Overcoming Design Challenges Including Antennae Choice, User Interface and Required Certifications
Challenges in product design and performance appear as IoT medical devices become smaller. These include design functionality, constrained user interfaces, antennae choice, battery considerations, required certifications, and specialty testing.
When space is at a premium, connected medical devices often need a ground up design. Retrofitting previously unconnected devices with IOT capabilities can be a challenge due to constraints of radio system installation and design constraints around the antenna requiring special design considerations.
Device manufacturers need to account for antennas at the beginning of the design process; this will ensure that the device will meet link budget, agency certifications and user expectations when tested. The medical devices must be equipped with the right antennas to deliver robust RF performance, which is crucial for the devices to meet user requirements and pass the required agency certifications.
In battery powered devices, power consumption is a critical factor. Efficient antenna performance is required in order to meet the link budget performance. Efficient, reliable antennas and RF performance are critical to avoid unnecessary drain on the device’s battery and to ensure connectivity.
Connected devices must undergo a stringent certification process with the FCC or CE. Additionally, if cellular connectivity is used, it must also be certified by the mobile network operator. In cases where a chip down vs. a module approach has been chosen for BT, BLE WIFI etc., additional certifications may be required.
Unfortunately, there is no global certification body in place with universal standards. In the United States, the FCC is the certifying body; in Canada, it’s Industry Canada (IC); in the European Union, testing is performed against the European Telecommunications Standards Institute (ETSI) requirements for CE approval. Each country you wish to sell into will have similar, but also very different, certification and testing requirements.
In the US, FCC Part 15 regulates unlicensed radio frequency transmissions, both intentional and unintentional. Product Certification testing must be performed by an accredited laboratory and documentation is then supplied for review by a Telecommunication Certification Body (TCB), or, in some cases, the FCC itself.
Regarding wearable medical devices, excessive exposure to radio frequency (RF) energy can damage human tissue, therefore Specific Absorption Rate (SAR) testing is required to certify the device to RF exposure standards. In the United States, the FCC regulates SAR under 47 CFR Part 2, section 2.1093. In the European Union, RF exposure limits have been established by Council Recommendation 1999/519/EC.
In addition, the device may require security testing for man in the middle attacks, data encryption, and device access through uncontrolled ports or sockets. New standards such as UL2900, are being ratified to standardize the requirements for security performance.