| A network-centric world with instantaneous,non-stop connectivity is highly desirable in both the military and the civilian consumer realm.There has been an increasing requirement for highly portable communications equipment,which are compact,lightweight and low profile,which has led to an interest in body-wearable antennas.The majority of open-source research papers have considered the use of bodywearable antennas for UWB networks.There are several challenges associated with devices that contain body-wearable antennas.The requirement for compact size and volumes,particularly with devices that are worn near the face and on limbs,present challenges with fabrication and performance.Since the human body contains a variety of dielectric variation and high losses are experienced for electromagnetic wave propagation across human tissues,a large reduction in antenna efficiency may be experienced.Planar antenna geometries are highly desirable for body wearable applications,as they exhibit extremely low profiles and are unobtrusive.This thesis present three ultra-wideband wearable antennas.The main contents of the thesis are as follows:(1)This study introduces the desirability of wearable antenna and the development of this technology.Possible body wearable antenna applications are presented.The processes related to conductive inkjet printing and applications and the theory of broadbandization and miniaturization of antennas are explored.(2)A wearable monopole antenna working in 30-88 MHz was designed and tested.First,the antenna structure is proposed,and then the transmission line transformer is used for impedance matching to realize the broadbandization of the antenna.Finally,the monopole antenna conformal to the helmet is processed and tested.The measurement shows that at 30-88 MHz,the antenna is omnidirectional in the horizontal direction,and the radiated energy towards the human body conforms to the international standard,which proves the feasibility of the design.(3)A microstrip monopole wearable antenna loaded with reflector is present.The traditional disc-cone antenna is planarized and projected,and a series of broadband and miniaturization are carried out to overcome the defect of the main radiator of the traditional structure,which greatly expands the bandwidth of the antenna and reduces the size of the antenna Finally,the antenna reflector improves the front-to-rear ratio of the antenna to meet the SAR requirements.The actual processing test verifies the robustness of the antenna.(4)This study designs a coplanar waveguide(CPW)monopole wearable antenna loaded with AMC.The application of new flexible materials in the field of wearable antennas was explored,the influence of loading AMC on the antenna radiation performance was compared,and the robustness and SAR of the antenna under human interaction with the antenna were analyzed. |
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