Omnidirectional Antenna structures produce an uniform radiation round their vertical axis (azimuth).
Axial Collinear Antennas
Directional Antenna stuctures have their radiation focused, generally within a single area of interest.
Crossed Yagi Antennas
Stacked Yagi Antennas
Hemispherical Antenna structures have their radiation distributed primarily over a hemisphere (half of space).
Volute/Quadrifilar Helical Antennas
Crossed Loops/Egg Beater Antennas