Wireless Personal Communications (2007) 42:1–11 DOI 10.1007/s11277-006-9162-2 c  Springer 2006 Development of Multi-Broadband Planar Wire Antennas for Wireless Applications RONGLIN LI, GERALD DEJEAN, MANOS M. TENTZERIS and JOY LASKAR Georgia Electronic Design Center, School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA 30332-250, USA E-mail: rlli@ece.gatech.edu Abstract. A new type of multi-broadband antennas is developed for wireless applications. The broadband per- formance of this type of antennas is achieved by introducing a small gap on a wire loop while the multi-band operation is realized by simultaneously exciting one or more additional wire elements. Three antenna configura- tions are investigated for single-, dual-, and triple-broadband operations. The dual-broadband operation is obtained by employing a combination of a loop and a monopole. The triple-broadband antenna consists of a loop, a mono- pole, and an inverted-L structure. It is demonstrated that the multi-broadband antennas can achieve a bandwidth of 30% in the 1 GHz band, 50% in the 2 GHz band, and 40% in the 5 GHz band, which cover the frequency bands for AMPS/PCS, GSM/DCS, PDC/PHS, and IMT-2000 mobile communications as well as for 2.4-GHz and 5-GHz wireless applications. Keywords: multi-band antenna, broadband antenna, wireless applications 1. Introduction The growth in the wireless communication industry has resulted in a number of wireless standards used throughout the world. For example, the existing 1st and 2nd generation cellular mobile communication systems operate at the AMPS (824–894 MHz) and PCS (1850–1990 MHz) bands in America, at the GSM (880–960 MHz) and DCS (1710–1880 MHz) bands in Europe, and at the PDC (810–915 MHz) and PHS (1895–1918 MHz) bands in Japan. For future mobile communication systems, such as the emerging 3rd generation systems or beyond [1], new spectrum may be allocated around 2 GHz (e.g., already identified 1920– 2170 MHz band for UMTS [2] or IMT2000). In addition to different operating frequency bands adopted in cellular mobile communications systems, Wireless Local Area Networks (WLANs) also use different frequency bands. IEEE 802.11b, Bluetooth, and HomeRF oper- ate in the 2.4 GHz ISM band (2.400–2.485 GHz) [3] while IEEE 802.11a and HiperLAN (in Europe) will use the 5 GHz UNII band (5.15–5.35 GHz and 5.725–5.825 GHz for IEEE 802.11a, 5.15–5.25 GHz for HiperLAN1 and, 5.15–5.35 GHz and 5.47–5.725 GHz for Hiper- LAN2) [4]. Japan has started the development of standards for WLAN devices in the 5GHz band. The antenna will be a key component in the realization of the future wireless world where multi-mode terminals operating over several frequency bands are inevitable. For example, the 3G antennas will need to operate both in the IMT 2000 frequency bands and in the already established frequency bands. Also the future wireless terminals need to support high data