Category: ANTENNAS

Wideband Antenna Types

Wideband Antenna Types: It is often desirable to have an antenna capable of operating over a wide frequency range. This may occur because a number of widely spaced channels are used, as in short-wave transmission or reception, or because only one channel is used (but it is wide), as in television transmission and reception. In […]

Lens Antenna Design

Lens Antenna Design: The paraboloid reflector is one example of how optical principles may be applied to microwave antennas, and the Lens Antenna Design is yet another. It is used as a collimator at frequencies well in excess of 3 GHz and works in the same way as a glass lens used in optics. Principles: […]

Horn Antenna Design

Horn Antenna Design: Horn Antenna Design – As we know, a waveguide is capable of radiating energy into open space if it is suitably excited at one end and open at the other. This radiation is much greater than that obtained from the two-wire transmission line described at the beginning of this chapter, but it […]

Parabolic Antenna

Parabolic Antenna: The Parabolic Antenna is a plane curve, defined as the locus of a point which moves so that its distance from another point (called the focus) plus its distance from a straight line (directrix) is constant. These geometric properties yield an excellent microwave or light reflector, as will be seen. Geometry of the […]

Directional High Frequency Antenna

Directional High Frequency Antenna: Directional High Frequency Antenna are likely to differ from lower-frequency ones for two reasons. These are the HF transmission/reception requirements and the ability to meet them. Since much of HF communication is likely to be point-to-point, the requirement is for fairly concentrated beams instead of omnidirectional radiation. Such radiation patterns are […]

Antenna Coupling

Antenna Coupling: Antenna Coupling : Low and medium frequency antennas are the ones least likely to be of resonant effective height and are therefore the least likely to have purely resistive input impedances. This precludes the connection of such an antenna directly, or via transmission line, to the output tank circuit of a transmitter. Some […]