Miniaturization in Medical Devices: The Role of RF Connectors 

The demand for smaller, wearable, and implantable devices is driving the use of compact RF connector solutions.

The COVID-19 pandemic greatly accelerated the growth of telehealth and remote patient monitoring, with a new generation of portable and connected medical devices offering convenience, immediacy, and precision to patients and providers. This rapid transformation of the healthcare landscape has been supported by the rise of compact, high performance radio frequency (RF) connectors, especially the miniaturized coaxial types used to connect antennas in wearables, portable monitors, and home-use medical devices. RF connectors enable wireless communication functions via Bluetooth, Wi-Fi, or LTE, making it possible for home-use medical devices to collect vital data at the patient point through a wearable monitor, small portable unit, or an implanted device and deliver those findings to a physician, an app, or a medication delivery device, such as an insulin pump.

The shift towards telemedicine was happening before the pandemic, but that really accelerated things, because we needed a lot more medical equipment, and because there was an absolutely massive equipment upgrade cycle. People went home and started upping their bandwidth to support the devices that they brought into their home. This also helped people get used to having more connectivity and using technology for more things, including health management,” said Travis Amrine, marketing manager at I-PEX. “Now people can take their own blood pressure at home with a connected device, and that data can be uploaded in real time to the doctor, instead of telling the doctor days later at an appointment. And that’s a simple example; devices can now take a wide range of vitals at home or be used continuously for monitoring. This whole category of products owes its existence to miniature RF connectors.”

I-PEX MHF 1 Connectors support up to 9 GHz, mated height of 2.5 mm max. and 3.0 mm max.

This connector type ranges in size from miniature, subminiature, microminiature, and finally ultraminiature RF connectors that operate in the high frequency range. There are a wide range of options suitable for small medical devices in this category, including fully compatible products such as I-PEX’s MHF line and Hirose’s U.FL, and similar connectors from TE Connectivity, COAX Connectors, Molex, and Amphenol. These connectors initially were developed for consumer electronics, said Amrine, but most RF coaxial connectors are dual use and are now used in many different end-use applications. “A lot of our MHFs are in access points and routers, and almost every single connector that I-PEX produces had its genesis in consumer electronics. But very quickly, they were adopted by medical designers because of the small size and light weight. That gives designers a lot of flexibility that has led to incredible innovation in devices.”

As the Internet of Medical Things continues to grow, the integration of RF connectors supports high-frequency data transmission across device types, while maintaining low insertion loss, which is essential for devices that require stable wireless communication. The smallest of these connectors are used in applications where board space and weight are at a premium, such as wearable biosensors, implantable telemetry systems, and diagnostic imaging modules. Their small footprint, typically under 3 mm in mating height, makes them ideal for embedding within densely packed PCB assemblies without compromising RF performance. The ability to operate effectively at frequencies above 6 GHz supports high-bandwidth data communication protocols essential for modern medical telemetry and wireless diagnostics.

When designing these RF connectors into medical devices, engineers must carefully consider both electrical and mechanical parameters. Electrically, maintaining impedance control (usually 50 ohms) is critical to avoid signal loss or reflection, especially in high-frequency applications. PCB layout must include controlled-impedance traces and proper grounding to preserve signal integrity. Mechanically, connector durability and mating cycles are important, particularly in devices that require regular maintenance or recalibration. Many micro-RF connectors are rated for a limited number of mating cycles (typically 30–50), so designers often incorporate them for semi-permanent connections or provide accessible test points for diagnostics.

To meet compliance, connector materials must support biocompatibility, sterilization resistance, and long-term reliability. “Most consumer devices aren’t going to be exposed to an autoclave or radiation, but for the medical device industry, these are still considerations. Some equipment will have to go through like a sterilization process,” said Amrine. So the connectors specified for these devices must withstand sterilization processes if placed within reusable enclosures. Additionally, EMI shielding is a critical consideration, as medical devices operate in electromagnetically noisy environments. Proper shielding design, combined with the use of micro-coaxial cables and connector housings with metal shells, protects operation without interfering with adjacent equipment.

Future developments 

In its 2025 World RF Coax Connector Market report Bishop and Associates finds that sales of RF connectors and cables in the miniature, subminiature, microminiature, and ultraminiature sizes have grown dramatically since the pandemic, and the production for these now-critical connector types will continue an upwards trajectory. Since the lessons of 2020, manufacturing has been moving from China to North American and European manufacturing centers to ensure a stable global supply chain for medical, consumer, as well as small military applications such as soldier wearables and drones.

Hirose U.FL Series Light Weight Micro SMT Coaxial Connector, 1.9mm to 2.4mm mated height

R&D and prototyping currently underway for new RF connector development focuses on shielding, materials, antenna design, and size. “Wearables of any kind clearly push the limits of integrating a lot of electronics into a very small area. This pushes connectors and cables to deliver narrower signal paths and drives the need for finer pitches as well as the need for the outer footprint to be shrunk at the same time,” said Mark Waring, Hirose strategic account management.

“Hirose was an early pioneer in designing and introducing the first mass-produced shielded micro connectors specifically for RF signals with our introduction way back in 1990 of the now de facto industry standard form factor the Hirose U.FL series. The U.FL includes both shielded micro coax cables together with a tightly coupled connector plug and PCB mounted receptacle combination to achieve RF signal performance from four to eight gigahertz. This family continues to evolve today with smaller form factors and higher frequency support from 8 to 12 gigahertz, and more recently we’ve gone back and redesigned a new intermatable U.FL plug cable assembly with much more aggressive shielding, bringing the signaling performance capability all the way up to 15 gigahertz.”

With mated heights of less than a millimeter already possible, small medial product design is well underway, but there’s room to shrink. Amrine says the smallest connectors can be shaken out of a saltshaker. Future medical devices will undoubtedly not only be smaller, but also smarter, safer, and more efficient.

Like this article? Check out our other RF and Coax articles, our Medical Market Page, and our 2024 and 2025 Article Archive. 

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