Is an Antenna Passive or Active?
Today, as we continue exploring topics around LTE and network communication, let’s understand the nature of antennas. You’ve probably come across both the terms “passive antenna” and “active antenna,” and it’s completely normal to wonder what makes one different from the other, or which one is typically used in telecom networks.
Let me walk you through it clearly so you can easily differentiate between the two and know when each type is used. Since we already discussed related things like eNodeBs and signal performance (like RSRP and SINR), this will connect directly to that understanding.
Passive Antenna
A passive antenna doesn’t have any built-in amplifier or electronics. It just receives or radiates electromagnetic waves. When you look at most traditional base station antennas or older home antennas, they fall under this category. Here’s what defines it better:
- It doesn’t require power to operate.
- It doesn’t amplify the signal—it only transmits or receives it as-is.
- It’s typically used in environments where signal levels are strong enough on their own.
- It’s reliable and has fewer points of failure because there are no electronic parts inside.
Active Antenna
Now, an active antenna is a different story. This type of antenna includes electronic components, such as amplifiers, and it needs a power source to operate. You’ll find these more in advanced systems like modern LTE and 5G base stations, especially where higher performance or smarter beam control is needed.
- It includes active electronic components (like LNA – Low Noise Amplifier).
- Requires power to function.
- It can amplify signals either before they are transmitted or after they are received.
- Often used where signals are weak or need to be precisely managed—such as in dense urban areas or with Massive MIMO setups.
Comparison Table
| Feature | Passive Antenna | Active Antenna |
|---|---|---|
| Power Required | No | Yes |
| Contains Electronics | No | Yes |
| Signal Amplification | No | Yes |
| Application | Simple base stations, rural setups | LTE-Advanced, 5G, urban networks |
Which is used in LTE?
In LTE networks, both types of antennas are used, depending on the specific need. For example, traditional macro sites may use passive antennas. But in advanced LTE deployments like LTE-Advanced or when you see the use of beamforming or Massive MIMO (as we discussed in earlier topics), active antennas come into play. They allow the system to direct signal beams dynamically, improving performance and efficiency.
You can think of passive antennas as straightforward transmitters and receivers, while active antennas are more intelligent—they not only handle signals but also process and enhance them before sending or after receiving. If you remember our earlier explanation of beamforming, that feature heavily relies on active antenna systems.
So, to answer you simply—an antenna can be either passive or active. And whether to use one or the other depends on the network design and performance goals. If you’re diving deeper into LTE planning or just want to understand signal behavior better, it’s helpful to keep both types in mind.