Multi-frequency Broadband Planar Antennas For Mobile Phone Handsets

Modern mobile phone handsets tend to be smaller, thinner and lighter. Also it prefers tobe able to transmit and receive image, voice and data anytime and anywhere in the future.Therefore, it is required for a mobile phone handset to support multiple networks and tooperate at multiple frequency bands. As a key component of a mobile phone handset, theantenna has to satisfy above requirements. So miniaturization and multi-broadband operationfor mobile phone antenna are the emerging trend and also the most challenging task forantenna design. In this paper, we focus on the technique for the design of multi-band andwideband planar antennas for mobile phone handsets.First we introduce the research background, significance and status of multi-band mobilephone antenna in Chapter1. Then we introduce the related theory including the ideal dipole,image theory, monopole antenna and planar monopole antenna in Chapter2. We alsodemonstrate the structure of the planar monopole antenna and its difference and relationshipwith microstrip patch antennas. The techniques for antenna miniaturization and wideband/multi-band antenna design are also introduced in this chapter.A triple-broadband planar antenna for mobile handset applications is proposed inChapter3. This antenna has a low profile, small size, broadband and can cover threefrequency bands, very suitable for applications in thin multi-functional smart mobile handsets.The total size of the antenna with the ground plane is115mm60mm, comparable to that ofan iPhone5. The triple-broadband antenna covers three frequency bands with a bandwidth of34%(814-1152MHz),47%(1670-2710MHz) and33%(4600-6400MHz) for VSWR<3.We extend the triple-broadband planar antenna to cover the3.5-GHz WiMAX band byintroducing an inverted-F monopole. A quad-broadband planar antenna is proposed inChapter4by making use of the previous triple-broadband planar antenna, covering theGSM/UMTS/LTE and WLAN/WiMAX bands. The quad-broadband antenna covers fourfrequency bands with a bandwidth of27%(198-1052MHz) for GSM850/GSM900,49%(1651-2735MHz) for GSM1800/GSM1900, UMTS, LTE2300/LTE2600,18%(3165-3780MHz) for3.5-GHz WiMAX, and35%(4400-6252MHz) for5-GHz WLAN, respectively.It is shown that antenna miniaturization and wideband/multi-band operation can be realized by using the meander line, multi-branched technology and the two-strip configuration.The multi-frequency broadband antennas proposed in this thesis can cover all existingfrequency bands for modern wireless applications.