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mmWave radar sensors – What is mmWave

mmWave is an extremely valuable sensing technology for detection of objects and providing the range, velocity and angle of these objects. It is a contactless-technology which operates in the spectrum between 30GHz and 300GHz. Due to the technology’s use of small wavelengths it can provide sub-mm range accuracy and is able to penetrate certain materials such as plastic, drywall, clothing, and is impervious to environmental conditions such as rain, fog, dust and snow. TI has two families of mmWave sensors, AWR mmWave sensors for automotive and IWR mmWave sensors for industrial, drones and medical applications.

mmWave sensors transmit signals with a wavelength which is in the millimeter (mm) range. This is considered a short wavelength in the electromagnetic spectrum and is one of the advantages of this technology. Indeed, the size of system components such as antenna required to process mmWave signals is small. Another advantage of short wavelengths is the high resolution. A mmWave system that resolves distances to wavelength has accuracy in the mm range at 76-81GHz.

Additionally, operating in this spectrum makes mmWave sensors interesting for the following reasons

  • Ability to penetrate materials: see through plastic, drywall and clothing
  • Highly Directional: compact beam forming with 1° angular accuracy
  • Light-like: can be focused and steered using standard optical techniques
  • Large absolute bandwidths: distinguish two nearby objects
  • Antenna-on-package integration enables smaller system size
Slow and fast FMCW

The transmitting signal can take form of different types of waveforms, including Pulsed, Frequency-Shift Keying (FSK), Continuous Wave (CW), and Frequency Modulated Continuous Waveform (FMCW). TI mmWave Sensors implement Fast FMCW for its robust operation, rapid sensing and reduced ambiguity in dense scenes. Fast FMCW is also able to provide accurate measurement in both range and velocity of objects enabling TI mmWave Sensors to provide multi-dimensional sensing.

A complete mmWave radar system includes transmit (TX) and receive (RX) radio frequency (RF) components as well as analog components such as clocking, and digital components such as analog to digital converter (ADC), micro controller unit (MCU), and Digital Signal Processor (DSP).

Texas Instruments (TI) has solved these challenges and designed CMOS-based mmWave radar devices that integrate the components.