Part a: Explain the effect of the electromagnetic waves at three different frequencies on human beings. The frequencies are 5 GHz, 18 GHz, and 43 GHz. Explain the effects in terms of the transmit power, distance, and antenna radiation pattern. Also, provide examples from the real world in order to support your claims.
Solution:
Electromagnetic Waves are created by the movement of electrically charged particles. These waves are even named Electromagnetic Radiations who have higher frequencies on the other end the electromagnetic wave which has fewer frequencies are named Electromagnetic Field.Â
And on the grounds of these low and higher frequencies, we separate them into ionizing and non-ionizing radiations.
Ionizing Radiation (e.g., X-rays, etc) are excessively high frequencies and extremely dangerous for humans ever these can harm human DNA and also cause Cancer.
While on the other end non-ionizing radiations e.g., radio frequencies, microwave fields, etc are part of the electromagnetic spectrum and even dangerous for people especially children.
If they employ such technologies addictively which are in this field of frequency for example Mobile Phone (450 and 2700 MHz). We can name non-ionization radiation as a slow poison for a human being.
A mobile Phone, Transceivers, Radar, etc which are related to radiofrequency (100 kHz < f <= 300 GHz) generates various diseases in humans e.g., restlessness, eyesight weakness, headache, etc.
Besides, when we talk about large frequencies e.g., 5 GHz, 18 GHz, or 43 GHz which are more than mobile phone frequencies are very dangerous for humans. Disclosure to extremely high RF intensities can cause in heating of biological tissues as well as an increase in body temperature.
Tissue harm in humans could happen during exposure to large RF levels because of the body’s incapability to cope with or disperse the extreme heat that could be generated.
Despite all frequency recreates an essential role in communications. When we talk about large frequency ranges (means larger bandwidth frequencies), then more multipath is present which creates an issue called noise, e.g.,
So, to reduce noise or less multipath we required a lower frequency range.
Talking about the distance, as well as transmit power; if the distance or length of any signal raises its means weaker the signal is.
While reducing in distance means larger the receive power according to the relation:
Pr ∞ 1/d2
While increasing the received power will also raise the transmit power according to the relation:
Pr = (Pt * Gt * Gr * λ2) / (4 * π * d)2
And if transmit power is increased then SNR (Signal to Noise Ratio) will also increase as:
SNR = Pt / N
Increasing SNR means better communication.
An SNR of any signal is raised if Pt = ∞ or N = 0.
Despite it’s an ideal case. In reality, it’s not feasible. Even rising of SNR means the throughput or the Power of channel even rises according to Shannon Equation:
C = B log2 (1 + SNR)
Altering the frequency will even alter the size of the antenna which instantly affects the radiation as well as the impedance of an Antenna.
According to relation λ = c / f; the higher the frequency will reduce the λ (wavelength) which decreases the size of an Antenna.
In increasing or decreasing the size of an antenna the amount of radiated power/energy will alter differently points and therefore patterns will be changed or affected.
Antenna radiate established on the current distribution on the element.
For example, in a dipole antenna, the current allocation on the antenna alters relying on the length which results in various radiation patterns.
However in altering the size of the antenna, the current arrangement is not identical, thus the far-field pattern of an antenna may be altered accordingly.
Part b: Suggest some remedies in order to mitigate the harmful effects if any.
Solution:
As sources of RF radiation are so familiar in the modern world, there is no way to fully avoid exposure to it. There are some methods you can reduce your exposure to RF radiation, such as:
1) Avoiding jobs with raises RF exposure.
2) Reduce the time you spend around appliances, equipment, and other devices (such as Wi-Fi, Routers) that give off Radio-Frequency radiations.
3) Reduce the time you spend with cell (mobile) phones positioned against your ear (or near to another part of your body).
4) Turing off your cell phones or keeping away your mobile phones at night from yourself.
5) Purchase filters for electrical outlets.
Still, it is not clear that doing these things will be helpful in terms of health risks.
