SAR investigation of Near-Field Control for Mobile Phone Antennas

• Main Authors: Cheng-Chang Chen, 陳誠章
• Other Authors: Sheng-Lyang Jang
• Format: Others
• Language: en_US
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/s93m25

博士 === 國立臺灣科技大學 === 電子工程系 === 105 === In this thesis, it is proposed to use the control field to make the design of the antenna can easily meet the requirements of SAR, the other antenna design also introduced the use of loop structure to produce reverse current to make the energy is more dispersed, less likely to form a centralized hot spots, It is also helpful to reduce the SAR value, and the application of Adjacent Frequency design, multi-path to produce multi-resonant, to achieve the effect of broadband. The first propose antenna, it is shown that the one fifth wavelength radiator combines with a printed ground-line which protrudes from ground-plane jointly with parasitic metal-loading, which can be used to control the near-fields of a mobile phone antenna. The human’s hand and head effect on impedance bandwidth and radiation characteristics of the proposed antenna is studied. The input power of 24dBm in CDMA, GSM and WCDMA bands, and the input power of 21dBm in DCS and PCS bands all meet the specific absorption rate (SAR) limit of 1.6 mW/g and hearing aid compatibility (HAC) of M3 and M4 level. The second propose antenna, it is a novel multi-band broadband antenna for mobile handsets application. It is proposed and analyzed in this paper. An asymmetric T-type monopole antenna with a shorting-line is designed to be operated in long term evolution (LTE, 698MHz-960MHz, 1710MHz-2170MHz, 2500MHz-2690MHz) and wireless local area network (WLAN, IEEE 802.11ac, 5150MHz-5850MHz) bands. The experimental results indicate that the bandwidths for VSWR of 3:1 achieved were 37.75%, 24.63%, 11.46% and 21.76% at 800MHz, 1900MHz, 2600MHz and 5500MHz, respectively. The specific absorption rate (SAR) for an input power of 24dBm in LTE band, and an input power of 13dBm in IEEE 802.11ac band meet the SAR limit of 1.6 mW/g. Experimental results verify the prediction of the theoretical analysis.