Study on Stacked-lc Bandpass Filters Constructed on Multilayer Substrates
|School||Nanjing University of Posts and Telecommunications|
|Course||Electromagnetic Field and Microwave Technology|
|Keywords||Band-pass filter Multilayer dielectric structure Layered structure Cascade|
Modern wireless communication system of the RF , microwave filter requirements in miniaturization , integration is getting higher and higher , multilayer dielectric structure conducive to the realization of highly integrated RF and microwave circuit research has been widespread concern . This paper studies how to take advantage of the layered structure to further improve the integration of the LC filter based on multilayer dielectric structure . The main innovation of the thesis work : (1) A method of using a laminated structure of the second order LC band-pass filter model through the inductor is set on capacitor vertically above , so that the structure of the filter to become more compact, at the same time due to metal spacer plate between the capacitance-inductance , capacitance between the inductor unnecessary coupling is relatively reduced , reducing the complexity of the filter design . (2 ) on the basis of the above second-order filter designed a four- order coupled band-pass resonant filter add a feedback path , and an additional layer of feedback capacitance (ie filters ) effectively improved filter the stopband rejection characteristics , so that the filter in the center frequency of the second harmonic , third harmonic at and near the fourth harmonic frequency each a transmission zeros , greatly improve the performance of the filter . The multi-layer dielectric structure with a more in-depth study and application in the field of filter design , but between the multilayer dielectric structure capacitance inductance parasitics and coupling effect will reduce the performance of the filter , the filter structure is often difficult to do very compact . In this paper, the design of the vertical structure of second-order LC filter to ensure good performance on the basis of full use of the advantages of the multi-layer structure , increase the integration of the filter . On this basis , a cascade of second-order filter stopband rejection than 50dB high performance four order filter .