Researches Of Reflectarray Antenna On Millimeter Wave

Compared with microwave, millimeter wave has wider frequency band, higher accuracy and better resolution. In the meantime, millimeter wave has better penetration than infrared and can operate under different weather conditions. Microstrip reflectarray antenna has the advantages of high gain, light weight, small volume, low cost, easy processing. Moreover, it has no complicated feed network and has high design flexibility, which makes the reflectarray antenna been paid more and more attention in recent years. Combined with the advantages of millimeter wave and microstrip reflectarray, the research on millimeter wave microstrip reflectarray antenna is of great significance. Using the simultaneous beam-comparing method, monopulse comparator has the advantages of fast tracking speed, high tracking precision and strong anti-interference ability. Cassegrain antenna is a dual reflector structure, which can reduce the longitudinal dimension of reflector antenna and make the antenna become more compact. And the antenna is characterized by high gain, narrow beam and low side lobe. The dual band antenna has the advantage of working in dual-band with a common aperture. Thus it is of great significance to study the application of millimeter wave reflectarray in these areas. This paper mainly focuses on the microstrip reflectarray antenna element and array of millimeter wave, as well as the applications in monopulse cassegrain antenna and dual band antenna.At first, the working principle of microstrip antenna and the needed theoretical basis of designing reflectarray antenna are described in this paper. Then based on the detailed discussion on the bandwidth of microstrip reflectarray and the methods of improving the bandwidth of microstrip array, a millimeter wave single layer ring round mixed double resonance structure element is designed. And after that based on this element, a 50 by 50 W band reflectarray antenna has been designed. The microstrip reflectarray antenna is characterized by high gain and wide bandwidth. Finally the antenna is simulated and tested, and the results prove that the design is correct and effective.As the traditional monopulse Cassegrain antenna has the advantage of compact structure and the disadvantage of bulky and mass, a W band millimeter wave monopulse similar-Cassegrain reflectarray antenna is designed by using a portable microstrip reflectarray instead of the main reflector surface. As well as the antenna is manufactured and tested, performance is comparable to that of the traditional Cassegrain antenna.This paper applies millimeter wave microstrip reflectarray to dual band antenna, a Ka band two-dipole structure element and a W band structure element composed of a new type of weight structure element and a circular structure element are designed firstly. Then in order to reduce the mutual influence between the high frequency and low frequency array elements, this paper adopts a design idea of different band using different polarization. Based on this technique, a millimeter wave dual band reflectarray antenna is designed. The simulation results show that this idea and the design method are correct. Finally, a millimeter wave dual band similar-Cassegrain reflectarray antenna is designed by applying this dual band structure to the Cassegrain antenna. The results verify the effectiveness of the proposed design.