How Multi-Band Antennas Solve a Key IoT Design Challenge

Technology has a habit of getting smaller, and IoT devices are no different. Computers shrink to fit in our pockets; chunky GPS receivers give way to dime-sized tracking tags. Oversized smartphones notwithstanding, miniaturization is the norm in today’s IoT landscape.

But miniaturization runs head-first into the other big IoT design trend: network proliferation. To compete in today’s consumer IoT market, you might need more than Bluetooth, Wi-Fi, or cellular connectivity. For many devices, consumers will expect all three (and then some).  

Each of these technologies operates within a different radio frequency (RF) band. Traditionally, you could only pick up each band with a dedicated antenna.

To support multiple connectivity options, then, you’d have to pack your device with antennas. That might not work with your device form factor. If you’re building smart watches, asset trackers, or condition-monitoring sensors for delicate machinery, it probably won’t.

Even worse, antennas can interfere and couple with each other. Coupling and interference from one antenna can impact another, causing it to fail unexpectedly. In short, using multiple antennas successfully is harder than it looks.  

Even if antenna interference weren’t a problem, however, this is the challenge today’s IoT design teams are facing. It’s hard to create devices that are both:

1. Smaller than ever, and;
2. Compatible with networks across the RF spectrum.

Multi-band antennas provide a strong solution. Here’s why a multi-band antenna could be the best choice for design teams facing size constraints and the need for flexible connectivity in the same device. 

The Role of Multi-Band Antennas in IoT Device Design

Multi-band antennas are just what they sound like. They can receive multiple frequency bands (which is why they’re also sometimes called “wide-band antennas”). This capability allows your device to connect using several IoT connectivity technologies, from Wi-Fi to LoRa to NB-IoT or LTE—or even the latest 5G IoT protocols. 
  
You can get these multi-band capabilities in small packages, like patch, flexible PCB, LDA, or even chip antennas. However, chip antennas are generally low-efficiency and sometimes need a fair share of ground keep-out area to operate. If you need seamless connectivity, these are the small-form-factor antennas you want. Multi-band antennas are probably best suited for mobile consumer devices, like wearables and smart transportation.

Of course, frequency range is just one of many factors to consider when choosing an antenna for your device—and that’s a decision you don’t want to make lightly. 

How to Choose an Antenna for Your Next IoT Device

Antennas are the unsung heroes of IoT product design. Pick the wrong one, and your range and connectivity will suffer. Fail to deliver on range promises, and your brand can be permanently damaged. Without expert guidance, you might use a high-gain directional antenna when you need low-gain omnidirectional coverage.

Worst of all, it’s hard to spot these issues until you’re in the testing phase—by which time you’re dangerously close to a delayed release (especially if you fail your LTE certification).  

So what’s the solution? Here are a few tips for choosing the right antenna for your IoT product:

• Choose your antenna as early in the design process as possible—ideally before you settle on a layout.
• Consider investing in custom or semi-custom antennas. Although they may look more expensive than off-the-shelf models, avoiding problems later in the design process often saves upfront costs.
• If you do use an off-the-shelf antenna, don’t trust the datasheet without verification. How you integrate an antenna affects performance almost as much as the antenna’s specifications.
• Counter this uncertainty with extensive computer simulations and field testing.
• Don’t settle for industry standards on range. Aim for one to three dBi over the standard gain target to guarantee great performance in the field.

If all that sounds complicated, that’s because it is. The good news is that you don’t have to handle the make-or-break decision on your antennas alone. When in doubt, look for a design partner specializing in antenna customization and RF integration in small form factor IoT devices.  

Such a partner can help you decide whether a multi-band antenna is the right choice for your product. They can even design a custom antenna for your unique use case. Given the central role antennas play in IoT performance, it pays to work with the experts.