RF Attenuator Basics & Selection
RF Attenuators are components that reduce the amplitude level of an incoming signal. They are used to protect systems from receiving a signal level that is too high to process. The unit used to everything RF enable you to search for RF attenuators from over 50 manufacturers – You can filter the results based on your requirements.
Types of Attenuators
Fixed Attenuators: These attenuators are usually connectorized or available in a surface mount package. They are passive attenuators that provide a fixed attenuation level. Most of these products are available in a series, which have a number of attenuation levels available.
Variable Attenuators: These attenuators provide an attenuation range i.e they can be regulated to provide a particular attenuation level. Typically, the attenuation level can be modified by changing the voltage applied to an input control line.
Step Attenuators: These are attenuators where the attenuation level can be modified in fixed steps.
When selecting an RF attenuator it is important to know the parameters that you need to specify. Below are a list of the key parameters to look out for when selecting an attenuator:
Attenuation: This is the level of attenuation that you require. If you are looking for a fixed attenuator, then this would be a signle attenuation level in dB. However if you are looking for a variable attenuator then this would be an attenuation range that you want to work with.
Attenuation Accuracy: This is the level by which the attenuation level can vary.
Frequency: This is the frequency range over which the attenuator can operate while maintaining its electrical characteristic i.e Attenuation level, VSWR etc. The attenuation level usually varies over the frequency band of interest. It is important to see the attenuation response over the frequency band of a product.
Impedance: Attenuators are usually desiged to operate with a characteristic impedance of 50 Ohms, however 75 ohms attenuators are also quite common. It is important to match the characteristic impedance of the attenuator to that of the system/circuity where it will be used. This will minimize reflections.