Plastic materials for 5G application _ Part1_understanding 5G
In different mobile communication eras, there are different requirements for polymer materials.
First of all, we will try to understand what is 5G and why it is so different.
Communication technology is not mysterious. As the most dazzling gem in the crown of communication technology, 5G is an evolution of existing communication technology.
All this should start with a "magical formula".
c=λ* V
c —the speed of light
λ —wavelength
V— Frequency
It is this super simple formula that contains the vastness and depth of our wireless communication technology.
Whether it's 1G, 2G, 3G, or 4G, 5G, it's all about this mathematical formula, and follow my steps to understand more about it.
Radio wave belongs to one kind of electromagnetic wave, and its frequency resource is limited. In order to avoid interference and conflict, we further divided the lanes of the radio highway and allocated them to different applications and purposes.
What is the frequency of 5G?
A few months before, the Ministry of Industry and Information Technology issued a circular to clarify the initial intermediate frequency bands of 5G in China: 3.3-3.6GHz and 4.8-5GHz.
Meanwhile, opinions are being sought in the high-frequency bands of 24.75-27.5 GHz and 37-42.5 GHz.
At present, 28GHz is mainly used in international experiments (this frequency band may also become the first commercial band of 5G).
If we calculate it at 28GHz, according to the formulas mentioned above:
λ=c/V=300,000,000(m/s)/28,000,000,000(Hz)≈ 10.7mm
Well, this is the first technical feature of 5G.——Millimeter-wave
Since frequency is so good, you must ask, "Why didn't we use it before?"
The reason is simple - it's not that you don't want to use it, you can't afford it!
A remarkable characteristic of the electromagnetic waves is that the higher the frequency (the shorter the wavelength), the closer it tends to propagate in a straight line (the worse the diffraction ability). Moreover, the higher the frequency, the greater the attenuation in the propagation process.
Small power scheme
The smaller the base station, the bigger the number, the better the coverage and the faster the speed.
Where is the antenna?
Did you find that most of the old cellular phones used to have long antennas, and the early mobile phones also had small antennas, why can't we see the mobile phones with antennas later?
Some people say that because the signal is good, no antenna is needed.
It's not true. No matter how good the signal is, there must be an antenna. The main reason is that the antenna is smaller.
According to the characteristics of the antenna, the length of the antenna should be proportional to the wavelength, about 1/10~1/4.
Millimeter-wave, the antenna also becomes millimeter level, which means that the antenna can be stuffed into the cell phone. This is another feature of 5G, MIMO. MIMO is Multiple-Input Multiple-Output, which means multiple antennas for transmitting and multiple antennas for receiving. MIMO has already existed in the LTE era, and 5G has continued to develop and become an enhanced version of Massive MIMO.