Study Of Metamaterial Broadband Antennas And Novel Wearable Antennas

With the rapid development of the handheld communication devices and ultra-wideband(UWB) wireless communication technology, the electronic equipment is getting highly functional, and the signal bandwidth is also increasing unceasingly. Higher requirements on antenna performance in the wireless communication system are demanded, mainly reflected in increasing bandwidth, miniaturization, easy integration, high radiation efficiency and so on. Therefore, it is particularly important to carry out in-depth research on the broadband antenna theories and techniques.The theories and techniques of Metamaterial Broadband Antennas, Wearable Broadband Antennas, and UWB printed planar antennas are deeply studied in this thesis. Approaches based on metamaterial to increase the antenna bandwidth are researched, and the design methods of novel wideband metamaterial antennas are explored. The characteristics of coplanar waveguide(CPW) are discussed, and a novel CPW-fed wearable antenna is then proposed. After that, the design principle of UWB planar monopole antennas is further studied, and a novel UWB printed monopole antenna is designed. The major work and innovations in this thesis are as follows.1. Propose a new method of integrating metamaterials, such as composite right/left-handed transmission line(CRLH TL) and complementary split ring resonator(CSRR), into feed network for broadband antenna. Designed two novel metamaterial broadband antennas, and one of them had been fabricated and measured. The proposed design is different from the traditional design methods including integrating metamaterials into antenna radiating elements and making radomes with metamaterials. In this thesis, by changing the feed network, the purpose of reducing the resonant frequency and increasing the bandwidth are reached without increasing the size of antennas.2. Three novel wearable broadband antennas with daily clothing textile materials as substrates are presented and fabricated. The objectives of integrating the wearable antennas into daily clothing are achieved, which can greatly improve the adaptability, flexibility and concealment of wearable antennas. At the same time, these noval design lay the foundation for using the emergency relief, fire fighter clothing and other textile materials as substrates to design specialized wearable antennas.3. The novel CPW-fed wearable antenas are proposed. With the superiority of CPW-fed antennas, where the ground and the radiation patch are placed on the same side of the substrate, the antenna with denim as substrate can be attached to the surface of daily clothing directly, the process of antennas manufacturing is simplified, and the difficulty of antenna integration is reduced.4. The time domain and frequency domain characteristics of UWB antennas with different structures of the ground and the radiation patch are studied. According to the modeling analysis and optimal design, a novel miniature UWB planar monopole antenna is presented and fabricated. The stucture of radiation patch is improved to extend radiation boundary and reduce the resonant frequency without increasing the antenna size. A method of enhancing impedance matching and increasing the bandwidth of the antenna by integrating two symmetric triangles into the traditional ground is proposed. Then the UWB design of antenna is achieved.