Aerospace operations are a core part of most modern military force. Every nation has a vested interest in deploying the tools that it needs to defend against them, and those tools are often highly specialized. Antennas are a common element in those defense systems. They may only be a single component in a larger device, but they are often the core component that allows vital parts to function. They can play a lot of roles, and anyone who wants to understand defensive systems must understand them.
The weather has a massive impact on all aerial operations. Most vehicles struggle to fly in bad weather, and even those that can make it into the sky suffer from reduced visibility and performance. That means that tracking the weather is vital, and most of those systems depend on some sort of antenna array to get their data.
Military leaders try to make their decisions based on the best data available, which is why they dedicate so many resources to gathering that information. They need to be able to get those findings as quickly as possible while the information remains relevant. Standard wireless communication systems rely on antennas to send and receive information, and those systems are the vital supply lines for information. Every person in the defense system relies on them, either to get the information they need to make vital choices or to pass those choices on to the people who can carry them out.
A defense system can only stop a threat if it can detect that threat in the first place. That is often easier said than done, because modern military forces are extremely good at preventing detection. The result is a constant race between concealment and detection technology. Many of the successful systems work by using antennas to bounce waves off of items in the sky. They can then analyze the waves that come back to see if anything important is in the air. There is no such thing as a perfect detection system, but that is the core mechanism behind many of the most effective options that defense experts have at their disposal when planning a system.
Machines are a vital part of the modern battlefield, but somebody still needs to control them. Most of the controllers do so via a wireless connection, which reduces their exposure to danger and frees vehicles from the constraints that come with supporting a pilot. Antennas are vital tools for allowing commands to reach those machines, and most of them could not function if they had to depend on a pilot that was controlling them in the field.