B39380K9352M100

Surface Acoustic Wave (SAW) filters are widely used for many applications in both consumer and commercial domains. Consisting of an array of metal electrodes deposited on top of a piezo-electric substrate, SAW filters provide an efficient way of isolating narrowband signals from wideband noise. B39380K9352M100 is a SAW filter designed to provide high out-of-band suppression and low passband insertion loss in the RF communication field. This paper discusses the application field and working principle of B39380K9352M100.

B39380K9352M100 is a SAW filter designed for radio receivers and transmitters operating in the 500-1000 MHz frequency range. It provides a very sharp low pass response with a steep roll-off that enables tight adjacent channel rejection in the order of 90dB below the passband. This makes it suitable for applications in the cellular communication broadband networks, such as GSM/UMTS/LTE with adjacent channel leakage ratios (ACLR) of 75 dB or higher.

The construction of B39380K9352M100 starts with a special piezoelectric substrate material, such as lithium tantalate (LiTaO₃) or lithium niobate (LiNbO₃). Electrodes are deposited on the substrate in a periodic pattern defined by the desired filter transfer function. When a voltage is applied to the electrodes, acoustic waves are generated that propagate along the surface of the substrate. The input signal is fed into one of the electrodes, causing the acoustic waves to reflect off the other electrodes, creating a bandpass response. The out-of-band signal components are blocked because the acoustic waves will be attenuated as they propagate along the filter.

B39380K9352M100 achieves its superior out-of-band suppression performance with the help of two highly efficient transducer arrangements. The first one uses quadraphonic transducers, which are made up of four individual transducers interleaved between the two layers of electrodes. Each transducer is fed from adjacent electrodes with a voltage of opposite sign. This generates acoustic waves of varying phase that can cancel each other out, reducing the amplitude of the out-of-band components. The second transducer arrangement uses a coplanar waveguide with a group of nine interleaved transducers, which are fed with alternating voltages to produce a crossed-over field that presents an additional barrier to the out-of-band signals.

B39380K9352M100 is a versatile SAW filter with a wide range of applications in the RF communication field. Its low passband insertion loss combined with its very high adjacent channel rejection makes it suitable for use in cellular and other high-bandwidth systems. The use of advanced transducer arrangements ensures that it provides superior performance for low out-of-band noise in these and other applications.