Research On THz Reflectarray Antenna

Pillbox antenna,which can be used for fast terahertz synthetic aperture imaging,has many advantages,including small size,simple manufacture process,low cost and fast beam scanning capability.At present,pillbox antenna usually uses a mechanical rotating sub-reflector to achieve one-dimensional beam scanning,and the scanning speed is limited by the rotating speed of the sub-reflector.In order to improve the beam scanning speed of the pillbox antenna,a novel reflectarray antenna based on pillbox structure is proposed in this paper.The parabolic reflector of the traditional pillbox antenna is replaced by a reconfigurable microstrip reflectarray.And electronically beam scanning of pillbox antenna is achieved,which is of great significance to improve the refresh rate of terahertz imaging.Specific works are as follows:1)The main structure of the pillbox antenna is designed,optimized,manufactured and tested,which will be used as the feed structure of the novel reflectarray antenna.2)Based on theoretical analysis of the microstrip circuit's phase characteristics,an aperture coupled microstrip reflectarray element is designed using appropriate PCB material.The reflectarray element,which is easy to integrate with microstrip phase shift circuit,has the advantages of low loss and large phase shift range.3)A novel fixed-beam reflectarray antenna based on pillbox structure is designed using the reflectarray element.The simulation results achieve 59.6% aperture efficiency and 9.3% relative bandwidth.4)The performance of microstrip phase shift circuit based on PIN diode is improved.Microstrip phase shift element is designed using the improved phase shift circuit,and 1-bit electronically controlled phase shift is implemented in 0.1THz band.5)A novel electronically beam scanning reflectarray antenna based on pillbox structure in 0.1THz band is designed using the electronically controlled microstrip phase shift element.The phase compensation of the array is optimized.Full-model simulation of the novel antenna achieves 30-degree one-dimensional beam scanning.