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With the continuous development of the communication industry , such as microwave communications, satellite communications systems and optical communication , mobile communication system dedicated phone , digital cordless phones and professional communication network system , have gained rapid development . The working frequency of these mobile communication systems have been reached or exceeded 1GHz . Increasingly important as key components in the communication system , the SAW filter , and its development trend is the high center frequency , low insertion loss, miniaturization , and low cost . This paper introduces the basic concepts of SAW , SAW filter works and design methods . SAW filter according to their works can be divided into horizontal filter and resonator filters , we highlight the transversal filter design methods , design and production of the IF SAW filter and digital Fourier transform method . To improve the performance of the SAW filter , from the following aspects : technical research on digital Fourier transform . Transversal filters , focusing on how to reduce the insertion loss . By increasing the receiving IDT weighted logarithmic and their transformation to reduce the insertion loss . You can also meet the requirements of the insertion loss through increased acoustic aperture . Can be expanded in the actual metal interdigital within one cycle of the duty cycle to achieve the reduction in the insertion loss . Then the research process . In order to meet production requirements , we have improved the production process . For example, the process of cleaning, coating, lithography , corrosion , to meet production requirements , improved process methods to improve the efficiency of the entire process , reduce costs , shorten cycle . Through the analysis of these issues , research , our design , the successful development of a military IF SAW filter , its performance fully meet the design requirements , and achieved satisfactory results , and provide information on manufacturers , have been sold in bulk , its performance indicators in full compliance with the requirements.
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