As communication technology has grown. wireless radio frequency (RF) circuits have been used in more and more places. like in cell phones and Bluetooth products. RF circuits are at the heart of radio propagation. In recent years, the slow spread of 4G and the clear increase in the amount of data. that transferred have made PCB design of RF circuits more difficult.what is RF radiation? After all, the number of signals sent through an RF circuit goes up by hundreds each day. Also, since RF circuits more in small, portable devices. the basic requirements for the whole circuit are a small volume, even and reasonable routing. and no interference between the micro components. Still, it seems like electromagnetic interference between parts inside mobile phones is unavoidable. Don’t be afraid. There are some things that to reduce the effect of electromagnetic interference. This article will help you come up with a good PCB design for an RF circuit. This design has a small size and a clear ability to block interference.
What is the basis of RF radiation? Where is the RF broadcast used? Our article titled RF Publication: Regulations – What is Environment and Power Transmission, in which we seek answers to these and similar questions. Let us start.
Let us see how did transmit maximum power from amplifier to antenna. and how we can measure that power using an oscilloscope.
RF technology makes it easier to disrupt wireless communication. Radio waves can work through the air and use by anything. including those who, deliberately or accidentally, transmit signals that could describe interference.
First of all, it cannot “destroy” or “damage” radio signals that were before transmitted. But, the environmental impact may be equal to destroying an original signal. extract important information contained in that signal.
In other words, information still exists. but it practically ceases to exist to a particular buyer. The RF design environment is a constant challenge. and the proliferation of wireless devices does not make the situation any easier. There are several ways to make a system environmentally resistant.
A significant portion of this interference is a result of non-communicating devices. that using identical load-bearing frequencies.
However, there is the deliberate intervention. This call congestion. The purpose is to broadcast a signal. that somehow prevents other wireless systems from maintaining successful communication. Interference is an essential tactic in modern warfare. and is a nuisance (or worse) in everyday life and is entirely illegal.
It may seem strange that initially, governments will regulate wireless transmissions. Can we enforce laws on something concrete as electromagnetic radiation? However, the jam example makes it clear that the absence of regulations will lead to severe problems.
Private and public organizations that want to use a part of the electromagnetic . spectrum must obtain permission from the FCC. This permission called the license. The exceptions for systems that limited and therefore unlikely to cause significant inconvenience.
If dealing with legal radio broadcasts, you need to know yours transmit power. Even if presented official regulations. effective range, or another kind metric. it supposes to determine the send power that can accept in these situations. and measure the power of the system or the antenna’s field strength at a distance. It is easier to get power than to try to measure accurately.
In RF and all other electrical circuits. the power dissipated by a component. it is equal to the voltage on that component multiplied. by the current flowing through the component. It can think of an antenna as just a conductor . and thus something with very little resistance.
A conductor can indeed have little resistance in DC. but an antenna has a significant input impedance at higher frequencies. in the antenna’s impedance at specific frequencies that we use that to transmit our RF signal. Also, we will need this information to estimate the amount of power supplied to the antenna.
We would not want a cable or PCB trace to resist 50 ohms in a typical digital or analogue circuit. Appears to be a very high resistance for something described as a conductor.
However, we are generally interested in voltage transfer in low-frequency circuits. We suppose that the voltage on one input pin is as close as possible to the voltage on the last output pin.
A low output impedance, low conductor impedance . and high input impedance required to achieve an excellent voltage transfer.
But, the output stage of an RF transmitter (or an audio amplifier), the goal is power transmission. We do not just want to move voltage from one device to another. We want significant currents flowing through the antenna . so there is plenty of electrical energy that can convert into radiated electromagnetic energy.
The maximum power transfer occurs . when the load impedance’s magnitude equals the size of the source impedance.
In the RF circuit, the amplifier’s output stage will usually have an impedance of 50 ohms. so that the antenna impedance must also be 50 ohms to ensure maximum power transfer.
In previous reviews, we explained why we could analyze an RF output stage. by connecting the power amplifier to a 50 oscilloscope input. as most RF systems base on 50 Ω impedance, so it will usually need a 50 Ω antenna impedance.
Of course, if everyone knows the circuit’s proper voltage and impedance characteristics. it can only calculate the antenna’s power. A SPICE simulator would be another useful approach. Yet, if these techniques are not practical. if someone wants experimental verification, it will need to use measuring equipment.
If anyone has a spectrum analyzer, use them all. It designs to provide precisely this kind of information. Spectrum analyzer is necessary. It can use an oscilloscope. Using the 50 Ω oscilloscope input, look at the signal’s RMS voltage and then calculate it as V2 / R with power R = 50 Ω.
Electromagnetic transmission is carefully regulated to reduce the problems associated with unintentional interference. Intentional intervention, known as jamming, is illegal in the context of public life.
In the United States, transmission devices must generally license by the FCC.
Unlicensed operation is possible under certain conditions associated with limited transmission power.
The achieve maximum electrical power transfer from an amplifier to the antenna. and the magnitude must match the output impedance of the amplifier size of the antenna’s input impedance.
Transmit power can determine by mathematical analysis or SPICE simulation. It can also estimated experimentally using a spectrum analyzer or an oscilloscope.
Today we are here with our article titled RF Publication: Regulations – What is Environment and Power Transmission. I hope it was helpful.
