [4],[5]. When the height of the TLMA is 0.03?, bandwidth of 17.5 % is achieved. However, when the height of TLMA is less than 0.03?, impedance matching is not achieved [5]. To overcome this problem, a leaky wave antenna is considered as the low-profile and broadband antenna. The leaky-wave antenna in the metamaterialbased mushroom structure has been proposed for a conical beam antenna application [6],[7]. However, the effective feeding structure has not been developed for broadband impedance matching. This paper presents characteristics of the leaky wave antenna using composite right/left handed transmission line (CRLH-TL) with mushroom structure. A unit cell using mushroom structure is designed. A centre-feeding structure, for impedance matching of leaky wave antenna, is also designed. Then, 1D low-profiled leaky wave antenna is designed by connecting the feeding structure and CRLH-TL. This antenna has monopolar radiation pattern. Finally, bandwidth and gain characteristics of the leaky wave antenna are investigated.