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Kardian · Guides · How the radar works
How it works, in plain words

How a radar reads your breathing through the duvet.

Every breath lifts your chest by a few millimetres. Every heartbeat moves it by far less. A Kardian sensor sends out a tiny radio pulse, listens for the echo off your chest, and times it precisely enough to follow both, all night, without touching you.

A hand resting on the chest
The pulse

A tiny pulse, fifteen million times a second. Then listen for the echo.

Send

An impulse radar sends a very short radio pulse, centred near 7.3 gigahertz, fifteen million times a second.

Echo

The pulse reflects off the body. The time it takes to come back tells the sensor how far away the chest wall is.

Follow

As the chest rises and falls, the distance changes by millimetres. The heartbeat adds a far smaller movement on top.

Separate

Software separates the slow rhythm of breathing from the faster rhythm of the heart, and reads both.

It runs at more than a hundred times less power than a home Wi-Fi router.

Through bedding

Not all radars are the same. The frequency decides what it sees.

Higher-frequency radar is more readily reflected by a duvet, a pillow or thick clothing, so the echo can come from the blanket instead of the chest. Kardian's impulse radar, from 6.5 to 8.5 gigahertz, passes through a duvet, a topper and clothing to the chest wall, in any sleeping position.

A made bed with two pillows and a duvet in a quiet bedroom
When you are still

It reads you at rest. Thousands of times a night.

At rest, not on the move

Heart rate and breathing are read while you lie still. Turning over or getting up shows as movement and time out of bed.

The closest body

It reads the person nearest to it. Two in the bed: one sensor each, above each side. If it picks up two sets of vital signs, it pauses.

Range

Heart rate up to about 3 metres and breathing up to about 7, across a field of about 130 degrees.

No camera

There is no lens. Radar reads movement; it cannot see a face or a room.

No microphone

It cannot hear a word.

Inside the disc Peer-reviewed · FDA-cleared

Radar chip, antenna, processor. And years of published work.

The sensing has been tested against hospital references in peer-reviewed studies. In one, breathing rate came within about one breath a minute of a physician's count, on average, across 33 patients (Scientific Reports, 2019). The clinical XK300 is FDA-cleared (510(k) K202464) for measuring heart rate and breathing rate in adults, and has been used in hospitals and nursing homes since 2021.

Exploded view of the sensor: cover, circuit board and base

Kardian Somily is a separate general wellness product built on Xandar Kardian's radar technology; it is not the cleared device, does not diagnose, and is not an alarm. XK does not predict or diagnose health events.

Questions

About the radar.

How can radar measure heart rate without touching you?

Each heartbeat moves the chest wall slightly. The sensor times the echo of a radio pulse off the chest precisely enough to follow that movement, and separates it from the larger, slower movement of breathing.

Is radar safe in the bedroom?

Yes. The radar runs at more than a hundred times less power than the Wi-Fi router already in your home, and this radar technology has been used in hospitals and nursing homes since 2021.

Does it work through blankets?

Yes. The wavelength passes through a duvet, a topper and clothing, in any sleeping position.

Can it see me?

No. There is no camera and no microphone. Radar reads movement; it cannot see a face or hear a word.

How far away can it be?

Heart rate up to about 3 metres and breathing up to about 7 metres, across a field of about 130 degrees. Above the headboard, about 1.5 metres from the floor, is typical.

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