How to Read Antenna Articles

There are lots of antenna articles out there. How do you make sense of them?

Perhaps the most important starting point is to understand that there are 3 major components to any antenna: the electrical design, the mechanical construction, and the feed method.

The electrical design determines the behavior of the antenna – the radiation pattern, gain, etc. For example, a half-wave dipole still acts the same regardless of the construction or the feed method (as long as there is no common mode current on the feedline).

The mechanical construction relates to the actual element and supporting materials, and how they are assembled. This affects the weight and physical properties of the antenna, but not the radiation pattern. A dipole might be made from heavy aluminum tubing to go on a tower, or light wire for backpacking.

The feed method relates to how the RF gets from the transmitter to the antenna (and vice versa). It includes any needed impedance matching. So a half-wave dipole might be fed directly with coax, or use a balun, or be in the form of a folded dipole with two parallel wires, or use a delta match with open wire feedline, or be fed off-center or at one end, but it still acts like a half-wave dipole.

Very often the author of an antenna article is really describing something different about ONE of these components – the other parts of the antenna are pretty standard. However, such components are relatively independent of each other, and can be applied to different antennas.

For example, I might describe how to use a delta match to feed a portable yagi, as it allows me to attach the feedline to the driven element with alligator clips, and the driven element is continuous through the boom for strength. This may be a useful feed method that can be applied to other types of antenna (such as dipoles or quads). Meanwhile, the electrical design of the yagi in the article (the details of the element lengths and spacings) could be fed with some other method to achieve the same pattern, and the mechanical construction can also varied, or copied for other purposes. (Sometimes the dimensions may require some modifications, depending on the type of change you make.)

So when you read through an article, identify the different components, see which ones are new or unusual, and add them to your repertoire. Then, when you go to design or build an antenna, you can choose those that best fit for the desired application, rather than trying to exactly duplicate a specific design from a particular article.

If you read antenna articles this way, as a collection of basic building blocks, then you can use those blocks in different combinations for your own antennas.