FDD/TDD Reconfigable If Subsystem Design For The Ka Band Communication Link Machine

Nowdays informatin technology is dominating our society.The development of communication technology provides the technical foundation for the information society. With the rapid development of communication technology,microwave frequency spectrum resources become increasingly tense. The millimeter wave band spectrum has abundant resources.Millimeter wave communication systems with wide transimission band,large capacity of data characteristics become the focus of all countries.This thesis talks about millimeter communicaiton front-end system works in Ka band,designs the reconfigable IF subsystem.Under the control of the IF control module,we can compl ete the FDD mode and TDD mode switching or working at the same time,the switch of each signal link,the signal gain control,the switch of different channel bandwidth and the link power detection.Several types of basic structures of the communication transceiver structure is firstly introduced in this thesis,the selection of the superheterodyne structure with two level inverter is based on the features of the system.According to the index and function of the intermediate frequency subsystem,we design the analog RF link and digital control circuit architecture. Then we finish the design of the concrete function module circuits,the selection of the chips,the design of schematic circuit,the design of the PCB circuit board and cavity,the performence vertification. We show the testing results of each transceiver link.We finally show the whole RF front-end module testing results,verify the IF subsystem to ensure the normal work of the whole RF front-end module and achieve the system specificaion.The tunable filter is an important part of the reconfigurable system.We usually use filter swithcing scheme to deal with engineering problems.In this thesis,we did some exploration work about the microstrip bandwidth tunable filter.We design two microstrip tunable filter in the intermediate frequency 140 MHz and 1.25 GHz respectively.The microstrip tunable fiter based on variable capacitance diode has the characteristics of high tuning speed,low insertion loss and low cost.We design the bandwidth tunable filter through the even odd mode analysis of the resonator structure and the theoretical derivation of the zero point and pole point of the resonator.The design of the bandwidth tunable microstrip fliter has certain innovation and provides the technical foundation for the improvement and innovation of the system in the future.