Cell phones use frequencies in the microwave range, typically around 2.4 GHz and 5 GHz, which are similar to the frequencies used by microwave ovens[3][4]. Frequencies used by cell phones and microwave ovens are both in the microwave range of the electromagnetic spectrum, but they differ in terms of power levels and modulation. Microwave ovens typically use power levels in the range of 700-1000 watts, while cell phones use much lower power levels, typically around 2 watts or less[1]. Additionally, the microwave radiation used in ovens is unmodulated, while cell phone signals carry a wealth of information, including voice data and other signals needed to maintain a connection[1].
The frequencies used by cell phones and microwave ovens are both in the microwave range because this range of frequencies allows for the use of small, omnidirectional antennas for portable devices, such as cell phones and wireless LANs[3]. The short wavelengths of microwaves also allow for highly directional antennas to be made smaller and more practical than they would be at longer wavelengths, making them useful for broadcasting and telecommunication transmissions[3].
In summary, cell phones use frequencies in the microwave range, similar to those used by microwave ovens, because this range of frequencies allows for the use of small, omnidirectional antennas for portable devices and highly directional antennas for broadcasting and telecommunication transmissions. However, the power levels and modulation of the signals used by cell phones and microwave ovens differ significantly.
Citations:
[1] https://www.straightdope.com/21343255/how-are-the-microwaves-in-ovens-different-from-those-in-cell-phones
[2] https://www.physicsforums.com/threads/microwave-oven-vs-cell-phone.153532/
[3] https://en.wikipedia.org/wiki/Microwave
[4] https://www.tennessean.com/story/opinion/2021/09/30/microwaves-technology-smartphone-wifi-gps-bluetooth/5817676001/
[5] https://flexbooks.ck12.org/cbook/ck-12-middle-school-physical-science-flexbook-2.0/section/18.6/primary/lesson/microwaves-ms-ps/
