When it comes to mobile phone antennas, many young people may have no concept, while the older generation, especially those born in the 1970s and 1980s, must remember the protruding antenna on the "mobile phone".
So where does the antenna go now?
First of all, cell phones communicate through electromagnetic waves, which are emitted by the cell phone antenna, which has always been there, but in a different form.
Secondly, the wavelength of the electromagnetic wave emitted by the antenna is related to the size of the antenna.
In the old 1G era, the communication frequency band was 800MHz and the wavelength was 37.5cm. The length of a unipolar antenna was 9.375cm, a quarter of the wavelength, which was much longer than the length of the fuselage, so it had to be exposed.
With the continuous progress of communication technology, the frequency band is increasing and the wavelength is getting shorter and shorter.
In the 5G era, the communication frequency band has been increased to at least 3GHz(millimeter wave higher) and the corresponding wavelength is 10cm, so the antenna can be shortened to 2.5cm and easily hidden in the fuselage.
At the same time, the manufacturing process of phones and antennas themselves is improving.
The earlier antenna was printed in the fuselage circuitry and was called the FPC antenna.
Later, to make room for batteries and other components,A laser is used to carve an antenna, called an LDS antenna, onto the plastic back of the phone.
As shown in the above two mobile phones, the left side is the printed FPC antenna, and the right side is the LDS antenna.
The antenna can also be built directly into the metal case. For example, in the design above (recognize which phone?), the antenna is integrated into two metal frames on the side of the phone, one for Bluetooth, Wi-Fi, GPS, and the other for phone calls.