一、Characteristics

      The main role of the surface acoustic wave filter (also known as SAW filter) is to filter out noise, in order to filter unnecessary signals and noise to improve the quality of reception as the goal, to achieve the filtering of specific signals. The principle of the surface acoustic wave filter is to use the piezoelectric characteristics of piezoelectric materials, with the input and output Transducer (Transducer) to convert the electrical signal of the radio wave input into mechanical energy, after processing, and then convert the mechanical energy into electrical signals to achieve the purpose of separating currents of different frequencies. These products can replace LC resonant circuits for interstage coupling and filtering. The disadvantages of the surface acoustic wave filter are that the insertion loss is larger than that of the LC resonant circuit, the bandwidth is relatively narrow, and the download speed is slow. However, it is easier to install than traditional LC filters.

      Surface acoustic wave filter parameters (frequency range: 30MHz--3GHz; Bandwidth: 100KHz--200MHz), small insertion loss (≤2.0dB), patch package (SMD1814, 2016, 3225, 3030, 3070, 3838; 5050; 7050; 1365, D11, F11, TO39), the operating temperature is wide (-25℃--+60℃; Storage temperature: -45℃--+85℃). The product has good consistency, more convenient installation, smaller size, cheap price, high device integration, stable and reliable performance in the full temperature range, and meets the requirements of military working environment (-55℃ ~ +85℃). It has the function of suppressing high order harmonics, image information, transmission leakage signal and all kinds of parasitic clutter interference, and can also realize the filtering of amplitude-frequency and phase-frequency characteristics with any required accuracy.

saw filter schematic

二、Model & electrical characteristics

三、Application & attention

       The surface acoustic wave filter (SAWF or SAW, for short) has a simpler installation and smaller volume, so the surface acoustic resonator is widely used in various wireless communication systems, television sets, wireless transmitters and other RF circuits. When in use, the input/output outlet can be used interchangeably, but it should be noted that the grounding end is well grounded, otherwise it will affect out-of-band suppression and flatness indicators. The welding temperature should not be too high and the welding time should not be too long. If reflow welding is used, the recommended temperature is recommended, and wave soldering is not recommended. Products should be stored in the ambient temperature of -10℃~40℃, relative humidity is not more than 80%, the surrounding environment is not acidic, alkaline and other harmful gases in the warehouse. Do not soak when cleaning, it is recommended to wipe with alcohol.  

      The company has a variety of package types of surface acoustic wave filters for users to choose, flexible design, support customization (input/output form and shape size can be designed according to user requirements). Various frequencies of surface acoustic wave filters can be customized. Because the indicators of microwave components are related to each other and sound to each other, the user needs to clearly state the indicator requirements before customization. Once the product is made, it cannot be changed. If there are indicators that exceed the physical limit of the material itself, the best indicators can be achieved through negotiation between the two parties.