The Research And Design Of Two Wearable Antennas

In recent years, with the development of wireless communication technology, body area network as a new form of networks is being studied and has achieved a certain development, and in order to realize the communication of the body area network, the wearable antenna plays an important role in it. Generally speaking, the wearable antenna is a type of antennas which can be integrated into clothes, and has a low profile, easy to carry and conformal with body and other characteristics. The prospect of wearable antenna is worth to expect. In medical field, military field, sports field and other areas, it will demonstrate the tremendous value.The wearable antenna is embedded in clothing, and will radiate to the carrier, so compared to the general antenna, not only the various parameters of wearable antenna should be ensured, but the received radiation of antenna carrier must be in the range of security. Moreover, the performance of the antenna under deformation is very worth of attention. The author takes part in the project "The Research of Wearable Antenna" that Liaoning Putian Digital Company cooperated with Dalian Maritime University Antenna and Microwave Institute, the finished main works of this paper are as follows:(1) The nickel-copper woven cloth which has the good conductive property is chosen as the radiation unit, and the substrate layer is felt whose thickness is2mm. The author chooses the cavity perturbation method after comprehensive comparison of various methods to measure the relative permittivity and loss tangent.(2) A right-handed circular polarization miniaturization wearable antenna which works at the1.575GHz frequency is designed and realized. The performance parameters of the antenna are analyzed when the antenna is at the bent state and is placed at different distances from human body. The specific absorption rate is simulated and researched in order to show the influence that the antenna radiation on the human body.(3) A dual-band wearable antenna which works at the2.45GHz and5.2GHz center frequencies is designed and realized. The coplanar waveguide fed method without the ground plane is used to achieve the good matching. The changes of parameters are analyzed when the antenna is at different states including bent and being placed at near the human body. However, the radiation on human body is large and in order to reduce specific absorption rate, a dual-band electromagnetic band-gap structure is designed for this wearable antenna, not only the radiation on body is reduced and the gain of the antenna can be increased.(4) The reflection coefficient, axial ratio and radiation pattern of two kinds of antennas are measured in microwave darkroom when the antennas are flat and bent. It turns that the results meet the requirements in different conditions except axial ratio deteriorates of the antenna works at1.575GHz.