Reflecto-Transmittive Antenna using Active Frequency Selective Surfaces

摘要

A novel reflecto-transmittive antenna is presented using active frequency selective surface (AFSS). The reflecto-transmittive screens are shaped resembling to parabolic reflector. The structure consists of an AFSS array, and a patch antenna used a feed. Each element in the array contains of two rectangular shaped patches connected with each other by a high-frequency pin-diode. By switching the diode between ON and OFF states, the reflection and transmission characteristics of the element are controlled. Three AFSS panels are used to investigate the potential of the antenna in reflecting and transmitting the radiation beams. To shape the proposed antenna with parabolic reflector, two panels beside the central are rotated to various angles. The proposed antenna results in maximum directivity of 11.9 dBi for ON state (reflection), while a 7.8 dBi for OFF state (transmission). The maximum directivity is achieved when 15 ô rotation angle is applied to side AFSS panels towards the feed. The antenna performance is evaluated at 2.45 GHz. The performance of the proposed antenna is compared with an antenna designed with PEC in the same environment. The obtained results show a good agreement.