Design of internal antenna for multiple applications

Abstract

Due to the development of modern integrated circuit technology and the requirements of the consumers, the sizes and weights of mobile handsets have rapidly been reduced. Antennas are considered to be largest components of integrated wireless systems. Therefore antenna miniaturization is a necessary task in satisfying the demand for the market. In addition to the reduced antenna sizes, mobile phones require multiple frequency bands for cellular applications, PCS and other wireless communications. Moreover, Wireless communication devices have also become associated with possible health effects surrounding the exposure of humans to electromagnetic radiation. One of the most widely used parameters for the evaluation of exposure is the specific absorption rate (SAR). Having low SAR not only reduces electromagnetic exposure but also increases the efficiency of the antenna systems and therefore the battery life of the communication systems. In this thesis, three infernal antennas for different bands have been proposed. And we discussed about the cable effects of radiation patterns for exact measurement. At first, a novel compact shorted patch antenna with the bowtie- type patch and the dual triangle portion to obtain a large bandwidth (790 MHz ~ 970 MHz) is presented. Using shored patches by via holes, size reduction of 95.7 ％ is achieved with comparing to those of the conventional half-wave patch antenna. Moreover, it has 10 dB return loss bandwidth of 20.4 % for GSM and CDMA bands. The maximum measured and simulated radiation gain is 1.54 dBi and 1.9dBi, respectively. This antenna shows not only a compact and a thin profile but also wideband characteristics. Secondly, the novel compact cable-fed antenna is proposed and designed. And the measured and simulated results are represented. This proposed antenna was printed on FR4 substrate with 1 mm thickness which has relative permittivity 4.6. To achieve the compact and wide band characteristics, two inducti...