SF1145B

Due to market price fluctuations, if you need to purchase or consult the price. You can contact us or emial to us:   sales@allicdata.com

SAW filters are commonly used in many areas due to its low signal attenuation and good selectivity. High-frequency electronic communication device such as radio astronomy, direct sequence spread spectrum communication systems, satellite communication and terrestrial microwave communication systems all require SAW filter to suppress interfering background noise. SF1145B is a type of SAW filter specially designed for communication applications in the frequency range of 8-1587MHz.

SF1145B is a kind of SAW duplexer, which is a combination of a lowpass and highpass filter on a single substrate. Its main role is to separate transmitting and receiving signals in order to reduce mutual interference. In addition to the common characteristic of SAW Filter, SF1145B is featured with low insertion loss, high isolation, and great anti-interference performance. Application of SF1145B includes FM signal modulation, wireless telephone systems and signal reception sections of satellite systems.

SF1145B adopts the combline resonator working principle. It consists of two main parts, the combline resonator array and the acceleration-stabilized interelectrode acoustic filter. The combline resonator is formed by a set of interleaved metal lines on a piezoelectric substrate which will convert electric signal to surface acoustic wave(SAW). These waves will travel between electrodes that form the resonator and get reflected due to the specific equivalent element at the end. By controlling the distance between these electrodes and controlling the time of travel of the SAW, the filter can obtain the desired frequency characteristics.

The acceleration-stabilized interelectrode acoustic filter is composed of an input arm, an interdigital transducer(IDT), which is connected to a reflective section of the substrate and modulated with voltage to guide the SAW to the output side, and an output arm, which captures the output SAW. The IDT is coupled to two parallel-plate electrodes on the piezoelectric substrate, and the distance between the two electrodes is usually controlled with lead zirconate titanate(PZT) layer.

The reflective section of the substrate is patterned with two array entities, each of which consists of the electrodes of different lengths facing towards each other, producing a sequence of comb-like signals. These comb-like signals generate an output amplitude response that is the desired characteristic of the filter. The input signals will be amplified and added to the reflection of the electrodes, and the response signal will be produced at the output side.

In summary, SF1145B is an application-specific SAW filter, which can be used in many communication systems because of its application field, and its overall characteristics of low insertion loss, high isolation and great anti-interference performance. It adopts the combline resonator working principle, consisting of two main parts- the combline resonator array and acceleration-stabilized interelectrode acoustic filter- to achieve the desired frequency characteristics.

The specific data is subject to PDF, and the above content is for reference