| The application of wearable devices has gradually stepped into our daily lives,but there is a multipath fading effect when wearable devices communicate,and polarization diversity technology is a means to improve the multipath fading effect.Based on this,this article explores and proposes for the first time the application of polarization diversity antennas to wearable antennas,and researches on all-fabric polarization diversity antennas based on microstrip antennas and microstrip slot antennas.The specific research content is as follows:1.Research on all-fabric microstrip polarization diversity antenna.The antenna adopts the conventional patch antenna design method to set the patch as a square patch,uses a microstrip line structure to feed it at the middle of the adjacent two sides of the patch,and uses a quarter-wavelength impedance converter technology to obtain good results match.Here,the patch layer and ground layer of the antenna are made of metal conductive fabric,and the dielectric substrate layer is 100% cotton fabric.The thickness of the pure cotton fabric is 1.50 mm,and the dielectric constant measured by the resonance method is 1.82.The simulation and test results in the flat state are in good agreement,and the results show that the resonant frequency of the antenna is about 5.8GHz,and the antenna has an isolation below-20 d B in the bandwidth range.2.Research on all-fabric microstrip slot polarization diversity antenna.In order to further increase the isolation and bandwidth,this paper studies the polarization diversity antenna based on the microstrip slot.The antenna is an isosceles trapezoidal slot antenna with a simple planar structure.The microstrip line structure is used on the adjacent two sides of the patch.To feed power,the ground and the substrate are both rectangular,and the ground has an isosceles trapezoidal slot.The antenna uses the isosceles trapezoidal slot to radiate so that it can realize two orthogonal polarization modes.The resonance frequency is 5.8GHz.The simulation and test results under the flat antenna state are in good agreement,the dual-port isolation is lower than-25 d B in the working frequency band,and the bandwidth is greater than 1GHz.3.Research on all-fabric microstrip polygonal slot polarization diversity antenna.Due to the characteristics of the electrical parameters of the human body at different frequencies,this paper studies the polarization diversity antenna with a resonance frequency of 2.45 GHz.The antenna ground and substrate are both rectangular,with a dodecagonal slot on the ground,and the uppermost feeding part is composed of two opposing microstrip lines placed on the slot.The two microstrip lines are respectively.It is a zigzag microstrip line and a stepped impedance gradient line.The resonant frequency of the antenna is set to 2.45 GHz.The antenna uses a regular dodecagonal slot to radiate,so that the antenna can support two mutually orthogonal polarization modes.This article also tested and analyzed the antenna performance under conformal and wrinkled conditions,and summarized the rules.Finally,the antenna parameters under the simple three-layer solid-state human body model are simulated and analyzed. |
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