What are the three types of antennas?

The correct answer identifies the three types of antennas as omnidirectional, bidirectional, and unidirectional, which are commonly discussed in the context of antenna design and functionality.

Omnidirectional antennas are designed to radiate and receive signals equally in all horizontal directions, making them ideal for applications where communication is needed from multiple angles, such as in wireless access points.

Bidirectional antennas are characterized by their ability to transmit and receive signals in two specific directions. This is particularly useful in applications where communication between two points is needed, such as two-way radio systems.

Unidirectional antennas focus the signal in a single direction, allowing for a stronger connection over greater distances in that specific direction. This can be advantageous in scenarios such as point-to-point communications or in applications where interference from other angles needs to be minimized.

The other options include terms that either do not accurately represent standard classifications of antennas or combine types in ways that do not reflect practical uses. For instance, isotropic refers to a theoretical antenna that radiates equally in all directions, but it is not typically categorized with the practical designs of antennas. Similarly, parabolic antennas, while effective for focusing signals, are a type of directional antenna rather than a stand-alone category.