Antennas

While all radio technogies rely on antennas to operate, the frequent use of short range radio technologies often hide the need for an excellent antenna to function perfectly. As a very long range technology, Sigfox necessitates a specific focus on antenna design which must be taken very seriously from the very beginning of the design process. 

Here, we will explain how antennas should be designed and what options are available in order to get the best out of your connected device. 

Introduction

Why is the antenna the most critical component of my design ?

Looking at the different elements that impact the quality of Sigfox connectivity, the device antenna is actually the only parameter that can drastically reduce the link budget (and therefore device connectivity) and that you can have an impact on as a device maker.

Sigfox base stations are installed in such a way that in normal conditions, the Sigfox Network ensures excellent coverage. Coverage is continuously being optimized and improved. Between the device and the different base station, some propagation effects may impact the budget link and in most cases, there is nothing much that can be done about this: for example. If your device is installed on a shop door and a big truck parks right in front of the door, this will automatically change the propagation conditions. 

This kind of situation is taken into consideration in Sigfox's network deployment and supported in most cases. From a device perspective, most RF transceivers provide the recommended power level (14dBm or 22dBm). Therefore, the only parameter which can decrease device connectivity and on which you can have an impact is the device antenna quality.

This is why it is important that the radiated performance of your device be optimal and thus that the Sigfox antenna for your device be well designed and implemented.

How?

An antenna is not a standalone component but uses and interact with all other components/physical parts of your device. Therefore, to succeed in your device antenna integration, you should consider it from the beginning of your device development. The earlier you start considering the antenna in your device development the more chance you have to end up with a high-quality product.

Because an antenna is impacted by its close surrounding, it is important to select the right antenna solution according to not only your device architecture but also your device use case and the way the device will be installed and used.

Once your device is designed and certified, it is also important to make sure that the way the device is installed does not decrease its radiated performance. 

In short, optimizing the antenna design for your device and its use case as well as making sure that your device installation does not reduce its radiated performance, will have a huge impact on the Sigfox connectivity quality.

Off the shelf antennas

Using a custom-made antenna should seriously be considered to obtain maximum radio performance from your device, However, a lot of off the shelf antennas are readily available on the market and can be integrated into your device.

Antennas can be designed in a lot of different ways, to match with the variety of use cases on the market. They can be very different in term of sizes, form and integration, but also in terms of performance. To ensure the maximum radiated efficiency of your device, be sure to choose one which fits your environment, use case, and coverage needs. 

For an overview of all companies designing antennas, please consult Sigfox Partners Network and at Mouser (example for 868 MHz) or Digikey for an idea of the form factors available in the market today

Please note that all these off the shelf antennas are designed to be used in particular use cases and may not be compatible with yours. They are also often optimized for a specific device form factor. Also please be aware that antennas are optimized for specific frequencies, so be sure to select one compatible with your radio zone.

Most antenna manufacturer also provide support to select the best antenna for your specific device form factor and use case. So do not hesitate to contact them.

Whitepaper

In order to help our ecosystem to develop antennas, a white paper in which details several aspects of antenna design and integration is available. You will find ideas, good practices and advice on what can and what cannot be done while designing your antenna. 

Antenna Design for Sigfox Ready devices

You need to log in or sign up to download this ressource. 

Open source antenna

Please find below an example of an antenna designed by our very own experts for the Sens'it, our multi-sensors devices developed in close collaboration with our partner Axible.

We designed this device as an example of what can be done with our technology, and we decided to open source the design of this antenna to inspire other device makers.

This antenna can operate in all of the major Sigfox radio zones (from 868 to 923 MHz) and can be easily reused in other devices which have a form factor similar to the Sens’it. The integration guide below will help you to integrate and adapt the Sens’it antenna to your device.

Open source Sens'it antenna design

You need to log in or sign up to download this ressource. 

Antenna Designers