EBG enhanced reflector feeds for wide angle scanning applications
This work is an extension of a series of works on the use of dielectric super-layers to shape the radiation pattern of each feed composing a focal plane imaging array. Using dielectric super-layers, the spill over from the reflectors are reduced without increasing the dimensions of each aperture. These effects are achieved when the inter-element distance between the feeds is large (2.4 wavelengths) which is typical for satellite based multi beam telecommunication applications. The shaping of the pattern is obtained with the excitation of a pair (TE/TM) of leaky waves, that radiate incrementally as they propagate between the ground plane and the super-layer. The super-layer can be realized with single dense dielectric slab ( epsivr=20.25) a double dielectric slab (epsivr=4.5) or an equivalent frequency selective surface. The maximum edge of coverage enhancement, with respect to reference free space configurations, that can be obtained in the different cases is equivalent. However the bandwidth over which the enhancement is maintained depends on how the super-layer is realized. The calculated embedded patterns provide an increase of the edge of coverage gain, with respect to the free space case, of at least 1.5 dB in an operating bandwidth of 3%. During the oral presentation the hardware manufactured to implement the previous concepts, including the filters for the frequency and reuse scheme, will be shown. Also the measured results will be compared with the simulations.