Ⅰ. What is electromagnetic radiation？

When we talk about electromagnetic waves, we're talking about how much convenience they bring to our lives, especially in the age of 5G and the Internet of Everything. Our mobile phones, computers, iPads, and children's watches are the best examples of electromagnetic wave applications, and they're also the electromagnetic waves that are closest to us. When electromagnetic waves are given a new name, however, everyone may become uneasy. Electromagnetic waves are, in reality, a type of electromagnetic radiation. The word "radiation" stands out in particular. Students who have seen the American television drama Chernobyl must be afraid of the enormous harm that nuclear radiation causes.

Ionizing and non-ionizing electromagnetic radiation are the two types of electromagnetic radiation that exist. Electromagnetic radiation, in a broad sense, covers a large frequency range and wavelength distribution, ranging from tens of meters for longwave radiation to a few angstroms for gamma rays. Radio waves and microwaves, which are utilized in television transmission and wireless communications, as well as ultraviolet, infrared, visible light, X-rays, and gamma rays, are all examples. Ionizing radiation can extract electrons from an object's atoms, modify the object's chemical structure, and cause direct damage to cells in biological matter, whereas non-ionizing radiation cannot. Ionizing radiation includes things like UV, X-rays, and gamma rays. Fortunately, the radio waves and visible light to which we are most exposed in our daily lives are non-ionizing radiation, which is less damaging to human health. We can't, however, turn a blind eye to what's going on.

Ⅱ. What are the health risks associated with mobile phone radiation?

As indicated in the graphic below, the article "Cell phones: Modern Man's Nemesis?" details the forms of damage that mobile phone electromagnetic radiation can bring to the human body:

The cardiovascular system is harmed.

In a 1998 experiment, Braun et al. exposed human volunteers to RF-EMW at 900 MHz for 35 minutes and found elevated blood pressure (systolic and diastolic). Due to vascular depletion, blood pressure increased by 5°10 mmHg, accompanied by a considerable drop in capillary perfusion.

Harm to sleep

Despite finding no significant changes in sleep quality in an experiment conducted by Huber and others in 2000, exposure to 900MHz electromagnetic radiation for 30 minutes will greatly increase the time it takes to fall asleep and cause insomnia for a long period.

Affect neurohormonal secretion

Increase the probability of cancer

One of these is the carcinogenic potential of mobile phone radiation, which has been the subject of numerous research undertaken by various organisations. Hardell et al. (2006) conducted a study based on epidemiological questionnaires in response to public concern that cell phone exposure may cause cancer, and found that astrocytoma (grade III-IV) and acoustic neuroma do show a positive link with mobile phone usage.

There was a woman with multifocal breast cancer in one case. This is odd because she has never had a history of cancer. Despite the fact that this is still a possibility, her doctor observed an unusual pattern in her cancer cells. I examined it more closely and saw that it was the outline of her cellphone. They are perplexed by this. The woman, on the other hand, claimed that she frequently slips her phone in her bra. As a result, they will be able to connect the dots between her cell phone and her cancer cells.

Affect male fertility

Many reports on the impact of mobile phone electromagnetic radiation on the male reproductive system have yet to be clarified. But, do you think you've got what it takes to carry out this experiment? A study of 150 males who had worn their phones on their belts for a long time was conducted in 2009. Scientists discovered that the bone mineral density of the pelvic bone on the side where the phone was carried was lowered in these males.

Ⅲ. Why the weaker the signal, the greater the mobile phone radiation?

Why can't our cell phones communicate wirelessly? The fundamental reason for this is that your mobile phone can communicate with the base station, which then sends your signal to the mobile phone you want to call.

The downlink signal sent by the mobile base station to your mobile phone and the uplink signal sent by the mobile phone to the mobile base station is the two types of electromagnetic radiation involved here. In other words, when we make a phone call, we are exposed to two types of electromagnetic radiation: the base station's radiation and the mobile phone's radiation. Everyone may be more concerned about the base station's radiation, hence there have been many incidents of the base station being demolished in the cell. After all, life and health are the most important considerations. I was terrified when I saw this object above my head.

