Microwave Motion Detector ( Microwave sensor ) uses , features , cons and pros

Microwave Sensor

It is also called Doppler Radar , It is sensitive to the reflect microwave from the objects , without interference from temperature , It has the advantages of low power consumption , constant/pulse wave operation mode , There are three kinds of microwave sensors which are planar Micro-strip , Wave-guide & Coaxial .

Microwave motion sensors emit the continuously of microwave and receive the reflect microwave to detect the moving object , They are among others that relay signals to the alarms when they detect the motion and they emit microwave energy to detect a movement .

Microwave Motion Detector

Microwave Motion Detector

Microwave Sensor advantages

You know that Microwaves are the electro -magnetic radiations whose frequency ranges from 0.3 GHz to 300 GHz , These waves are mostly used for the non- broadcasting issues .

Unlike other waves , these waves have narrow beam that imparts it with the characteristic features like broad Bandwidth and high data transmission rate , These waves are used in the space crafts , the communication satellites and various other fields like TV , telephone communications and security systems .

Microwaves are used in the operation of various security devices , Microwave motion detectors are one of the motion sensors that detect the intruder’s motion into the specific portion and the triggers alarm as a consequence .

Microwave motion detectors emit microwaves into the specific region and they detect any intrusion by analyzing the received microwaves frequency after the reflection from the intruder .

The main guiding principle for almost all of these sensors has been the Doppler’s Effect , The microwave motion detector circuit mainly comprises of components which are the transmitter , the receiver and the alarm/related circuit .

The transmitter sends off the microwaves into the area , These waves have a specific frequency , as they strike with the intruder moving with a velocity , frequency and consequently , the phase of the wave signal gets altered .

When these reflected waves are received by the receiver , Its phase analysis is done and consequently , The alarm is triggered on if the analysis depicts some change in the phase of the wave signals .

Unlike other detectors , The Microwave sensors can be used in the harsh environment where the heat cycles are not regular , the microwave radiations can easily penetrate through the walls and holes , so , they can be used to impart security across the boundary/closings .

Microwave motion detectors are combined with PIR technology ( passive infrared detectors  ) to reduce the false alarms which we usually called as dual technology detection method .

Microwave is the wave which can not be interfered by the temperature , It can overcome the disadvantage of passive infrared detection technology , Microwave can penetrate the objects and it can prevent the damage of detector .

Microwave motion detectors disadvantages

Microwave motion detectors suffer from false alarms that occur due to the slight vibrations of objects such as curtain and swinging signs , They do not operate continuously , they work in intervals , So , there are large chances of any intrusion .

To combat this problem , The improved detector has been designed that contains all the components of a normal sensor along with two receiver/mixer diodes , Some of the detectors contain diodes that enable the detector to sense if the intruder is moving towards or away from the detector .

The detectors are helpful in sensing and differentiating between the ordinary movement and the intruder movement , This feature of such sensors make them highly reliable .

The special properties of microwave beams allow them to penetrate most types of surfaces in the area of detection shield , however metal is not among them , So , the sensor may detect the motion where detection is not desirable and not detect motion where it is desirable .

Although these sensors detect the motion through wood and most building materials , microwaves do not penetrate metals , Metal objects act as a shield that creates shadows or dead zones behind them , The areas where the sensor cannot detect the motion .

On the other hand , because the beam can penetrate the walls , the sensor will detect the motion behind the walls , even if such motion is normal , As the sensors are extremely sensitive to the motion .

They are also prone to the other false alarms , Everyday movements such as the objects blowing in wind may trigger false alarms , Even fluorescent lighting that emits detectable light particles , They can activate the sensor erroneously and they may trigger a false alarm .

Uses of microwave motion detector

Microwave motion detectors are used to detect the heartbeats and breathing rate of a human , They are used in monitoring the light system of a house or a building , They are used in the elevator shaft-way , They are used in the security issues and traffic law enforcement .

Since the development of microwave technology , The microwave sensors are used in the industry , traffic , the civilian electronic devices such as the speed measure of vehicle , the liquid level measure , the automation door , the automation light , the alarm system , reversing radar…etc .

Compared to conventional PIR motion detector , the motion detector with microwave sensor combination can provide more reliable performance , Microwave motion detectors are used for special guard places like Prison , Bank , Military warehouse , Museum , Transformer substation…etc .


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