Active Antennas: The Basics of These Systems


The pace of technological progress is impressive. It’s never been this easy to send large amounts of data fast. The next stop includes 5G networks, and companies need to find ways to meet customer needs. 5G offers impressive capabilities, and active antennas might be the way to secure them. This article focuses on active antenna systems and how they work. We’ll also discuss when sticking to passive components might be a better choice!

Table of Contents

What You Should Know About Active Antennas

TV aerial antennas

Caption: TV aerial antennas

The definition of an active antenna is complex. These advanced antenna systems have many stationary elements, and the coherent feeding and using time-delay control or variable phases serve for beam scanning at certain angles. So, there are no moving components in active circuitry. The beams have electronic steering, which occurs in the ICs in the antenna’s radiating elements.

The design of active antenna arrays has many elements. So, if a few break down, the antenna should keep working. You’ll often find beamforming architectures featuring many independent steering beams, which are reliable because there are no gimbaled parts. Integrated active antennas can block jammers and interferers, which results in precise patterns. 

How does this work for 5G networks? The frequency of operation is from 24 GHz to 39 GHz. Therefore, the lengths of waves will be short. You can place elements in a directive aperture to mitigate path loss. More beams can have an identical frequency spectrum, which boosts potential system capacity.

Beamforming Architectures

Caption: Telecommunication tower emitting signals – illustration

You’ll need some arithmetic knowledge to analyze forming of these beams. For example, you might find linear spacing of antenna elements on the same axis. The gap is equal to half of the free-space wavelength. That ensures coherent beamforming in the preferred direction.

You’ll find various setups in active antennas, ranging from analog and hybrid to digital beams. Here is how to choose between the available options!

Why Use Analog Beamforming?

An expert working on installing an antenna setup

Caption: An expert working on installing an antenna setup

Analog beams have shifters in each array element. You need ADC and a frequency downconverter to comply with the setup.

The main advantage of analog setups with a balanced amplifier is that they are easy to install. You won’t find hardware that’s easier to implement. Furthermore, it fits lattice at high frequencies, which adds versatility. There’s a full array gain in the beam, which is helpful. Another advantage is that the system uses the lowest DC power.

As for the cons, there’s only a single beam. And although these are high-quality products, you can’t change the number that comes with the hardware.

Why Use Digital Beamforming?

Caption: An antenna system

Digital beams don’t have analog shifters. Instead, they use digital weights. Each element in the active array antennas needs a full receiver chain, and it goes from the antenna element to digits. These setups can have various nulls and beams, which offers excellent flexibility. Therefore, these can have many beams, and it only depends on product details.

Another significant benefit is that you can adjust the beam number in these intelligent antennas, which is possible without changing the hardware, which is convenient. The full away gain is available in each beam.

The downside is a complex setup that has routing complexity. You’ll notice it in LO and I/Q signals, and it can lead to IQ imbalance. The hardware is demanding since each element should have a full RF chain. Additionally, it won’t fit the lattice at high frequencies.

Hybrid Beamforming

Caption: Coaxial cables that transmit satellite signals – close-up

This antenna technology features a mixture of digital and analog beamforming. The system forms analog beams from a part of the full array. The biggest con of this setup is that digital beams can only be a part of analog ones.

Hybrid setups have many advantages. You can secure maximum network performance with a high number of beams. If necessary, you can adjust the beams without modifying the hardware. Additionally, these systems have great flexibility with the number of nulls and beams.

Digital beams can’t fit hardware at high frequencies while being within the lattice. You resolve that problem with a hybrid setup. Also, there is no Los in the array, and you avoid complex signal routing.

When Should You Use Passive Antennas Instead of Active Ones

A pole with a digital antenna for broadcasting

Caption: A pole with a digital antenna for broadcasting

The vital thing is to distinguish between two different antenna designs. An active antenna unit comes with integrated amplifiers, while passive antennas don’t have them. Apart from that, there’s no difference in elements.

So, active antennas can both send and receive signals. However, most users see them as receiving antennas, and the unit picks up the RF signal while the amplifiers boost it. Thanks to that setup, you can apply a coaxial cable at larger distances.

Your transmitting device, such as a wireless transmitter, has a certain output, and the integrated antenna components ensure the RF power goes beyond that potential. On the other hand, the RF signal going through a cable loses strength. Therefore, it makes sense to use active elements to mitigate this loss. The idea is that the receiver gets almost equal signal strength from the sending unit.

It’s worth noting that active antenna measurements don’t affect the electrical features. So, an active unit won’t help it to pick up more energy. If you don’t need to amplify the signal, go with passive components.

There’s also no need to go for passive units if cable loss is negligible. For example, a 50-feet UHF cable won’t lose many signals. You should use passive antennas because active ones can lead to bad audio, and it also compromises the general health of your setup. Another reason to avoid active measurements is that directional antennas can compensate for small losses.

It’s possible to get a passive antenna and add an integrated amplifier later. The good news is that fiber optics minimizes signal loss even at large distances. Today, the price is lower than before, which makes it a fine choice for most uses.


The technology has gone a long way from conventional antennas to complex antennas systems we have these days. Active units come with a preamplifier that boosts the RF power. If you need it in your setup, you can pick these antennas. Don’t hesitate to contact Cloom for reliable cabling regarding your applications!