<P> Antennas can be designed to transmit and receive radio waves in all horizontal directions equally ( omnidirectional antennas ) , or preferentially in a particular direction ( directional or high gain antennas ) . An antenna may include parasitic elements , parabolic reflectors or horns , which serve to direct the radio waves into a beam or other desired radiation pattern . </P>
antennas that transmit an equal amount of energy in the horizontal direction are called
omnidirectional antennas