what is an antenna

The study of antennas is very extensive and would need several texts to cover
adequately. In this chapter, however, a brief description of relevant performances and
design parameters will be given for introductory purposes.
An antenna is a component that radiates and receives the RF or microwave power.
It is a reciprocal device, and the same antenna can serve as a receiving or
transmitting device. Antennas are structures that provide transitions between
guided and free-space waves. Guided waves are confined to the boundaries of a
transmission line to transport signals from one point to another [1], while free-space
waves radiate unbounded. A transmission line is designed to have very little
radiation loss, while the antenna is designed to have maximum radiation. The
radiation occurs due to discontinuities (which cause the perturbation of fields or
currents), unbalanced currents, and so on.
The antenna is a key component in any wireless system, The
RF=microwave signal is transmitted to free space through the antenna. The signal
propagates in space, and a small portion is picked up by a receiving antenna. The
signal will then be amplified, downconverted, and processed to recover the

Re: what is an antenna

classification of antenna
1. Shapes or geometries:
a. Wire antennas: dipole, loop, helix
b. Aperture antennas: horn, slot
c. Printed antennas: patch, printed dipole, spiral

2. Gain:
a. High gain: dish
b. Medium gain: horn
c. Low gain: dipole, loop, slot, patch

3. Beam shapes:
a. Omnidirectional: dipole
b. Pencil beam: dish
c. Fan beam: array

4. Bandwidth:
a. Wide band: log, spiral, helix
b. Narrow band: patch, slot

Re: what is an antenna

AntennaA conductive device designed to radiate RF (Radio Frequency – Also, see Radio Wave ) energy from a wireless transmitter , or to capture RF energy for application to a wireless receiver. Antennas come in many shapes, sizes and configurations. Some are omni directional while others have different directional polar patterns .