SAW Filter Design Basics and Manufacturers

SAW filter design requires understanding principles like frequency response and material properties. This guide covers design essentials and highlights top manufacturers. The name SAW is the short form of Surface Acoustic Wave. This wave is composed of coupled compressional & shear wave type in which energy is confined near the surface.

The SAW has two benefits:

• It allows electro-acoustic coupling via the transducer.
• Its velocity is 10⁵ times less than EM wave (Electromagnetic wave). This is the major difference between SAW and EM waves.

Due to this, SAW is used where EM wave-based designs are impractical to be developed.

Following table mentions comparison between SAW and EM dimensions vs frequency/delay.

Due to high operating frequencies and linear delay they are used for broad range of signal processing applications. The applications include both commercial as well as military systems.

SAW based components are used in radars, Cable TV, VCR, navigational and cellular applications. Moreover IF filters, signal analyzers, synthesizers, clocks and tags will use SAW concept based designs. The properties of SAW such as reflection, transduction, non-linearities and re-generation make them popular.

SAW devices are manufactured using anisotropic materials which include LiNbO3 (lithium niobate), LiTa2O5 (lithium tantalate) and quartz. Among SAW devices, SAW filter is widely used for many applications such as medical, telecommunications etc.

Following are the specifications of SAW filter.

• Filter Bandwidth of operation ($B_1$)
• Transition Bandwidth ($B_2$)
• In-Band Ripple ($R_2$)
• Out-of-Band Sidelobes level ($R_1$)
• Group delay variation over passband as shown
• Insertion loss
• Size and package type

SAW Filter Types

RF SAW Filter Manufacturers

Following is the list of popular RF SAW filter manufacturers:

• Oscilent Corporation
• Vectron
• Murata
• Maxim Integrated
• Dove Electronic Components, Inc.
• Amplitronix
• Filtronetics, Inc.

Conclusion

Mastering SAW filter design is essential for RF engineers. Choosing the right manufacturer ensures access to high quality components for reliable systems.