Research And Design Of Low Profile Reconfigurable Metasurface Antenna

In recent years,with the integration and development of 5G communication and satellite communication,the density of space satellites is increasing.The increase in the number of satellites has led to a shortage of space orbit and spectrum resources.Reconfigurable antennas with dynamic frequency allocation and flexible regulation of electromagnetic waves can solve this problem well.Therefore,this thesis focuses on the design of reconfigurable antenna.It is proposed a planar microstrip antenna as the feed source to reduce the profile,and utilize the active metasurface to realize the frequency reconfigurable,multi-beam and beam scanning.The main contents are as follows.1.Research and design of low-profile frequency reconfigurable metasurface antenna.The frequency reconfigurable principle of Artificial Magnetic Conductor（AMC）loaded varactor diodes is studied,and a low-profile,multi-band reconfigurable antenna is designed by using the in-phase reflection property of AMC as the ground of antenna.It is shown that the distance between AMC and antenna is only 8mm（0.07λ₀）,the tunable bandwidth is1.64GHz-4.16GHz（88.2%）,and the peak gain reaches 10.65d Bi,which increases the bandwidth by 47%,and the gain by 5.65d Bi compared with the unloaded metasurface.2.Research and design of beam-steerable antenna with transmissive and reflective metasurface.Based on the amplitude modulation,the principle of the metasurface antenna loaded with PIN diodes to achieve beam scanning is studied.According to the principle,combining the metasurface and the wide-beam antenna,two pairs of low-profile and beam-scanning metasurface antennas are designed.It shows that the transmissive metasurface antenna achieves beam scanning at the angle of±97°in the H-plane at 3.5GHz and the peak gain of 6.81d Bi;the reflective metasurface antenna achieves beam-scanning of±45°at2.6GHz with a gain of 10d Bi,and the bias network has less influence on the antenna radiation.3.Research and design of high-gain,multifunctional beam controlling metasurface antenna.Based on the Generalized Snell’s Law,a 1bit reflective metasurface unit with 180°phase difference is designed,and based on the principle of reflective beam modulation,the coding scheme of the metasurface is proposed.The state of each PIN diode is controlled in real-time by the MCU development board to realize the arbitrary modulation of the beam.Based on the lens theory,a frequency selective surface with high transmittance is proposed to make up for the fault of the antenna’s gain.The simulated and measured results show that the distance between the antenna and the metasurface is only 5mm（0.06λ₀）,the multi-beam and two-dimensional beam scanning is realized in 3.45GHz-3.54GHz;after loading the lens,the gain of the antenna is improved by 4.6dBi.