MEMS-based Switches Reconfigurable Frequency Selective Surface Active Research And Design

Frequency selective surface (FSS) is a two-dimensional periodic array structure, its essence is an electromagnetic space filter, FSS and electromagnetic wave in interactions could show band-pass or resistance of the electromagnetic wave transmission characteristics obviously. FSS is widely used in the microwave, infrared and visible band. And due to its unique electrical characteristics, it is not only applied in the field of satellite communications, but also plays an important role in the development of stealth technology. For the classic passive frequency selective surfaces, its electrical characteristics cannot be changed after processing, so that it cannot quickly adapt to changing electromagnetic environment. The filter characteristics of active reconfigurable frequency selective surfaces can be controlled by external incentives, so it can adapt well to changes in the complex electromagnetic environment, and it will become a national research trends in frequency selective surface.Firstly, this paper studied the basic concepts of frequency selective surfaces and working principle, and introduced the classification and characteristics of frequency selective surfaces, and analyzed the impact of the structure, cell size, cell spacing, dielectric materials, the angle of incidence and polarization on the resonance characteristics, and described characteristics of frequency selective surface grating lobe and its impact.Secondly, this paper briefly described the RF MEMS switches, and analyzed the working principle, technical specifications, and general production process, and designed a RF MEMS switch for active reconfigurable frequency selective surfaces.After that, this paper designed a reconfigurable active X-band frequency selective surface. This FSS could stable change the central frequency by1GHz instantaneous bandwidth in the X-band8-9GHz,9-10GHz,10-11GHz,11-12GHz, and pass through the waves with a rate of>85%, incidence angle range0°-45°, band rejection is10dB@(1-6GHz),12dB@(14-18GHz). Based on this design specifications, this paper presents two different designs. One solution is that using the permutations of one band-pass frequency selective surface and three band-stop frequency selective surface to form a stable1GHz passband transition. In this program, a new formula with an8-12GHz band frequency selective surface and three X-band bandwidth of1GHz band miniaturized band-stop frequency selective surface are first designed, and finally with the RF MEMS switchers added to band-stop frequency selective surfaces, it will form the active reconfigurable frequency selective surface control by an external excitation to control the transition of stopband stable; The second program is to use the characteristics of band-pass frequency selective surfaces directly. In this program, firstly X-band frequency selective surfaces with1GHz bandwidth are designed, and on this basis, the RF MEMS switchers are added in it, so that it can form stable transition in X-band.Finally, compared by the first active reconfigurable frequency selective surface, I chose the second band-pass transition type active reconfigurable frequency selective surface. After production and processing, it showed that the design of the product had the good performance and met the requirements.