Antenna Reflector basics and types-Plane,Corner,Parabolic
This page on Antenna reflector basics and types cover different reflector antennas viz. plane reflector, corner reflector and parabolic reflector. The equations of these reflector antennas are also mentioned.
Plane Reflector Antenna
The figure-1 depicts plane reflector antenna type. It consists of primary antenna and reflecting surface. With this arrangement, it is useful to radiate EM energy in the desired direction but not possible to collimate energy in forward direction.
Following parameters depend on position of primary antenna and its polarization in the plane reflector antenna:
• Radiation Pattern
Corner Reflector Antenna
The figure-2 depicts corner reflector antenna type. It consists of two or three mutually intersecting conducting flat surfaces. In this type, feed element can be either dipole or array of collinear dipoles. Dihedral form is most popular in this type of antenna reflector. Trihedral forms with mutually perpendicular surfaces are used for radar target application.
The corner reflector antenna type is used to achieve collimation of EM energy in forward direction. It is used to suppress radiation in the backward and in the side directions.
Parabolic Reflector Antenna
The figure-3 depicts parabolic reflector antenna. This type of antenna has shape of paraboloid and hence it has properties of a parabola. The various feed antennas are used at focal point. Figure shows horn antenna at feed point.
Let us understand operation of the parabolic reflector antenna. As shown waves generated by horn antenna are incident on reflector. The reflector reflects them back which forms plane wavefront. The radiation is concentrated along the parabola axis. The waves are cancelled in other directions due to path as well as phase differences. This way parabolic reflector antenna converts spherical wave into plane wave.
Parabolic reflector is further categorized into following types based on reflector plate:
• Parabolic cylinder reflector• Cut or truncated parabolic reflector • Pill box or cheese antenna reflector • Torus antenna reflector • Offset parabolic reflector antenna.
Feeding for this type of reflector antenna is done using any of the following :
• Half wave Dipole
• Array of collinear dipoles
• Yagi-Uda antenna
• Horn antenna
• Cassegrain feed
Advantages: Small size and low cost.
Disadvantages: The presence of side lobes here create EMI. The effect of EMI is more dominant in low noise receivers due to imperfections in the reflector. This is the disadvantages of this type of antenna.
Antenna related links
Table of Antenna types and gain equations.
Manufacturers of RF antenna
Set Top Box manufacturers
Set Top Box basics
TV Antenna Booster
Satellite Dish Antenna