Electro-Magnetic Band-Gap feed overlapping apertures for multi-beam antennas on communication satellites

Dual‐polarized planar lens antenna designed with a quad‐ridged frequency selective surface

“…These aspects are specially important in multiple‐spot beam systems, where no less than four reflectors and a feed per beam are currently implemented . Several solutions have been proposed to reduce the number of reflectors in these systems, for example, a circular polarization selective surface at the focus of the reflector to combine two different polarizations in a single reflector, or an electromagnetic band‐gap structure to generate overlapped beams at the focus of the reflector …”

“…6 Several solutions have been proposed to reduce the number of reflectors in these systems, for example, a circular polarization selective surface at the focus of the reflector to combine two different polarizations in a single reflector, 7 or an electromagnetic band-gap structure to generate overlapped beams at the focus of the reflector. 8 This paper proposes an alternative solution based on the use of an FSS working as a microwave planar lens. This operation is similar to the one presented by the so-called transmitarray antennas, [9][10][11] in which the phase profile given by the feeder, placed at a medium-long distance (typically F/D ≈0.85), is properly flattened.…”

Microwave Planar Lens Antenna Designed With a Three-Layer Frequency-Selective Surface

“…A simple FSS is the so-called metallic hole array, whose unit cell is a perforated metallic sheet. This kind of FSS has been recently used to enhance the directivity of a circular aperture in the X-band [5], or to design a multiple-beam antenna in the Ka-band [6]. These proposals present good performance, but they suffer from narrow bandwidth, caused by the use of electrically-small unit cells to form the FSS.…”

Diseño de lentes metálicas usando la teoría de modos característicos.

“…En losúltimos años, ha habido un intento de encontrar nuevos materiales con propiedades electromagnéticas que no pueden ser encontradas en la naturaleza [70]. Bajo la denominación de metamateriales se engloban conceptos ya conocidos como estructuras periódicas [71], dieléctricos artificiales, estructuras EBG [72], superficies polarizadoras [73] y superficies selectivas en frecuencia (FSS). En la presente tesis se plantea como objetivo utilizar superficies metálicas como elementos de cambio de fase de las ondas incidentes, dependiendo de la impedancia equivalente de la superficie difractante.…”