Why the standard use at microwave components is set to about 2.45GHz?

Hi everyone,

Does anyone knows why the standard use at microwave components is set to about 2.45GHz? What are the advantages of this set which made it to be the industry standard?

I would appreciate every idea and answer even if you dont sure you know the exact reason.

10x in advance

i don't understand ur question , what do u want to know ?

khouly

Hi Khouly,

I will contact you !.

Paul.

Nightwish this is for you:

OK, please see wiki: http://en.wikipedia.org/wiki/Microwave_oven and you know why. !....

Hi,
What do you mean Nightwish?

wow you replied quickly

I will explain my question once again.

I had a job interview where I've been asked by the interviewer to explain why 2.45 GHz is an industrial standart? Why so many components, such as microwave oven and some wireless communication systems use this frequency?
I Answered him that it has a thing with the cutoff frequency of the waveguides in the system but it didn't satisfy him.
I also told him that the microwave oven uses 2.45 GHz because its magnetron and than he asked me why not to create a magnetron at 3 GHz or 5 GHz.

In other words, when you design a microwave system, what is the advantages of using a work frequency of 2.45GHz over other frequencies, say 3 GHz or 5 GHz ?
I guess it depends on the system requirements but what requirements make you use this work frequency?

Hope I made myself more clear

10x in advance

It is because the absorption for water is maximum for frequencies about 2.45 GHz.

@ Jone: This is NOT true, please read the Wiki link I posted before. Many people think this and they are all wrong !. Water is having its optimum at about 20 GHz and not 2.45 GHz.

OK. The reason they all use 2.4 GHz for wireless communication is simply because its the only world wide frequency that is common in ALL countries with almost the same specifications(Power and bandwidth). This is due to the fact that microwave ovens use it and therefor they excluded the frequency from official planning and mode it open to all to use on a serve best condition.

5.2 - 5.8 GHz is not open in all countries and has been made open in the last few years by relocating radar systems to other frequencies. Like in France etc...

Paul.

Yes, some further investigation showed that I was wrong. First of all, the dielctric loss depends on the temperature. According to the following site (figure 1)

http://www.lsbu.ac.uk/water/microwave.html

0°C food has maximum absorption at 8 GHz, and for 20°C it is about 20 GHz (as you said PaulHolland. The reason for chosing a lower frequency is that we don't want the food to absorb all the power at the surface. This will allow power to penetrate deeper into the water and thus heating it more evenly. Have a look at the page, there are some nice graphs.

ok I understand it better now, thank you all

Because the 2.45GHz is ISM (industrial, scientific and medical ) frequency?Ur not being charge for using that particular bandwidth.