In this tutorial, we are going to learn about RF (Radio Frequency) and Its Uses.
RF (Radio Frequency) –
- Its refer to energy which frequency is high enough to radiate , which has range between about 20Khz to 300Ghz.
- RF can also be conducted through cables / conductor like as cable television signals and between circuit components.
- The frequency of an RF signal often depends on the application.
Uses of RF:
- Most common use of RF is to transfer information without wires.
- To transfer information, we change something about the field we are generating this is called modulation.
- In Morse code, we turn the RF on and off.
- In amplitude modulation (AM), we change the strength of the RF.
- In frequency modulation (FM), we change the frequency of the RF.
- Most modern technologies use more complicated modulation to send digital information (Wi-Fi, cellular etc)
Below are the devices which are working on transfer information.
- Broadcast TV
- Cable TV
- Satellites / GPS
2. Sensing with RF
- RF can be used to sense objects like transmit RF, see what comes back.
- Most common example is radar.
- Other common examples, Body scanner and motion detectors.
- RF can also be used to measure materials.
Below are the devices which are working on sense / detect objects.
- Body Scanners
- Materials measurement
Heating objects with RF:
- Microwave Oven
- Inside a microwave oven, RF is generated by a magnetron; Frequency is 2.45 GHz, about the same as Wi-Fi.
- RF penetrates food or liquid, causing molecules (especially water) to vibrate.
- If metal is in the microwave, the radiated RF can turn back into conducted RF (electricity), causing sparks, fires etc.
- RF is often used for heating in industrial applications like as pasteurizing milk.
- Can be used for medical application.
Aside: RF safety
- X- rays, gamma rays, and UV are ionizing radiation like it can break up atoms / molecules (including DNA) cause cancer etc.
- RF energy is non ionizing radiation, it does not break atoms / molecules apart.
- RF is not dangerous under normal conditions, only very high power transmitter require caution.
RF Test and Measurements:
- Used by people who design, test, manufacture and debug devices that use RF.
- Basic categories of RF instruments:
- Spectrum analyzer
- Signal generator
- Network analyzer
- Power sensors