5.8G microwave radar sensor human body detection radar sensor

5.8G microwave radar sensor human body detection technology radar sensor, 5.8G microwave radar sensor technology, as a special distance/displacement measurement method, can solve the measurement problem of short-range targets, so it is also called short-range radar. It has expanded from the military field to the civilian field, and has been applied to position measurement, person recognition, speed measurement, environmental monitoring, displacement monitoring, etc.

Compared with other human presence detection technologies, 5.8G radar sensing technology has unique advantages such as non-contact, rainproof, fogproof, dustproof, etc., and has gradually become an important sensing method in the field of short-range target displacement measurement.

Radar sensors have a variety of sensing technologies. According to the difference of radar emission signal, radar can be roughly divided into two categories: single frequency radar and broadband radar. The emission signal of the single-frequency radar is a single-frequency microwave continuous wave signal (CW), also known as Doppler radar, which is suitable for the measurement of target velocity and high-precision displacement.

The transmitted signal of wideband radar has a certain bandwidth. Broadband radars can be classified into pulsed ultra-wideband (IRUWB), linear frequency modulated continuous wave (FMCW), and stepped frequency continuous wave (SFCW) according to the different radar signals. Compared with the CW radar, the wideband radar has the ability of multi-target resolution and can simultaneously complete the multi-target measurement.

Although microwave radar is used to measure the distance between the measured targets of the radar host, the distance of the same target can be measured by multiple hosts, and the spatial three-dimensional coordinates of the measured target can be calculated using the known spatial position relationship between the radar hosts. , so as to achieve the spatial positioning of the target.

Due to the different emission signals of the radar, the measurement principle and structure of the radar system are also different.

CW radar systems are relatively simple. It only requires a single frequency microwave source. By intervening in the reflected signal and the transmitted signal of the target, the target velocity and displacement measurement can be completed, and high-precision measurement results can be obtained.

The IR-UWB radar completes the measurement of the target distance by measuring the target reflected signal pulse signal and the time difference between the target reflected signal and the transmitted signal. When the target moves, the target displacement measurement can be completed; when measuring targets at different distances, Complete multi-target resolution while satisfying radar pulse resolution.

FMCW radar regularly sends out microwave signals whose frequency varies linearly with time, mixes the echo signal reflected by the target with the transmitted signal, obtains the beat signal reflecting the target distance, and completes the target distance measurement according to the shooting frequency; when measuring different distances When the target is different, the shooting frequency corresponding to the target will be different, so as to complete the multi-target distinction.

SFCW radar is similar to FMCW. The difference is that instead of transmitting microwave signals whose frequency varies linearly with time, SFCW radars emit microwave signals whose frequency increases with time steps. After the radar receives the echo signal reflected by the target, it will interfere with the phase of all the step-frequency microwaves in the radar demodulation device, complete the measurement of the target distance, and complete the target displacement measurement according to the interference phase information.

The above four types of microwave radars have their own application research fields, involving many aspects of social needs, and also have their own characteristics.

CW radar has carried out more research on short-range high-precision displacement measurement, life signal detection, etc.;

The research of IR-UWB radar is reflected in indoor positioning, life signal detection, wall penetration detection, etc.;

FMCW radar has the characteristics of speed, distance measurement, intelligent transportation, spatial positioning, high-precision level measurement, target speed and so on.

SFCW radar has the advantages of multi-target recognition, high-precision phase displacement measurement, etc., and has been applied to structural monitoring.

Compared with the infrared sensor human body detection technology, the radar sensor has a longer sensing distance, wider angle and no dead zone. Unaffected by temperature, humidity, airflow, dust, noise, brightness and darkness. Strong anti-interference ability, can penetrate acrylic, glass and thin non-metallic materials to embed multi-digital filtering algorithms, with higher anti-interference performance.

Because the 5.8G microwave radar sensor chip integrates microwave circuit, intermediate frequency amplifier circuit and signal processing MCU, it has few peripheral components, high integration and good production consistency, which greatly reduces the overall size and ensures the performance of the sensor.

The 5.8G microwave radar sensor can be used in scenarios such as human presence detection or moving target sensing, including smart home, IoT, and smart lighting, especially in the home bathroom market, and can be used to realize the wake-up control function of lamps, which is widely used because of its cost-effectiveness. application.

The radar sensor can be configured with a sensing distance, and its sensing distance can reach 12 meters. The actual sensing distance can be flexibly adjusted according to needs.