RF Power Splitter

RF power splitter is an element of RF components. You probably saw these bellow pictures, and yes those are the splitters. We will start here with the basic and functional of splitter and how it works. We will not go in deep and details of its calculation or theory.

  In nature we can see an example of splitter on a river that has an obstacle, and splits into two. In this case, part of the water continues down a path, and another part by another way.
For the case of RF Power Splitter or RF Power Dividers, instead of water, it is the RF signal that is divided - in that case the input signal is 'divided': the form remains unchanged, but the 'power' is splitted. For this reason, the RF dividers are known as RF 'Power' Splitters. So the power out put of each way will be decrease and lower base on the number of how many way which it were divided.
In the following picture, we can see a simple illustration of a Splitter. The signal (represented by large red circles) goes in one side and out the other two (B) and (C).

So Basically, you know how the splitter or divider does.

And how and where we use this splitter or divider?
We will use splitters/divider when we need to split the signal in to 2 or more direction where we need the signal to the destination we want.

Imagine the following situation: a small rural community was considered by the RF planning engineer for installation of a new BTS. The point for the installation of the Tower has already been acquired: its on a small hill in the Center of 3 small regions, with good line of sight to all, as seen in the figure below.

Due to the low population for those 3 area, RF engineer decided to install only 2 cell (logical cell) and 3 sectors (3 physical antenna) to provide the signal coverage for those 3 region to do this RF engineer will use one a splitter device to splitter signal from one sector to other sector thus these 2 sector have the same logical of cell. This is good apply for cost saving and technical concept.

An important observation in the case above is that the cell that is 'NOT' divided (Blue in the figure) should cover the denser region, because that is what will have the greatest traffic. And the cell that will be divided will cover simultaneously the other 2 smaller regions (in green in the figure).

In addition, each of the two cells in green has half the power of the blue sector (considering the same transmitter power for each one). This 3 dB difference must be taken into account so there's no loss of quality, mainly in 'indoor' regions.

Anyway, this can be fixed through adjustments, if for example it is possible to increase the power of the transmitter. Will depend of course on how is the quality in the regions met – usually in cases like this, we don't have many losses in practice.

This is not the 'final solution', but it sure is the best action to take, considering the scenario above - cover all small regions. In the future, with the development and progress of each of these regions (and consequently greater use of telecommunications services) we will have then justifications for expansion of the third cell in BTS.

Well, we have seen how an RF Power Splitter/Divider works, and also a good example of its implementation.

But the dividers not only divide for 2 outputs. We have for example a splitter with 4 outputs. In this case, each output will be 1/4 of the original signal strength (remember that dividers always divide 'equally' the input signal between all outputs).

Note: one of the most important points when it comes to RF Dividers is the insertion loss, i.e. the loss that we've added to the system when we inserted such elements. The bigger the loss entered in the system, the lower part of the signal will arrive at your destination, which is bad.

So when we talk about that in a 4 outputs splitter will have 1/4 of the original signal strength on each output we're 'disregarding' the loss by inserting the component itself, and considering only the loss resulting from the division of signal (whose order of magnitude is much larger).

So in practice what are the losses that I have using the RF Splitter (splitter)?

Assuming NULL the loss by inserting the element (i.e. kept the characteristic impedance of the system), and taking into account only the loss by dividing the signal into more outputs, we have the following correspondence table of 'Number of Output Ports' x 'Power Level Reduction' in a Divider (splitter).

Another important information regarding RF Power Dividers (splitters) is about isolation, i.e. a signal should not interfere with the other. For this, it is important to know the characteristics of construction.

Its construction can be through the use of resistors or transformers, being these last used in examples like the above. But beyond our scope today, and later we'll explain in a simple manner its construction and operation, explaining in more detail how this isolation works.

For now, just know that all RF Splitter are passive elements, i.e. you don't need power.

Yet we are also NOT analyzing other aspects such as different frequencies or technologies. Let's first understand the most important aspects (main) in its simplest form. In the next series of tutorials let's gradually assimilating the countless possibilities of combination and use of such equipment.

At this point then we already know the RF Power Divider, we understand its basic operation and for what it serves, and we also saw a practical example of use.