The Research Based On 3.1-10.6GHz Ultra-Wideband Image Reject Mixer

In the UWB wireless communication receiver system, the mixer is one of the important components in the system. The degree of image rejection, conversion loss, isolation and noise directly affect the performance of wideband receiver system, so the research of the UWB balanced image rejection mixer is important. In this thesis, combined with a variety of UWB planar devices, miniaturized planar ultra-wideband balanced image rejection mixer is produced to meet the UWB wireless communication requirements.Firstly, the theoretical analysis of the program block diagram of Ultra-Wideband UWB balanced image reject mixer is to ensure the feasibility of the program. Under the program, the ultra-wideband double-balanced mixer was designed to meet the optimum degree of image rejection. To lower conversion loss of mixer, a wide stopband of low-pass filter was designed for a good harmonic rejection. The ultra-wideband power splitter was designed so that the LO signal can be equally assigned to the two input ports of of the balanced mixers. The ultra-wideband directional coupler was fabricated so that the RF singal can be in phase quadrature. The broadband lumped directional coupler was made to meet the requirements of broadband image rejection. HFSS and ADS was used for the circuit simulation of each part the circuits, while processing tests were to verify the accuracy of the theoretical analysis and simulation. After that, the overall processing circuit simulation and tests was to meet the design requirements. To prevent the internal electromagnetic interference among the devices, the layout of the circuit was improved for good performance.The research work of 3.1-10.6GHz ultra-wideband balanced image rejection mixer was firstly completed in this thesis. A diode double balanced mixe based on ultra-wideband microstrip to coupled slotline transition balun was proposed firstly in this thesis, where the conversion loss was less than 14 d B and the isolation among the ports is greater than 20 d B. The thesis has been hired by the Microwave Journal(SCI). Every component of the circuit of the programs was fabricated and measured to meet the requirements. Processing test in the whole circuit of the first edition among the 3-11 GHz band showed that onversion loss is less than 15 d B, LO-RF isolation is greater than 15 d B, LO-IF isolation is greater than 20 d B, image rejection is greater than 15 d B, the return loss of RF and IF ports are larger than 13 d B and 20 d B. So it basically meets the design requirements. The measured data of improved circuitry is superior to the design requirement and the research topics were successfully completed.