Research And Application Study Of Wearable Antennas And Liquid Antennas

Currently,internet of thing(IoT)is attracting more and more attention,which has been regarded as a potential technique that will benefit the industry and economy,as well as individuals' daily life.As part of the IoT,the body-centric wireless network plays a significant role in the future communication.With the widespread of small portable wearable devices,the body-centric wireless network is feasible for the commercial and military applications.As essential components of the wearable devices,antennas are the dominant role to help realize the communication between each other.Therefore,study of wearable antennas in the body-centric wireless network is crucial for the future application of IoT.On the other hand,the increase demand of the wireless application and spectrums require that the electronic devices work in a dynamic frequency range.Especially,for the military application,radars or the communication systems need to change the working frequency irregularly so that to reduce the risk of detection,which requires that the antennas should be reconfigurable and of low radar cross-section scattering(RCS).Benefiting from the fluidity,flexibility,reconfigurability,low cost and low RCS,the liquid antenna can help solve the above problems,which is helpful for the marine wireless application and the navy communication.Focusing on wearable antennas and liquid antennas,the main work and innovations of this thesis are as follows:1.Based on the existing metal part of the wearable things,two wearable zipper antennas are proposed for body-centric wireless network.The first antenna is reformed from the metal zipper of the coat,while the second one is constructed by the modified zipper of the handbag.Simulations,analyses and measurements of both antennas were made to verify the feasibility.With low cost and compact installation,the wearable zipper antennas can be kept well in the daily life.By feeding the antennas in different positions or changing the pull state of the zipper,those two antennas can provide great flexible control for wearable applications.2.Modified by watch strap,the frame of glasses and the shoelaces,three wearable antennas were designed.Parametric study of strap antenna such as the strap width,the shape and the feeding positions were conducted to evaluate the performance,as well as installation places of antennas including the arm,the wrist and the palm.Regarding the glasses frame antenna,the frame shapes and parameter as well as the lens material were studied and analyzed.While for the shoelaces antennas,the radiation characteristics for different feeding positions and tightening levels were simulated and tested,which verified the feasibility of the shoe laying navigation and anti-collision.3.On the basis of the non-metallic liquid,two cavity liquid antennas were proposed,including a non-tunable single liquid material resonator antenna and a tunable liquid antenna with combination of two liquid materials.Both antennas were designed and simulated.The effects of liquid components,feeding position,probe length and other factors on the antenna performance were studied.By changing the composition of the liquid,the two liquid materials-based liquid technique provides a prospective view for the reconfigurable application for liquid antenna.4.Based on saline water,two reconfigurable helix antennas were realized by manually changing the amount of injected liquid.Influence of the probe parameter and brine concentration on the antennas performance was made in the simulations and measurements.The results showed that both two liquid helical antennas were feasible for the reconfigurable communication applications.