Study And Design On Asymmetric Wearable Dipole Antenna

With the rapid development of mobile wireless communications, people’s life has been better and more convenient. Various wearable devices have gradually emerged into our daily lifes. Therefore, it is a challenging task to develop high performance wearable antennas. In order to mitigate the antenna’s performance deterioration caused by the human body, additional loops are incorporated with a wideband dipole. The loops can i) widen the impedance bandwidth by minimizing the reactance of the antenna, ii) increase the antenna’s directivity and iii) act as wearable accessories for easy mounting to the users’ bodies as well. Then, the interaction between the antenna and the human body can be reduced. Then, by using simulation software to analyze and verify the operation principles and through a further structural improvement, compact wearable antennas are designed on different dielectric substrates respectively. The main content of this thesis is organized as follows:1. First of all, a wide-band loop-dipole combined antenna is proposed and a conventional asymmetric antenna is used as the initial stage of this design. Besides, the antenna is composed of an asymmetric dipole and two loop structures. The loops can increase the antenna’s directivity and act as wearable accessories for easy mounting to the users’ bodies as well. The reflection coefficient, radiation pattern and gain are analyzed by using CST simulator. It is demonstrated that unidirectional radiation characteristic can be obtained due to the combination of loop and dipole.2. On the basis of the former loop-dipole combined antenna, a human body model is built and an on-phantom antenna is simulated by using CST. Its performance is optimized by using the CST and parameter analysis. According to the simulation results, a real object is created. The measured results agree well with the simulated ones.3. Under the condition of keeping the antenna’s radiation properties unchanged, the minimalization of antenna is realized by the way of changing the configuration of the asymmetric dipole and the loop. Compared to the previous design, better directional radiation characteristics can be achieved.