Radar | What Is Millimeter Wave Radar

In recent years, millimeter wave radar, as a technology that has attracted much attention, has been widely used in autonomous driving, smart home, health monitoring, smart city, smart building and other industries. So, what is the charm of millimeter wave radar and what changes can it bring to our lives? In this article, we will learn what is millimeter wave radar.

Introduction to millimeter wave radar

Millimeter wave is an electromagnetic wave located between microwaves and light waves, with a frequency band of 30 to 300 GHz and a wavelength of 1 to 10 mm. Although our common 24GHz electromagnetic wave band does not belong to millimeter waves, its propagation characteristics are similar to millimeter waves, so it is often studied and used as millimeter waves.

Millimeter wave radar has the characteristics of wide frequency band, short wavelength, narrow beam, light weight, strong resolution and strong penetration. Compared with microwave, millimeter wave radar has high resolution, light and small structure. Compared with infrared and visible light, millimeter wave radar has stronger penetration, is less affected by climate, can detect normally in harsh environments such as rain, snow, storms, smoke and dust, and has the characteristics of all-weather full-time work.

These advantages of millimeter wave radar make it play an important role in missile guidance, car collision avoidance, helicopter collision avoidance, anti-terrorism security, millimeter wave medical treatment and other fields.

How millimeter wave radar works

Millimeter wave radar emits electromagnetic waves through an antenna, which produce reflected echoes when they encounter objects. By receiving the reflected electromagnetic wave, and carrying out amplification and signal analysis calculation, the distance of the object can be calculated, and the distance between the left and right of the object can be calculated by combining different azimuth angles. Using Doppler effect, the distance, speed, Angle and orientation of the moving object are calculated.

Application classification of millimeter wave radar

Guidance radar, fire control radar, this type of radar currently has some choice in the millimeter wave band the main reason is to improve the detection capability, reduce the size of the radar, reduce weight and volume, easy to integrate.

Target detection radar, this type of radar is mainly through mechanical/electronic beam scanning, to achieve the detection of the observation area of the target distance, speed and Angle, equipped with the corresponding data processing unit, can achieve the target identification (scattering characteristics), tracking and prediction (kalman filter, particle filter, etc.).

Millimeter wave Earth observation Radar, this type of radar is mainly millimeter wave Synthetic Aperture Radar (SAR), this type of radar mainly realizes earth imaging observation and obtains SAR images of the ground area.

Millimeter wave short-range detection radar, this type of radar mainly realizes the two-dimensional or three-dimensional imaging detection of targets within 2 meters, and the current band of this type of system is 30~37.5 GHz, and 94~200 GHz or THz band. For example, at present, the three-dimensional scanning radar of human security check in the United States airport realizes the detection and imaging of targets inside human clothes and outside the skin through millimeter wave instead of X-ray, so as to enhance security; There are also non-destructive three-dimensional detection of some special materials through 35GHz band radar or 94GHz and THz band radar.

Car radar: Install radar sensors on the car to achieve collision avoidance, automatic parking, pedestrian detection, etc. At present, the mainstream car radar is 24GHz radar, but it is limited by frequency band control, radio astronomy 5Km does not allow the use of this band radar and its large size (mainly due to the large size of the antenna). At present, 77GHz automotive radar is gradually being productized and equipped with some high-end vehicles. The main advantages of 77GHz automotive radar are the wider frequency band allocated, higher range resolution, smaller volume than 24GHz radar, and strong target detection capability. However, 77GHz radar has higher production and processing requirements, but at present, This issue is no longer an industry barrier.