A single radiating element approximately 1/4 wavelength long. Directivity 2.2 dBi, 0 dBd.
Loaded 1/4 Wave
The loaded 1/4 wave antenna looks electrically like a 1/4 wave antenna but the loading allows the antenna to be physically smaller than a 1/4 wave antenna. Quite often this is implemented by placing a loading coil at the base of the antenna. Gain depends upon the amount of loading used. Directivity 2.2 dBi, 0 dBd.
A single radiating element 1/2 wavelength long. Directivity 3.8 dBi, 1.6 dBd. A special design is the end fed 1/2 wave.
A single radiating element 5/8 wavelength long. Directivity 5.2 dBi, 3.0 dBd.
Two or three radiating elements separated by phasing coils for increased gain. Four styles are common:
- 5/8 over 1/4: top element is 5/8 wave and bottom element is 1/4 wave. Directivity 5.4 dBi, 3.2 dBd.
- 5/8 over 1/2: top element is 5/8 wave and the bottom is 1/2 wave. Directivity 5.6 dBi, 3.4 dBd.
- 5/8 over 5/8 over 1/4: the top 2 elements are 5/8 wave and the bottom element is 1/4 wave. Directivity 7.2 dBi, 5.0 dBd.
- 5/8 over 5/8 over 1/2: the top 2 elements are 5/8 wave and the bottom element is 1/2 wave. Directivity 7.6 dBi, 5.4 dBd.
Please note the directivity is given above for common antenna configurations. The gain depends upon the electrical efficiency of the antenna. Here is where the real difference between antenna manufacturers is seen. If you cut corners in building an antenna, the gain may be significantly lower than the directivity. Larsen uses low-loss materials to minimize the difference between the gain and the directivity in our antennas.
The vertical portion of the antenna assembly acting as the radiator of the radio frequency.
An antenna - usually 1/2 wavelength long - split at the exact center for connection to a feed line. Dipoles are the most common wire antenna. Length is equal to 1/2 of the wavelength for the frequency of operation. Fed by coaxial cable.
These antennas are generally integrated on a base for applications such as access points. This structure could be externally mounted (ex: sleeve dipole) or directly integrated on the PC board of the system (ex: printed dipole).
A directional, gain antenna utilizing one or more parasitic elements. A yagi consists of a boom supporting a series of elements which are typically aluminum rods. Named after one of the Japanese inventors (Yagi and Uda).
Omni-ceiling mount antennas are used for the propagation of data in an in-building environment. In order to provide good coverage, these antennas are vertically polarized and present an omnidirectional pattern in the horizontal plane and a dipolar pattern in the vertical plane.
An antenna consisting of a parabolic reflector and a radiating or receiving element at or near its focus.