Antenna radiation patterns are the mathematical representation of the radiation energy distribution with respect to the directional coordinates.
Antenna radiation pattern plots using the spherical coordinate system form 3D antenna radiation patterns.
From the 3D spherical plots of antenna patterns, it is possible to obtain 2D polar plots.
Antenna radiation patterns are of great importance in any application that involves the transmission or reception of electromagnetic signals. These patterns pictorially represent the radiations associated with an antenna and describe the radiation properties of the antenna. From antenna radiation patterns, engineers can determine whether an antenna’s performance is suitable for a particular application.
There are many types of antenna patterns, including 2D and 3D antenna patterns. Depending on the antenna type, the dimensional preference of the antenna pattern plot changes. In this article, we will take a closer look at 3D antenna patterns and why they might be helpful.
What Are Antenna Patterns?
An antenna radiation pattern is the mathematical representation of the radiation energy distribution with respect to the directional coordinates. An antenna radiation pattern depicts various radiation properties such as:
- Radiation intensity
- Power flux density
- Field strength
- Radiation efficiency
- Effective aperture
Generally, an antenna radiation pattern plots the radiations and spatial distribution of electric and magnetic fields as a function of the space coordinates, which are called power patterns and field patterns, respectively. Antenna radiation pattern plots using the spherical coordinate system form 3D antenna radiation patterns. In such spherical antenna pattern plots, the antenna is the point of source or origin and the three-dimensional view of the radiation spread can be observed.
The Differences Between 2D and 3D Antenna Patterns
From the 3D spherical plots of antenna patterns, it is possible to obtain 2D polar plots. Dividing 3D spherical antenna pattern plots in the horizontal and vertical axes is how engineers obtain 2D plots. The 2D plot from the horizontal division is called the horizontal pattern, whereas the 2D plot from the vertical division is called the vertical pattern.
Antenna patterns provide a lot of useful information when selecting antennas for specific applications. Choosing between 3D spherical plots or conventional 2D polar plots is heavily dependent on the antenna type and the expected performance.
2D polar plots are recommended for testing highly symmetrical antennas with excellent directivity. For testing new designs of antennas or unknown antenna types, 3D antenna patterns are most suitable. A spherical antenna plot or 3D antenna pattern catches all flaws or disturbances present in the pattern. It covers any pattern imperfections due to enclosures, printed circuit board edges, or feedline interactions.
The table below compares 3D and 2D antenna plots.
A comparison between 3D spherical antenna pattern plots and 2D polar plots
3D Antenna Patterns of Omni-Directional Antennas
Omni-directional antennas are antennas that radiate electromagnetic waves uniformly in all directions. An omni-directional radiation pattern is similar to an isotropic radiation pattern. The 3D antenna pattern of an omni-directional antenna resembles that of a donut. When converted into a 2D plot, it is a figure-of-eight pattern. The 3D antenna pattern shape of an ideal omni-directional antenna can be taken as the reference for antenna patterns.
The 3D antenna patterns used for the analysis of antenna characteristics are mostly computer-generated. The plots obtained from these simulations are surprisingly close to the real radiation patterns that are measured. Cadence software offers EM analysis tools that help antenna designers derive antenna radiation patterns.