A Compact Nine-Band Frequency Reconfigurable Antenna for Lte/Wwan/Wlan Handset Applications

Abstract

A frequency reconfigurable antenna suitable for handset is proposed in this research. The antenna structure includes an inverted-L shaped monopole and two meandered shorting strips. A wide high frequency band is excited from the inverted-L shaped strip monopole by direct feeding, and then the low and middle frequency bands are excited from two meandered shorting strips. Furthermore, a PIN switch diode is added at the end of shorting strip1 to implement the frequency reconfigurable property. The antenna was fabricated on an FR4 substrate and with a volume of only 9 × 50 × 5 mm 3. It can cover the operation bands of LTE700/2300/2500, GSM850/900/1800/1900, UMTS2100, and WLAN2400. The detailed considerations and analyses of the design are studied in this paper. 1. INTRODUCTION Antenna is an important component for all kinds of wireless transmission and is also one of the necessary devices for data transmission and reception. For nowadays mobile communication, the antenna not only promotes the transmission quality, but also changes to concealed forms instead of exposed ones for good looking, convenience, and efficiency. Besides, due to multipurpose usages of handset, the design of a multiband antenna becomes an important issue for handset applications. Most researches on handset antennas are about planar antenna structures which are easy to integrate inside handset, such as planar inverted-F antenna (PIFA) [1, 2], loop antenna [3], and monopole antenna [4]. For keeping the antenna sizes compact, more researches for three-dimensional antennas are proposed to scale down the volume of antenna [5-7]. Frequency reconfigurable antennas [8-12] were designed and proposed recently for small antenna, with PIN switch diode [8-10], RF switch [11], or micro-electro-mechanical systems (MEMS) [12] for switching paths to excite various frequencies and shorten the length of exciting elements, then scale down the antenna sizes. Furthermore, reconfigurable polarization antennas [13-15] suitable for switching radiation styles which are directional and omnidirectional. In this research, a frequency reconfigurable antenna suitable for handset is proposed, including an inverted-L shaped monopole and two meandered shorting strips. A wide high frequency band is aroused from the inverted-L shaped strip monopole by direct feeding, and then the low and middle frequency bands are excited from two meandered shorting strips. Furthermore, an Avago HSMP3894 PIN switch diode is added at the end of shorting strip1 to implement the frequency reconfigurable property. The operation bands of the antenna can cover LTE700/