BAW vs. SAW RF Filters

Why Are RF Filters Needed?

Radio frequency (RF) filters are cornerstone components in all RF/microwave systems, especially wireless communication systems with many channels or bands. The primary function of an RF filter is to attenuate signals in certain undesired frequency bands while only minimally impacting signals in desired frequency bands.

RF filters are crucial, as there are many instances where undesirable signals (known as interference) can result in degradation or even damage to system functionality. In wireless communication systems, various RF filters are used at the input of receivers to attenuate signals outside the band of interest. RF filters are also used to reduce harmonics, spurious content, and out-of-band leakage from transmitter circuits. In many cases with modern electronics such as smartphones, these devices are equipped with several wireless communication technologies that could interfere with each other if not properly isolated using RF filters—a design challenge known as coexistence (Figure 1).