| At present,the development of wireless communication technology has entered a new stage.With the rapid rise of mobile communication and biosensor technology,a short-range wireless communication technology,wireless body area network,has come into the public eye.Because UWB antenna has the remarkable characteristics of high speed,low power consumption,wide bandwidth and many other traditional wireless communication technologies do not have,this paper puts forward the research idea of combining UWB antenna with wireless body area network,which is of great significance to the development and popularization of wireless body area network technology in the future.With the development of wireless communication technology,the narrow-band communication systems are also increasing,and the spectrum resources become extremely scarce.If we want to avoid mutual interference between wireless communication systems,we need to design a variety of notch structures for UWB antenna,so as to ensure that the antenna performance will not be affected by narrowband signals.The main work and research results are as follows:A wearable ultra wideband antenna for wireless body area network system is designed by HFSS electromagnetic simulation software.The antenna is based on flexible circuit board printing process and fed by coplanar waveguide,so that the antenna can meet the wearable design requirements while having stable impedance matching bandwidth.The simulation results show that the working frequency range of the antenna covers 9.1GHz bandwidth from2.9GHz to 12.0GHz At the same time,the radiation pattern analysis shows that the antenna can maintain a high radiation gain at the corresponding frequency point and present omnidirectional radiation characteristics.The designed wearable UWB antenna dielectric substrate is made of polyimide flexible material.Because of its special material,the bending deformation characteristics of the antenna are analyzed to make it conform to the characteristics of conformal with the human body and meet the requirements of wearable applications.The simulation results show that the antenna can keep the working bandwidth stable in the UWB antenna frequency band under any bending conditions,At the same time,the simulation experiment of wearable antenna in human environment is deeply restored.By loading metal shielding layer on the antenna,the backward radiation is suppressed,so as to effectively reduce the electromagnetic radiation generated by the antenna to the human body,and improve the forward radiation gain of the antenna at the same time,so as to realize the transformation from omni-directional antenna to directional antenna.In order to avoid the influence of Wi MAX,WLAN and satellite X-band communication systems on the performance of the designed wearable UWB antenna due to the overlap of some narrow-band communication systems and UWB antennas,a complementary resonant ring slot is opened in the center of the radiation patch,so that the antenna can operate at3.32GHz?3.74 GHz and 4.99GHz?6.02 GHz.The antenna can also generate notches in the frequency band of 7.21GHz?8.62 GHz by opening an inverted "U" slot on the microstrip line fed by coplanar waveguide.Through the analysis of electromagnetic simulation and experimental results,the above frequency bands all cover the working frequency band of the narrowband communication system that needs to be shielded,so the designed antenna has obvious triple notch characteristics.At the same time,by observing the radiation pattern of the antenna at the center frequency point of the above notch band,it can be seen that the radiation gain of the antenna will be affected by the loading notch structure,so it can meet the design requirements. |
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