Research On S-Band Reconfigurable Antenna Based On Bistable Material

Reconfigurable antennas have been studied for use in wireless communication systems,satellite communication systems,and radar systems for radio frequency(RF)devices due to their versatility.Two polarization reconfigurable antennas based on bistable materials are designed in this paper.The two steady states of the first antenna are a Vivaldi antenna in a linearly polarized state and a four-arm helical antenna in a circularly polarized state.The designed dual-polarized antenna based on bistable material is divided into two parts,namely the radiating structure part of the antenna and the metal reflecting plate.The substrate of the antenna is a bistable asymmetric glass fiber reinforced plastic(GFPS)composite laminate having a relative dielectric constant of 4.9 and a thickness of 1.2 mm.The radiating structure of the antenna: the front side comprises a metal strip with an inclined angle,the uniform distribution length thereof is sequentially decreased,the metal strip with the same inclination angle,and the back side comprises a rectangular metal patch for adjusting the impedance matching and optimizing the partial frequency band.Impedance matching.The metal reflector is a circular metal plate.The dielectric plate is placed perpendicular to the metal reflector.The antenna is fed by a 50 ? coaxial line.The bistable material-based dual-polarized antenna has a linear polarization state with an operating bandwidth of 50%(2.4-4.0 GHz),a gain of more than 5.5 dBi,a front-to-back ratio of greater than 8 dB,and a frequency range of 2.4-3.4 GHz.The front-to-back ratio is greater than 10 dB.The circularly polarized state has a working bandwidth of 48.3%(2.2 to 3.6 GHz),a gain greater than 6.5 dBi,a front-to-back ratio greater than 8 dB,and a front-to-back ratio greater than 10 dB in the 2.3-3.6 GHz band.The two steady states of the second antenna are left-handed circular polarization and right-handed circular polarization,respectively.The structure of the antenna is similar to that of the first type of antenna.The m ain radiating elements of the antenna are distributed on a bistable asymmetric glass fiber reinforced polymer composite laminate having a relative dielectric constant of 4.9 and a thickness of 1.2 mm.When the antenna is deployed,similar to the Vivaldi antenna,two polarization-inverted polarization states are formed by two different curling steady states,and the metal reflector is a circular metal plate.The antenna is fed by a 50 ? coaxial line.The bistable material-based dual-polarized antenna has a left-hand circular polarization state with a reflection coefficient of less than-10 dB and a relative impedance bandwidth of 98%(1.67-4.88 GHz),and an axial ratio of 1.7-2.3 GHz and 2.6-3.8 GHz.Less than 3 dB in the frequency range.The gain is above 6.5 dBi over a 3 dB axial ratio bandwidth.The right-hand circular polarization state has a relative impedance bandwidth of less than-9.5 dB of 64%(2.27-4.43 GHz)and an axial ratio of less than 3 dB over the frequency range of 2.2-3.1 GHz.Within a 3 dB axial ratio bandwidth,the gain is greater than 7.7 dBi and the maximum gain is 9.8 dBi.The above dual-polarized antennas based on bistable materials are optimized by CST Microwave Studio? electromagnetic simulation software.