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RADIUS
Product
Description
PDR221
iom_pdr221_04_r02.doc
Rev 02
Page 37 (60)
11.1.2 Antenna Types
There are basically two categories of antennas, omni-directional and directional. An omni-
directional antenna radiates in all directions. A directional antenna radiates in one direction only. An
omni-directional antenna should not be confused with an isotropic radiator. While an isotropic
radiator will radiate in all 3 dimensional directions, an omni-directional antenna may not radiate
vertically (up or down).
11.1.2.1 Directional Antenna
Below is an example of a 14 dBi gain directional antenna. The field strength diagrams show the
direction of maximum radiation of the antenna. The E plane represents the electric field and the H
plane represents the magnetic field. The E plane and the H plane are orthogonal to each other.