Tag Archives: Microwave

SocioNext MN87900 is a Single-Chip 24 GHz Radio Wave Sensor for the Internet of Things

The Socionext MN87900 from Socionext is a powerful and low-power single-chip microwave sensor at 24GHz with sophisticated sensing capabilities like motion detection, speed and direction detection and so many, that can quickly find applications in the Internet of Things sensing applications.

Socionext MN87900

Unlike PIR sensors like the popular HR-SR501 that can detect motion to about 3 meters at about 120 angles and based on the concept of detecting infrared energy emitted by an object while attempting to determine if it’s a motion or not, the Socionext MN87900 is a microwave sensor that sends out microwave signals and detects the bounce back signals to decide if it’s a motion or not. Microwave sensor uses what we call the Doppler’s Effect concept.

SocioNext MN87900 is a 24 GHz and very tiny, measures about 12mm x 7mm x 1mm making it ideal for the small size requirement in the most Internet of Things application and other applications in the areas of smart-home, automotive or driver assistance systems, medical applications, and many more. Based on a single-chip radio frequency IC (RFIC) that offers a multi-mode sensing capability for detecting stationary or moving objects and measuring the distance and direction of movement, including whether an object is approaching or leaving. This multi-mode sensor capability gives the device ability to re-adapt its functionality to different case scenario without making any single hardware changes.

The RFIC can be used to sense very slow movements (like breathing and heartbeats), and even detect the movement of multiple objects within a 160-degree radius to a distance of about 8 meters away. With slight modification, the RFIC can reach a range of up to 30 meters.

Apart from having powerful sensing capabilities, it is also power friendly. During continuous operation, the sensor can take up to 500mW, but this can be reduced to an intermittent operation where for example, during a one-sixth burst, the sensor can take about 80mW, a very drastic reduction in power. The MN87900 can pass through fabric or resin like materials, and unlike camera-based people detecting applications, the MN87900 doesn’t need to capture or display images to identify people or objects which is handy for privacy-concerned applications.

The MN87900 supports SPI as a form of interface to microcontroller system. Along with the hardware, a simple API system was developed to support the designs of CW, FSKCW, and FMCW mode capabilities to provide distance, direction, and relative velocity.

The following are the SocioNext MN87900 key specifications:

  • Sensing Modes – CW, FSKCW, FMCW (moving or stationary)
  • Detection
    • Motion direction – approaching or leaving
    • Motion speed – up to 200 km/h
    • Range – 0.15 to 8 meters 80°@-3dB, expandable to 30 meters
  • Variable frequency width –  24.15±0.1 GHz
  • Host Interface – SPI
  • High sensitivity – -110dBm
  • Transmission Power: 0.8mW
  • Fast frequency pull-in: 100 µs
  • Automatic adjustment: Built-in initial adjustment function (e.g. adjustment of RC filtering)
  • Power supply voltage: 2.5V
  • Current consumption: 200mA
  • Module size: 12mm x 7mm x 1mm
  • Weight – 145 mg
  • Temperature Range – -40°C to 85°C

The module pricing is currently not available, and more information about the product can be found here.

Teardown and experiments with a Doppler microwave transceiver

Kerry Wong did a teardown of Microsemi’s C900502 X-band planar transceiver:

I got a couple of Microsemi’s C900502 10.525 GHz X-band Doppler radar motion sensors a while ago. This batch was made in UK and had “UK patents 2243495 and/or 2253108 apply” printed on the case. I have seen a teardown of an HB100 Doppler radar module before and was wondering if I this one is any different inside.

Teardown and experiments with a Doppler microwave transceiver – [Link]

Teardown & Repair of an Agilent 53152A 46GHz Microwave Frequency Counter

Teardown & Repair of an Agilent 53152A 46GHz Microwave Frequency Counter – [Link]

On-Chip Microwave Laser

Lasers are everywhere these days: at the checkout in the supermarket, in the CD player in the lounge – and quantum researchers need them to test qubits in the (future) quantum computers. For most applications, today’s large, inefficient lasers are a perfectly adequate solution, but quantum systems operate on a very small scale and at extremely low temperatures. Researchers, for the past 40 years, have been trying to develop accurate and efficient microwave lasers that will not disturb the ultra-cold and fragile quantum experiments. A team of researchers from the Dutch Technical University Delft have now developed an on-chip laser, which is based on the Josephson-effect. The resulting microwave laser opens the door to applications where microwave radiation with a low loss is essential. An important example is the control of qubits in a scalable quantum computer.

Lasers emit coherent light: the line width (the color spectrum) can be very narrow. A typical laser comprises a large number of emitters (atoms, molecules or charge carriers in semiconductors) in a oscillator cavity. These conventional lasers are generally inefficient and generate much heat. This makes them a challenge to use in low-temperature applications, such as quantum technologies.

The researchers constructed a single Josephson junction in an extremely small superconducting oscillator cavity. Here, the Josephson junction behaves like a single atom, while the micro cavity behaves like a pair of mirrors for microwave light: the result is a microwave laser on a chip. By cooling the chip down to ultra-low temperatures (less than 1 kelvin) a coherent beam of microwave light is generated at the output of the oscillator cavity. The on-chip laser is extremely efficient: it requires less than one picowatt to produce laser radiation.

The research paper can be read here.

Source: Elektor

Teardown and analysis of microwave (26.5GHz) electro-mechanical step attenuators

Teardown and analysis of microwave (26.5GHz) electro-mechanical step attenuators from The Signal Path:

In this short episode Shahriar takes a close look at a pair of Hewlett Packard microwave electro-mechanical step attenuators operating up to 26.5GHz. Mechanical attenuators offer excellent repeatability, low insertion loss and nearly limitless linearity. The teardown reveals that the construction of both modules is very similar on the microwave path. In fact, the lower-frequency model still uses the same attenuator components. The newer model employs electronic control circuity while the older generation attenuator uses purely mechanically controlled DC path. Both models use a solenoid style actuators for step attenuation control.

Teardown and analysis of microwave (26.5GHz) electro-mechanical step attenuators – [Link]

Tutorial on High-Power Balanced & Doherty Microwave Amplifiers

Tutorial on High-Power Balanced & Doherty Microwave Amplifiers [Link]