 Hey everybody, it's Tossos with RF Elements and today we'll be talking about radiation diagrams of antennas. The radiation diagram of an antenna describes how strongly an antenna radiates in any direction. It's also called a radiation pattern and it's one of the most essential parameters of any antenna. So why is that important? It's because the shape of the radiation pattern determines the application for the antenna. Antennas transmit energy in three-dimensional space. To display this would be extremely difficult without very powerful computers. This is why scientists introduce a simplified method to describe radiation diagrams in a two-dimensional plot. This two-dimensional plot is still used today and let me explain how they work. So this is the visualization of the radiation of an antenna. In this example, we picked a parabolic dish antenna. The intensity of the color corresponds to the energy level. With directional antennas we call the access of maximum gain, the Bohr site. For directional antennas, the Bohr site is the access of symmetry for the antenna. Now let's label angular direction with zero degrees at the Bohr site. And then measure antenna gain at every angle. And we mark the intensity of energy at every point. If we cut the space diagram on the horizontal plane, we call this the azimuth cut. If we cut the diagram on the vertical plane, we call this the elevation cut. Polar plots show how gain changes with angle. The number around the outer circle represents the angular direction of this radiation. The inner circle represents the axis that represents antenna gain. The gain value is read by looking where the points on the plot intersect with the inner circle. Polar plots are the most common way of visualizing radiation diagrams. But it may be difficult to read due to the circular gain axis. Let's straight the circular gain axis and we get an xy plot. Let's talk about that. An xy plot has two axis, x for angle and y for gain. Gain at a particular angle is read by intersecting the points on the plot with the axes. Two-dimensional graphs are okay to describe simple, clean and symmetrical radiation diagrams just like a symmetrical horn antenna. But remember that the limitation of two-dimensional interpretations are huge when describing complex radiation diagrams or non-symmetrical radiation diagrams where two cuts are simply not enough to describe them. Do you want to know why three-dimensional diagrams are better than two-dimensional diagrams? Check out some of our upcoming videos and we'll show you why.