Microwave Attenuators: Types and Applications

Microwave attenuators play a critical role in managing signal strength within communication systems. This article explores what a microwave attenuator is, its primary functions, various types, and their applications across industries.

Attenuators are widely employed in RF testing, signal control, and power management to achieve precise signal levels in communication and radar systems. Basically, attenuators are passive devices which control power levels in microwave systems by absorbing the signal. An attenuator that attenuates the RF signal in a waveguide system is referred to as a waveguide attenuator. There are two main types: fixed and variable. They are achieved by the insertion of resistive films.

Types of Microwave Attenuators

1. Fixed Attenuators: Provide a constant attenuation level. They are used in systems requiring stable signal control.
2. Variable Attenuators: Allow adjustment of attenuation levels. These are common in testing setups and dynamic environments.
3. Step Attenuators: Offer discrete steps of attenuation. They are used in systems requiring precise and repeatable control.
4. Programmable Attenuators: Controlled electronically or via software. These are suitable for automated and remote applications.
5. Coaxial Attenuators: Designed for coaxial cable systems. They ensure minimal reflection and high-frequency compatibility.

Figure-1: This figure depicts a coaxial line based fixed type of attenuator. Here resistive film is fixed at the center conductor which absorbs the power and as a result of power loss and hence the microwave signal gets attenuated. This is referred to as a coaxial line attenuator.

Figure-2: This figure depicts a waveguide based fixed type of attenuator. Here a thin dielectric strip with coated resistive film is placed at the center of the waveguide. The film is placed in the waveguide parallel to the maximum E-field. In a variable type of waveguide attenuator, a resistive vane is moved from one side of the wall to the center by using a screw where the E-field is considered to be maximum. This resistive film is shaped to give linear attenuation variation.

Waveguide Attenuator Manufacturers

The following are manufacturers of waveguide attenuators of various types. They cover low power, high power, fixed and variable types for a wide range of frequencies. They cover an attenuation range from 0 to 40 dB and more. These manufacturers also manufacture waveguide switches, waveguide adapters, and other useful waveguide components.

• Waveguide Solution Limited, UK.
• Flann Microwave Ltd.
• Advanced Technical Materials Inc.
• Millitech Inc.
• Elmika, Lithuania
• CERNEX, Inc.
• Keysight Technologies
• Vector Telecom
• Pivotone Communication Technologies,Inc.
• LUSO ELECTRONICS
• Microwave Communications Laboratories, Inc.
• Microlab, A Wireless Telecom Group Company.
• Wenteq Microwave Corporation
• Zysen Technology Co., Ltd.
• RF Com Limited
• Antenna Systems and Solutions

Conclusion

Microwave attenuators ensure precise signal control in high-frequency applications. Understanding their types helps in selecting the right one for specific requirements, making them invaluable in modern communication and radar systems.