| As the aging of the social population,Wireless body aera network(WBAN)will be widely used in the medical field.Wearable antenna is an important component in ensuring the reliability and stability of wireless communication,which is of great research significance.Due to the electrical characteristics of human body,the design of wearable antenna is challenging.The substrate integrated waveguide(SIW),is particularly suitable because of its simple structure and excellent electromagnetic shielding performance.In addition,the SIW structure is very perfect for the implementation on wearable textile,which can maintain human comfort while providing stable and efficient performance.This dissertation was supported in part by the National Natural Science Foundation of China(61372008),and in part by the Science and Technology Planning Projects of Guangdong Province(2014A010103014,2015B010101006),the following works are carried out mainly about wearable textile antennas based on SIW technology.(1)Wideband SIW textile antenna for WBAN applications.For the previous wearable SIW textile antennas have the drawbacks of single resonant mode and narrow impedance bandwidth,this part of works proposes a simple broadband SIW textile antenna for 5-GHz WBAN applications.The dimensions of the proposed antenna are 42×42×2 mm~3 and the proposed antenna is made of wool felt,conductive fabric and brass eyelets.By using the coupling between two half-mode cavities,broadband impedance bandwidth is achieved.The measured impedance bandwidth of the proposed antenna is 21.8%(5.06–6.26 GHz),the measured gain is 6.0 d Bi,and the average radiation efficiency is 54.5%.In wireless communications,it is necessary to miniature the size of antennas due to the limitation of installation space.(2)Compact dual-band wearable textile antenna based on quarter mode SIW.This part of the works is mainly to address the issues of larger size of the previous antenna.Using the characteristics of SIW cavity electric field distribution,after the square SIW resonant cavity is separated twice,the quarter mode SIW cavity is obtained,and the electric field distribution remains unchanged,which greatly reduces the size of the antenna.The size of the antenna patch is 36.8×36.8 mm~2,and the felt material,with a dielectric constant of 1.2 and a loss tangent of0.02 is used as substrate.The proposed antenna works in the 3.5-GHz Wi MAX band and the5.8-GHz ISM band.The measured impedance bandwidths of the antenna are 3.4%(3.44–3.56GHz)and 3.5%(5.72–5.92 GHz).The dual-band operation can be adjusted independently according to the electric field distribution.The measured results of the antenna agree well with the simulated ones.The antenna mechanism is analyzed through the antenna evolution,and the influences of relevant parameters on the antenna performance are studied.(3)Compact wearable SIW textile antenna based on CRLH structure.Although the quarter mode SIW can effectively miniaturize the size of the antenna,it is at the expense of the cross-polarization ratio of the antenna radiation pattern.This part of the works proposes a compact wearable SIW antenna based on composite right/left hand(CRLH)structure.CRLH is a metamaterial that is achieved by etching interdigital slot in SIW cavity.The interdigital slot behaves as a series capacitor as well as a radiator,and the metallic vias introduces equivalent parallel inductance,so that the antenna has the characteristics of CRLH.Utilizing the zero-order resonance characteristics of CRLH,the antenna operates below the cut-off frequency,and the miniaturization is realized.The dimensions of the antenna areπ×16×16×2 mm~3,and it operates in the 5.8-GHz ISM band.The measured impedance bandwidth of the antenna is 5.5%(5.62–5.94 GHz),the measured gain is 4.6 d Bi,and the radiation efficiency is 60.5%.In this dissertation,three wearable textile antennas based on SIW technology are proposed to provide technical solutions for wearable antenna design applied to WBAN. |
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