Tech world has been talking about 5G technologies for years. Ever since the conceptualization of 5G, signal transmission using millimeter waves is always under suspicion due to worries about health risks. Despite the fact that researchers do not have sufficient data about health risks of millimeter waves, it is a scary topic for many peoples which lead to ongoing discussions.
What are the unique features of 5G technology?
Since the first generation, cellular network use radio waves to transmit voice calls data bits from base station to the individual mobile devices and vice versa. In LTE (4G) and LTE advanced technology, each mobile device can support multiple frequency bands for various service providers across countries and regions.
Third generation cellular network were capable of sending and receiving internet mobile devices and the data rate has been significantly increased in 4G technology. 5G network will be capable of providing even higher data rate and low latency services with advanced network technologies. In order to achieve higher data rate, 5G uses much higher frequency spectrum, small cells, and complex modulation techniques.
1. Frequency Spectrum – 5G NR (New Radio)
Conventional 3G and 4G cellular networks transmit signals below 3.6 GHz of radio frequency spectrum. Due to bandwidth limitations, maximum data rate has limitations as well. 5G tests have confirmed that the technology is capable of achieving downlink data rate up to few gigabits per second.
Frequency spectrum used in 5G technology can be divided into three major bands such as Sub-6 GHz range, mid range and high range millimeter waves.
Sub 6-GHz spectrum: Frequency range below 6 GHz range is grouped under Sub-6 GHz category.
Millimeter waves: Frequency range above 24 GHz and below 100 GHz (for 5G applications)
Find applications of millimeter waves
Properties of millimeter waves
Highly distorted by atmospheric water molecules and Oxygen-induced atmospheric absorption
Due to extremely short wavelength, it cannot penetrate concrete walls and strong structures
Low interference from surrounding low frequency noise
Effects of millimeter waves on human body
One of the major characteristic of millimeter waves on human body is skin absorption. Exposure of EM radiation at millimeter waves will cause skin penetration (60 to 90 percentages in extreme cases) due to dielectric properties of human skin cells (during close exposure). However, researchers observed that the 30 to 40 percentage of the incident power will be reflected from skin.
Power of the transmitted signal and time of exposure are significant factor in this scenario.
Many researchers found that long term exposure to microwave and millimeter wave radiation are carcinogenic. Unfortunately, the impact may not be obvious in very short term but could cause serious damages to human cells over time.
Long term exposure of microwave and millimeter wave frequency radiation also could affect other living organisms and plants.
2. Large number of transmitting stations
Number of smart devices is growing in exponential rate every year. Small cell concept is one of the best ways to provide high data rate and low latency services. Hundreds and thousands of small cells will be deployed in 5G technology.
What are small cells in 5G technology
Increase in the number of base stations and cells cause increase in wireless noise. More transmitting antennas will be deployed across the streets, on buildings, lamp posts etc… Network operators will decide where to install new stations; individuals may not be able to control the locations of deployment.
Find: What are 5G frequency bands
Regulations and guidelines
Regulatory authorities like FCC has strict guidelines for electromagnetic exposure level in public places and industrial sites where employees exposed to regular EM radiation. However, the standards were created based on the first generation technology reference to military technology; it has not been updated much in 20 years.
According to experts, FCC standard was based on thermal effect of electromagnetic radiation (if the device does not heat body, it does not harm body). Biological effects of RF radiation over a long period of time on human body at different frequency ranges have never been studied.
Independent researches shows that long term exposure to microwave radiation could cause cancer in human body. In fact, it is hard to collect sufficient evidence to support this claim because conducting a test with direct exposure to human body has lot of limitations.
Regulatory bodies across the countries are monitoring exposure levels but telecommunication is a huge business, pays for costly frequency spectrum and lot of competitiveness. More innovative ideas emerging and service providers are competing each other to implement it first.
Military use of millimeter waves
Military uses high power millimeter waves in active denial systems to control attack enemies. Active denial systems (ADS) are biological weapon designed to crowd control by activating high power millimeter waves which heat up body during exposure. Highly directive antennas aim the target and disintegrate the crowd in seconds.
Final thoughts – is 5G safe?
We are going through a transition stage in wireless technology now, the existing LTE advanced technology will be migrated to 5G technologies by year 2020. At this moment, no one is certain about the impact of 5G technologies to human body. Besides from the strict regulation from monitoring authorities, it important to spread the awareness to public about the downside of high frequency radio waves to take necessary steps to safety.
Based on the research data from different sources, long time exposure to high power microwave and millimeter waves could cause serious damages to skin and brain cells. Technology offers us convenience and assistance to do more complex tasks, at the same time everyone have the responsibility to make sure it will not affect human being and other living organisms.
Source: Millimeter-wave interactions with the human body: state of knowledge and recent advances by Maxim Zhadobov, Nacer Chahat, Ronan Sauleau, Catherine Le Quement and Yves Le Dréan.
good night
thank you very much
my quastion how used milimeter wave antenna
Its is based on the Use of an Application, How you design an Application. mmWave is a broad spectrum.