First, let's discuss the base station's radiation. The average power of a single channel in a modern 5G base station is roughly 5 watts, and it is 320 watts under 64 channels, which is about 55 dBm. It appears to be extremely enormous, however since electromagnetic wave path loss is equal to the square of the distance,

The distance is d, the frequency is f, and the speed of light is c. The path loss is proportional to the distance and frequency traveled.

Let's see how much radiation a 5G base station operating at 2.6G has on us under perfect conditions, using the route loss model above. Based only on free-space path loss, the following is an optimum power value. We can observe that even if the distance between the base station and the human body is only 10 meters, only 0.2 milliwatts of base station radiation reaches the human body.

In fact, 5G base stations emit significantly less radiation to the human body. According to China Telecom, the power and radiation of 5G base stations are intrinsically low, and they are within the state's safety parameters. Within 10 meters of the 5G base station, the current observed radiation is at 1-1.5 uW/cm.

However, because the distance is shorter, the influence of mobile phones on the human body is considerably larger. Many people currently wear their cellphones on their bodies at all times and in all places. According to the current 5G mobile phone transmit power standard, power level 3 in the Sub6G spectrum is 23dBm; power level 2 is 26dBm; power level 1, the potential power is bigger, and there is no specification yet, according to the definition of 3GPP. Currently, commercial use of 5G is mostly centered on the eMBB service provided by mobile phones operating in the Sub6G frequency band. The following will mostly focus on this scenario, dividing the mainstream 5G frequency bands into six categories (such as FDD n1, n3, n8, etc., and TDD n41, n77, n78, etc.). To explain.

5G FDD (SA mode): The maximum transmit power is level 3, which is 23dBm;

5G TDD (SA mode): The maximum transmit power is level 2, which is 26dBm;

5G FDD + 5G TDD CA (SA mode): The maximum transmit power is level 3, which is 23dBm;

5G TDD + 5G TDD CA (SA mode): The maximum transmit power is level 3, which is 23dBm;

4G FDD + 5G TDD DC (NSA mode): The maximum transmit power is level 3, which is 23dBm;

4G TDD + 5G TDD DC (NSA mode): The maximum transmit power defined by R15 is level 3, which is 23dBm, and the maximum transmit power supported by the R16 version is level 2, which is 26dBm.

That is, the worse the mobile phone's signal, the more power that must be transmitted, and the aim of communicating with the base station has been accomplished. This implies that when the signal is weak, your phone's full power is used, which is around 26dBm, or 398 milliwatts, or nearly 1000 times the radiation of a 10-meter base station. According to telecommunications tests, the mobile phone's standby radiation value is about 17.1 microwatts/square centimeter, and it is about 93.1 microwatts/square centimeter during a call. The worse the signal and the higher the radiation rating during a call, the further the phone is from the base station. So, if you're truly scared, instead of destroying the base station, you might as well shatter your phone.

However, rest assured that even when the phone's power increases, its radiation remains inside acceptable limits. Many professionals in the local communications business have indicated that my country's mobile communications base station radiation requirements are compliant with IEC, EU, and US standards; yet, Japan's regulations are 12 to 15 times higher. The reason for this is that selecting base stations in the aforementioned countries and locations is extremely challenging. The base stations offer a wide range of coverage and high transmit power. The United States and Japan are 600 microwatts/square centimeter, the EU is 450 microwatts/square centimeter, and China is 40 microwatts/square centimeter, according to mobile communication base station radiation standards issued by various countries.

In actuality, the base station's radiation is significantly lower than the Chinese requirement, as well as European and American standards. At the same time, 5G base stations are denser, with lower transmit power, higher frequency, and increased propagation loss for each base station. The observed radiation within 10 meters of the 5G base station is roughly 1-1.5 microwatts/cm2, according to actual measurements. The transmit power will be reduced adaptively for terminals close to the base station.

Not only that, but the base station's radiation level is lower than that of many common household equipments. A microwave oven with a reasonably high radiation dose emits 268 microwatts per square centimeter at a distance of 1 meter, yet China's standard for base station radiation emits only 1/6 of the microwave oven radiation.

As a result, the base station isn't terrible. The radiation sources that surround us should be given more consideration.