烟支湿度与密度检测的微波谐振腔传感器研究.PDF

维普资讯 第 20卷 第5期 传 感 技 术 学 报 Vo1．20 No．5 2007年 5月 CHINESE JOURNAL OF SENSORSAND AC兀IAr0RS May．2007 A stmyOilMicrowaveResomneeCa,itySemro forDeteef~ Og~ tte~ dityandDemity L 【，Zhi—yuan ，SUN Wen—quan，rL，Zhi—gang，SHIPin—pin，DINGHua，ZHOUJia—she (SchoolofElectronicEngineering，XidianUniversity，X ”710071，China) Abstract：Thebasaltheoryandbasicprincipleofmicrowaveresonancecavitydetectionaredissertatedwith tiny-disturbancemethod．Relativevarietiesproducedbyelectromagneticparameterofdielectricmaterials affectedbymicrowave，including permittivityandwastage，arealso analyzed anddiscussed．Then the mathexpressionisestablishedbetweencigarettehumidityanddensityandfrequencyoffsetandhalfpower pointbandwidthofresonancecurveofresonancecavity．Henceatypeofmicrowaveresonancecavitysensor calledrepeating-entrymodelisdesignedandmade．TheTMOIOresonancemodelisusedtothereal—time detectionofcigarettehumidityanddensity．From amplitude-frequencypeculiaritydetectedunderthecon— ditionofvacuum resonanceandcigaretteinexistencewiththeswepttechnique，resonancefrequencyf， peakpowerP andhalfpowerpointbandwidth(ucouldbeobtained，addingtosomerelativemathematical formulas，cigarettehumidityanddensitycanbecalculatedrespectively．Thedetectiontechniquehasmany advantagessuchasspeedinesscontinuation highresolutionratenon—pollution safeandconvenientopera— tion，etc．Anditisapplicabletoindustrialsurveyonthespot． Keywords：microwaveresonancecavity sensor；cigarettehumidityanddensity；tiny—disturbancemethod； TM 010model；theswepttechnique EEAoC：7230 烟支湿度与密度检测的微波谐振腔传感器研究* 卢智远 ，孙文权，吴志刚，石频频，丁 华，周佳社 (西安电子科技大学电子工程学院，西安 710071) 摘 要：对微波谐振腔微扰法检测基本理论和工作原理进行了论述，对微波作用的介电材料的电磁参数 “介电常数”和 “介电 损耗’产生的相对变化进行了分析讨论，建立了烟支密度和湿度与谐振腔谐振曲线的频偏及半功率点带宽的数学表达式，设 计制作了重入式微波谐