The ideal antenna is sitting isolated from any other electronics. But this is obviously not the case for most real designs. For wearables in particular, the human body is a challenging addition to your antenna’s operating environment. If you’re building a connected wearable, you need to talk to AntennaWare.
Following yesterday’s antenna-related content, ipXchange’s discussion with Matthew from AntennaWare at Hardware Pioneers Max 2024 seemed like a great shout for exploring the antenna requirements for wearable devices. Having won an Embedded Award, this innovation is certainly worth a look.
AntennaWare has a history in academic research regarding how electromagnetic waves interact with the human body. This is obviously very important when it comes to designing antennas for wearable devices as the human body drastically changes the electromagnetic waves from the ideal ‘on-bench’ testing scenario.
The challenges of placing antennas near the human body
Matthew highlights three main issues when placing an antenna near the human body, all of which will cause deviations from the ideal antenna performance if not accounted for. These are:
- Near-field detuning – the body changes the effective shape of the antenna and takes the resonant frequency away from the ideal, meaning lower transmission/receiving power.
- Energy absorption – human tissue is a (relatively) good electrical conductor, and this dulls the effective transmission power of the antenna.
- Body blocking – for multiple-wearable setups, the body shields devices from each other and even creates nulls where the received power is zero, due to destructive interference between reflected RF waves.
It is AntennaWave’s patented technology which helps them to create better antennas where RF interactions with the user are taken into account for best performance. In the simplest terms, AntennaWare’s devices send signals around the body, rather than through it. This allows devices on the chest and back to seamlessly communicate, without having to worry about absorptions and nulls.
Applications and protocols
Typical wearable applications that AntennaWare specialises in include healthcare, audio devices, industrial IoT, and sports equipment. By trying to compensate for the issues outlined above, AntennaWare improves the performance of RF devices used near to the human body.
AntennaWare’s off-the-shelf product range covers several radio protocols: 2.4 GHz, 1.9-GHz DECT, and UWB (Ultra-WideBand) at 6.5-8 GHz. For UWB, AntennaWare is using this technology mainly for data communications rather than real-time localisation.
The spread-spectrum nature of UWB technology also makes it good for security applications, and the low latency makes it even better for audio and AR/VR applications. For the latter, it is essential that head movement is tracked with minimal delay to visual prompts to lessen or avoid motion sickness, for example.
Evaluating AntennaWare
AntennaWare produces a few antenna evaluation boards in conjunction with its partners. That said A-B comparisons using samples on test designs – with all other components, including the human, in place – is the best way to truly evaluate the RF performance. AntennaWare can also create custom antennas for difficult transmission requirements.
Head to our user-defined board page – following the link below – to get connected with AntennaWare for a project. As always, specify your requirements, and ipXchange will put you in touch for consultation. Check out our wearables section for lots of other interesting components for your BOM.
Keep designing!