Any manufacturer, especially those with a focus on electronics, are aware that pre-compliance testing is incredibly important. As a result, it is vital to figure out which anechoic testing chamber offers you the best results. While they are quite a few options to choose from, you will need to determine which one is right for you, depending on your application requirements as well as your budget. This article will make it a little easier to determine what the best option for you is:
The Semi-Anechoic Chamber (SAC)
There is no denying that the semi-anechoic chamber continues to be one of the more popular EMC chambers. The reason that it is referred to as ‘semi’ anechoic is that the equipment is capable of only partially absorbing the electromagnetic radiation. The reason that this option is commonly utilized is that it scores high in the correlation and repeatable elements. Thus, this increases the accuracy of the readings.
Now, in case you are wondering about the Fully-Anechoic Rooms, these tend to be underutilized. This is because experts have found it very difficult to get repeatable and correlated readings. Not to mention, there hasn’t been too much research done in this department either. So, for the time being, the semi-anechoic room offers a superior performance.
The Open Area Test Site (OATS)
Some companies that choose to do in-house testing have been known to rely on the open area test site. This equipment can also be found with third-party laboratories as well. This is not surprising considering that the main advantage with OATS is its accuracy. The lack of walls in the measurement area means that there is less chance of the energy getting through an absorber and getting reflected back. At the same time, it is precisely this design that also causes the most number of issues for OATS. The absence of a shielded chamber often entails that cell phone bands, FM radio band, and even air traffic are picked up. As this makes it difficult to notice the emissions, OATS testing tends to take a lot longer which is why more companies prefer SAC.
In case you are looking for a more budgeted option, then you may need to rely on a GTEM cell. They are heralded for the fact that they are not just cheaper than SAC, they are also a lot more compact as well. These cells can be used for radiated emissions and radiated immunity testing for certain products. While GTEM cells are undeniably useful, they do have some shortcomings. To start with, there is often a limit on the size of the products that you can test with these cells. They come in sizes between 30cm and 20 feet, so you will need to select the one that corresponds most closely with your product. Now, the other issue is that there is some measurement error with frequencies under 200 MHz. This can be rectified a little with the help of a current clamp that can measure the common mode current.
These are the most important and common testing chambers that you need to know about. Now, you can make a decision based on what is right for your company and product.