A robust custom FPC antenna for potted devices in construction industry.

A robust custom FPC antenna for a ConcreteNDA sensor that yields stable signal and great communication range.

Customer's background:

Working on a mission to bring the construction industry to the digital age with the help of IoT products and services, Converge is a fast-growing, well-known name among construction companies in the UK. The company offers complete solutions from cutting-edge wireless sensors to IoT platform to help construction companies stay on schedule and improve business efficiency, safety and sustainability.

The challenges:

Continuous improvement is what drives a business forward, and this applies to Converge too. When the hardware team found out that the current communication range was not sufficient, as well as the wireless signal of the selected off-the-shelf FPC antenna was not stable, they didn't hesitate to seek advice and support about antenna/RF from Radientum to find a good solution.

The key questions and concerns were:

• How to improve the current antenna that the team won't need to change the size and shape of the sensor?
• Is there a possibility to find an antenna solution that'll achieve sufficient communication range without making significant changes to the device's mechanics and materials?
• Would it take too long time to find and implement necessary changes so that they still meet the project's schedule and product launch?

A few challenges and goals were highlighted and discussed:

• Concrete sensor's size is very small (50 x 40 x 25 mm), a battery-powered device that typically creates losses to RF performance.
• The wireless signal should be stable when installed inside concretes where the condition changes from wet concrete to dry concrete.
• The sensor is a potted device and will be installed on a metal bar inside concretes. Being close to metallic surroundings also brings losses to antenna performance. Thus, the antenna should be designed to work for these specific use case environments.
• Due to the construction environment, the antenna solution should be robust and yield stable signals.

The solutions:

Radientum proposed to first check the current antenna performance with measurements to study the current situation. Within a couple of days, measurement was done and results were analyzed. The conclusion was that, even with antenna tuning and optimization, the current antenna performance will not meet the project's specifications. Thus, a custom antenna solution was proposed.

With simulation-driven approach, after just a week, a new antenna construction was delivered for review. Radientum's engineers worked closely with mechanical and HW engineers of the customer to discuss and implement design changes to enable optimal antenna performance. The antenna design file was released not long after that for prototyping manufacturing.

The antenna performance was checked in both free space and inside a concrete sample to ensure its performance in the real use case.

The solution was a robust FCB antenna that is custom-designed to work perfectly in the customer's device-specific environments. Prototypes measurement results showed stable signals with a communication range of 10 meters as expected.

Results for customer's business:

• Converge launched the platform as planned
• Antenna performance met the project requirements

Founded in 2014, Converge digitises the entire construction process by building AI and cloud-based technologies that are powered by a suite of proprietary wireless sensors.