Design Of Multi-Linear Polarization Reconfigurable Antenna And Array

Polarization is an important performance indicator of antennas.If an antenna receives a wave that is different from its polarization direction,the polarization mismatch will occur,resulting in power loss.For example,if a left-handed circularly polarized antenna receives a right-handed circularly polarized component in a incoming wave,it will be completely mismatched.Conversely,a right-handed circularly polarized antenna will also be unable to accept the left-handed circularly polarized component in the incoming wave.The linearly polarized antenna cannot accept the linear polarization component of the incoming wave perpendicular to its polarization direction,that is,the antenna cannot accept the polarization component completely orthogonal to it,but can accept the non-orthogonal polarization component,but will lose power.In order to receive arbitrary polarized waves,the conventional solution is using a circularly polarized antenna or an orthogonal linearly polarized antenna.However,although a circularly polarized antenna can receive any linearly polarized wave,it is always accompanied by a maximum energy loss of 50%.On the other hand,due to the small number of linear polarization states,orthogonal linear polarization reconfigurable antennas cannot fully overcome the polarization mismatch problem.In order to improve polarization efficiency,a multi-linear polarization reconfigurable antenna is the best candidate antenna for receiving a random polarization signal.At the same time,in modern wireless communication,the provision of a wideband antenna with simple structure for mobile devices and advanced devices has also been widely researched.Adding polarization to this higher degree of freedom in array synthesis can greatly reduce the polarization mismatch loss of this vector field synthesis and achieve spectrum multiplexing.The main work of this paper is to design a wideband multi-linear polarization reconfigurable antenna which can realize 16 switchable linear polarization states;and another simple structure of multi-linear polarization reconfigurable antenna as unit antenna,a binary coded genetic algorithm is used to optimize the array pattern with low sidelobe level and low cross polarization level.Firstly,this paper introduces some polarization reconfigurable antennas,as well as the research background domestic and abroad,and briefly summarizes the related literature of polarization reconfigurable antennas.Then,it makes a theoretical analysis of polarization reconfigurable antennas,introduces the limitations of circular polarized antennas and orthogonal linear polarized antennas,and the advantages of multi-linear polarization reconfigurable antennas.Secondly,a wideband multi-linear polarization reconfigurable antenna facilitated by L probes is proposed.The antenna uses L-shaped probe feeding structure and center feeding circular patch groove structure to realize wideband antennas with 16 switchable linear polarization states.From 0 degrees to 337.5 degrees,there are 32 working states at a 11.25 degrees interval,but there are only 16 polarization states from 0 degrees to 168.75 degrees at a 11.25 degrees interval,and the other 16 coincide with these.The simulated and measured results show that the polarization reconfigurable antenna has good performance.Then,an improved pattern extraction method and an optimization method based on binary coded genetic algorithm are proposed for multi-linear polarization reconfigurable antenna array,which reduces the complexity and workload of pattern extraction and keeps the accuracy of the results.Finally,a simple multi-linear polarization reconfigurable antenna is designed and applied to the synthesis of 16-element linear-polarized reconfigurable linear antenna array.In the synthesis,the improved binary coded genetic algorithm is used to select the appropriate polarization state for each polarization reconfigurable element,which makes the array pattern have lower sidelobe level and cross-polarization level.The results of HFSS full-wave simulation verify the feasibility and validity of the synthesis method.Multi-linear polarization reconfigurable antennas and arrays are widely used in practical applications,especially in detection,wireless biomedical systems and conformal antenna arrays.It cannot only avoid the complexity of feeding network caused by traditional array amplitude modulation,but also make the array have the ability to adjust polarization,improve the stability of transmission channel and resist external interference.