The connected medical device market is booming, driven by the need to increase efficiency and accountability, drive down treatment costs, and improve patient care. Internet of Things (IoT)-based medical devices can get patients out of the hospital more quickly, or keep them out altogether, and save organizations money. Many medical devices today are being marketed more as “wellness solutions” rather than medical devices, encouraging increased usage by changing the terminology from a product designed to monitor health concerns to one that encourages wellness.
Healthcare devices such as insulin pumps, defibrillators, CPAP machines, cardiac monitoring devices and oxygen tanks are now quite entrenched in remote monitoring, providing patients (and their caregivers) valuable real-time information, without being tethered to a hospital or healthcare facility. In 2016, the remote patient monitoring market grew 44 percent, with 7.1 million patients enrolled in some form of digital health program featuring connected medical devices as a core part of their care plan, according to market research firm Berg Insight. Berg estimates the number of remotely monitored patients will reach 50.2 million in the next four years, with 25.2 million comprised of those with connected home medical monitoring devices and the rest coming from personal health devices.
IoT-based medical devices, of course, need to connect to the healthcare cloud, and that means they need both a reliable antenna and a reliable connectivity medium. Network connectivity with ease, consistency and quality of connection can make or break an IoT solution.
Cellular is the connectivity solution of choice by healthcare organizations as they allow patients to be truly mobile—and because cellular’s turn-on-and-go capabilities are more reliable, familiar, secure and easier for a patient to set up. Secure Wi-Fi, on the other hand, has login protocols and physical network restrictions, which might discourage or disallow use by some patients and caregivers. A login screen, for example, is required to set up the device on each individual Wi-Fi network, whereas cellular devices can be activated one time by the solution provider and deliver global connectivity, if desired. Cellular networks were also built for more robust usage by multiple parties, and won’t slow down in the same way Wi-Fi networks do when there are too many users on the network. The ubiquity of cellular networks allows devices to work just about anywhere.
The antenna is the physical link to network connectivity for medical devices, converting electrical signals into radio waves for transmitting and the opposite for receiving. An efficient, reliable antenna is critical, especially when devices are used in areas with weak signals, for example, in more rural areas. In addition, if the antenna is not efficient, the device is working harder to achieve or maintain that connectivity, putting excessive strain on the device’s battery.
As medical devices become more sophisticated, their form factor is shrinking, which will encourage even further market growth. However, with sophistication and size constraints comes complexity and challenges. These include—among others—design, performance and certification challenges. Organizations may struggle in the design and testing phases of medical device development because they lack awareness of the antenna and its necessary certifications.
The design process for a device that is remotely monitored is different from those designed for in-hospital use, and—frankly—different from common IoT devices, such as telematics or security devices. In addition, while the form factor for devices like a cellular phone has standardized on a thin rectangular shape, and other more industrial IoT devices take a box shape, connected medical devices need to have a topology and layout specific to their use case. Medical devices themselves are often uniquely shaped and contain high-powered electronics that can interfere with the device’s radio performance. In addition to making devices more compact, if they are body-worn they also need to be as comfortable as possible and discreet—or they won’t be worn by the patient they are intended to help.
One common issue in this vertical IoT market is trying to retrofit previously unconnected medical devices by adding cellular capabilities, while the enclosure, battery size, main PCB shape inside, etc., remains the same. Trying to retrofit an antenna into any device is difficult, as space and layout for antennas were not considered, hence there is usually nowhere for an antenna to find a place for it to radiate efficiently. It means a custom design and more bespoke integration is required, as well as a healthy dose of creativity to ensure the device is not only reliable, but exceeds user expectations from a wearability perspective. It’s important that medical device companies incorporate and plan for antennas during the beginning of the design process to ensure that the device will meet certifications and user expectations when tested.
Another common misperception is that cellular devices are similar and modules are pre-certified so a one-size-fits-all approach is taken. However, a defibrillator is very different from an insulin pump, not only in the function which it performs, but also in the high-powered electronics inside. Its more often the case that each antenna needs to be custom fit for the device it’s serving.
Performance, and the Certification Process
A critical factor for companies looking to bring connected devices to market that is often underestimated is the wireless device certification processes. In North America, this is separate to the FDA testing and is required for all wireless devices. Regardless of whether a device is completely new or is an existing device that the manufacturer is trying to connect, all must pass through a stringent certification process with not only the FCC and CE, but if cellular is used, by the mobile network operator as well. Connected medical devices need to meet certain certifications and a certain level of network performance. As well as being tested on meeting certain network standards and scenarios, medical devices are tested on how well they send and receive data, as well as determining on how weak a signal they can receive while still being connected. This testing for device transmit and receive sensitivity is known as Over the Air (OTA) testing.
As well as the size and shape of the device, devices worn on, or close to, the body drastically affect the antenna and RF system, so the manufacturer will need to consider this and the potential of extra testing and certification, such as SAR (Specific Absorption Rate), if there are voice or heavy data functions for the application. This is not the norm for IoT devices, as they are never usually worn on the body, so the designer needs to ensure that the RF team has the experience and test equipment to be able to overcome these challenges.
The device, of course, has a specific function, and this usually means there are noisy electronics and activity in proximity to the RF and wireless system, which will always cause interference and impact performance with any wireless device. Custom antenna and filter designs can help compensate for these effects, but will never fully eliminate them. Medical devices may also be battery powered, so power consumption is also often a critical factor; best-practice RF design to minimize noise and interference and very efficient antenna performances are needed so the device is not losing power when receiving or transmitting.
Ensuring that medical devices are equipped with the right antennas to deliver robust cellular connectivity is vital for the devices to pass the required certifications first time and on time so as not to delay product launch.
Collaboration A Key Requirement
Medical device manufacturers often underestimate the complexity of integrating wireless into an often already-complicated product. The requirements and pitfalls associated with medical device design and development are such that medical device companies can’t go down the path alone. Ongoing communication with all the partners required for success in the connectivity landscape is essential in the device build process, and should be consulted before a design is started. Trusted partners include mobile network operators, antenna and RF vendors, module or chipset vendors, and test labs. They can help device manufacturers understand:
- The key requirements of successfully deploying devices in any location globally
- Alternative or complementary connectivity options, such as LPWAN or satellite
- The common pitfalls of the device certification process, and how to avoid them
- Best practices wireless device design
Going down the wrong path in terms of connectivity can be averted through consultation with an antenna vendor at the very beginning of the process to discuss not only antenna selection—size, shape, mounting type, location, price, etc.—but also carrier certification, testing plan, installation requirements and more. Retrofitting antenna solutions can be a painful process that is avoided if the antenna vendor is involved early.
Connected medical and wellness devices are becoming much more mainstream, and that’s untethering people from required hospital and doctor’s visits. However, the process to bring them to market is cumbersome and can be filled with false starts. Understanding the key design, performance and certification issues early in the process by involving an antenna supplier in the process can help eliminate many of the challenges and direct medical device manufacturers down the correct path.
About the author
Dermot O’Shea, co-founder and joint CEO of Taoglas, is a seasoned IoT entrepreneur, with more than 15 years’ experience in the global electronics industry spread over roles in Europe, Asia and North America. He is recognized as an expert in the antenna and wireless business. O’Shea currently serves as Joint CEO of Taoglas Group and president of Taoglas USA – the leading machine-to-machine/IoT antenna solutions provider. O’Shea co-founded Taoglas with Ronan Quinlan in 2003, and together they have led the company to exponential profitable growth. O’Shea has also helped Taoglas earn recognition globally as the market leader for M2M and IoT antennas.