Research On Monolithic Integrated Switching Filter Bank Based On LTCC Technology

5G era is coming,the communication channel number will increase obviously,passive components such as filters in wireless communication system front-end occupy large area.Hardness to choose working frequency,to a great extent,will affect the quality of communication.Therefore,it is necessary to study a small,high reliability and simple frequency tunable filter to solve the above problems.Low Temperature co-firing Ceramic technology(Low Temperature Co-fired Ceramic,LTCC)as a new type of packaging technology,which is commonly used in passive components,such as capacitance,inductance,resistance and makes filter completely buried in the ceramic to realize 3D circuit in the form of buried layer interconnect and to realize the miniaturization of the passive components.The introduction of LTCC technology undoubtedly leads to a step in the design reliability and design dimension of the passive components such as filter,power splitter and duplexer.In this paper,a monolithic integrated switched filter bank based on LTCC technology is studied.Based on the research background of LTCC filter in the laboratory,this article firstly combines the LTCC band-pass filter with switched circuit in PCB process,designing a four-channeled switched filter bank,which can realize the every single selection of center frequency in 170 MHz,140 MHz,110 MHz,70 MHz,By using the network analyzer for actual testing,the entire switched filter bank perform well,but the extent of the circuit miniaturization still exhibits insufficient.In view of this problem,this paper designs a single-chip integrated eight-channeled switch filter bank based on LTCC process.All the switched circuit and filters are designed based on LTCC technology and the switched chips implemented by surface mounting.The design method satisfies the switch group filter miniaturization and the high reliability of monolithic integrated design requirements.The overall size of the eight-channeled monolithic integrated switch based on LTCC technology filter bank overall size is 74.0 mm * 24.0 mm * 2.6 mm.which can realize the selection of eight different frequency band-pass filters with high and low level power control.The measured performance of switched filter bank and and design calculation values keep in good consistency,meeting the design demand,providing the basis for radio frequency(RF)wireless communication system of monolithic integrated design.