Microwave sensors, also known as RF or Doppler sensors generate an electromagnetic field between transmitter and receiver, creating an invisible volumetric detection zone. In 1971 Southwest Microwave developed the industry’s first bistatic microwave sensor. Microwave sensors are easy to install, provides high probability detection, low noise and resistant to environmental changes.

 What is a Microwave sensor?

As the name implies Microwave sensors uses continuous waves of microwave radiation to detect motion. It sends out high radio frequency and measures the reflection of an object by sensing the frequency shift. Thus this type of sensor is more sensitive than many others. Their pulse cycles can be bypassed if you know the cycle pattern.

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What are the features of Microwave sensor?

The Microwave sensor applies the Doppler Effect to identify the moving objects using the microwaves. The microwave sensors operate at K-band frequency, maximizing the performance and minimizing the interference from external radar sources. Microwave sensor consumes more power making their operational costs slightly expensive.

How Microwave sensor works?

When an object is placed in the range of incident signal, the signals secure shown going back to the sensor the signal is slightly manipulated in terms of frequencies which intend to be Doppler shift. Whenever the frequency shift is observed by the sensor module, the circuit brings the frequency shift and original frequency together and emits two individual frequencies based on object position whether it is receding or contacting the sensor.

How the circuitry actually works?

The received device output signals should be amplified properly. So, as a result differential opamp circuit is used. The resonant circuit present over the module emits a signal on to the object and the reflected signal is sent back to the resonant circuit again creating differences in frequencies of the signals which results in a mixer circuit.

The output of the opamp should be correctly shutdown with the help of a relay level or an alarm for figuring out the imagined limitations. The below fig shows the pinout configuration.

(picture of pin configuration)

What are the benefits of Microwave sensors?

Intelligent security:

When a person enters the sensing area, the room automatically lit up, In security intelligence the sensor detects the temperature of body and compares with characteristic value in order to control the lamp. The delay time at the end of lamp automatically put out.

Anti-Interference signal:

We know that there exist a lot of frequency signals some signals may be similar to human body induction signals but with the help of microwave sensor we can identify the human body correctly.

Intelligent identification:

It can detect the day light so that the light will be lit up during evening. It can also be lit anytime based on climate changes.

Strong applicability:

It can be applicable to control load in ordinary suction lamp, fluorescent lamp, three-proof lamp, LED lamp etc.

Minimizing energy consumption:

The microwave sensor consumes less power i.e. less than 1w, which is considered to be best protection to the life of sensor.

Eco-friendly:

It emits a radiation power which is equal to 0.1 percent radiation of mobile phone so, people need not to worry about radiation.

Weighing Microwave sensor pros and cons:

Pros:

• Microwave sensor helps in energy conservation by saving 40% expenditure on electricity.
• Microwave sensor enable auto-dimming of light by saving energy.
• Microwave sensor can detect small movements hence they are sensitive.
• Microwave sensor cover wide range about 12 mts.
• Microwave sensor can detect the motion beyond the wall or a door.
• Microwave sensor have high immunity, high precision.
• Microwave sensor can be used in any environmental condition.
• Microwave sensor has avoided touch-switch control, panel switch control, voice control.

Cons:

• Microwave sensor prone to false alarm due to blowing of wind, penetration through walls etc.
• Microwave sensor due to high sensitivity can detect non-human objects such as animals, preys, moving particles etc.
• Microwave sensor cannot reach beyond metal obstruction.
• Microwave sensor is costlier than PIR sensors.
• As microwave radiation is harmful hence low power Microwave sensor are used.
• Microwave sensor consumes more power than PIR sensor.

Applications:

• In designing the tablets and capsules.
• In cheese production.
• In dishwasher to detect broken crocks.
• To measure water in oil.
• Monitor functions of conveyors belt.
• Monitor waste water and sewage levels.

Final words…

Therefore microwave sensors cover wide range than PIR sensors and are more expensive. It can also be vulnerable to electrical interference. If you are looking for a 24/7 professionally monitored environment then this sensor helps you out. Hope you liked the article. What are your thoughts on Microwave sensor applications? Let us know in comments.