| A circularly polarized antenna with broadband performance and a polarized reconfigurable rectangular microstrip patch antenna are proposed.First,a circularly polarized rectangular patch antenna with broadband characteristics is introduced.The antenna is an improved structure of the E-shaped patch antenna,and its circular polarization characteristic is realized by two unequal parallel grooves of the E-shaped patch.Thus,by introducing asymmetry,two orthogonal currents are excited on the patch and a circularly polarized field is achieved.With the aid of HFSS simulation,the influence of the antenna electrical parameters was analyzed by optimizing the antenna structure size.Based on these studies,the design process of circularly polarized E-shaped patches was summarized.Compared with the circularly polarized U-groove patch antenna proposed in the literature,the reflection coefficient,axial ratio,radiation pattern and antenna gain are simulated and analyzed.Secondly,a polarization reconfigurable single-feed E-shaped patch antenna with broadband performance is proposed.With the aid of two RF PIN diodes as switches,the antenna can be switched from right-hand circular polarization(RHCP)to left-hand circular polarization(LHCP)and vice versa.The structure of the antenna consists of a single-feed E-shaped patch and an RF switch,each slot optimized to determine its position.If one of the switches is on and the other is off,the two slot lengths will become valid and unequal,and circular polarization will be obtained.If the states of the two switches are reversed,reverse circular polarization will be obtained in the same frequency band,thereby achieving polarization reconfigurability.Finally,simulation analysis was performed using software HFSS,and the reflection coefficient,axial ratio,radiation pattern and antenna gain were given. |
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