{"title":"An unbalanced/balanced MCF for cellular phone","authors":"T. Sakurai, Akihiro Soeda, T. Saitoh, O. Ishii","doi":"10.1109/FREQ.2001.956342","DOIUrl":null,"url":null,"abstract":"In a monolithic crystal filter (MCF) which has an unbalanced-input and a balanced-output, the attenuation on the lower side has poor repeatability caused by the variation of capacitance between each electrode. We examined an unbalanced/balanced MCF that has good and repeatable attenuation characteristics. We obtained more than 90 dB at fo-900 kHz for a 2-pole MCF (center frequency is 109.65 MHz, 3rd overtone, terminating impedance is 800 ohm//-0.3 pF). We also examined an unbalanced/balanced 3-pole MCF which has good characteristics. This is because the capacitance between each electrode is close to zero due to the shield effect of the center electrodes.","PeriodicalId":369101,"journal":{"name":"Proceedings of the 2001 IEEE International Frequncy Control Symposium and PDA Exhibition (Cat. No.01CH37218)","volume":"94 1","pages":"0"},"PeriodicalIF":0.0000,"publicationDate":"2001-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Proceedings of the 2001 IEEE International Frequncy Control Symposium and PDA Exhibition (Cat. No.01CH37218)","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1109/FREQ.2001.956342","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
In a monolithic crystal filter (MCF) which has an unbalanced-input and a balanced-output, the attenuation on the lower side has poor repeatability caused by the variation of capacitance between each electrode. We examined an unbalanced/balanced MCF that has good and repeatable attenuation characteristics. We obtained more than 90 dB at fo-900 kHz for a 2-pole MCF (center frequency is 109.65 MHz, 3rd overtone, terminating impedance is 800 ohm//-0.3 pF). We also examined an unbalanced/balanced 3-pole MCF which has good characteristics. This is because the capacitance between each electrode is close to zero due to the shield effect of the center electrodes.