Research On The Design Of Microwave Passive Devices With Multi-bit Planar Fragment-type Structures

With the rapid development of modern wireless technology,the transmitters and receivers are required to have smaller size and better performance.Accordingly,new requirements are put forward for the structural design of planar microwave passive devices.The existing structural design methods of planar microwave passive devices mainly include parameter optimization method for conventional structure or its combination/deformation structure and distribution optimization method for simple fragment-type structure(i.e.1-bit FTS).The former is limited to finding a structure with the potential to achieve high performance,while the latter is limited to the contradiction between achieving high performance and optimization time.In order to meet high performance design using fine structure without significantly reducing the efficiency of optimization,this paper uses the multi-bit fragment-type configuration technology combined with multi-objective evolutionary algorithm based on decomposition to achieve high-efficient and high-performance microwave passive device design.The main research work of this paper includes:1.The design scheme of microwave passive devices based on multi-bit fragment-type configuration is proposed.By introducing fine structure into the cell of multi-bit FTS,the optimal design of high-performance microwave passive devices can be realized without fine and uniform grid division of the whole design space,which can effectively save time cost.The advantages of multi-bit fragment-type configuration technology are clarified from two aspects of design efficiency and electrical performance.In addition,the selection principle of planar multi-bit FTS cell and its form for different applications are given.2.Design of low-pass filter(LPF)based on multi-bit fragment-type configuration.Based on the scheme of combining preset bent direct-current transmission structure and loaded multi-bit FTS structure,a new design technology of high-performance miniaturized LPF is proposed by using the overall optimization strategy of FTS and regular structure parameters.When the design space,objective functions and decision space are the same,the LPFs are designed based on 1-bit and 2-bit fragment-type configuration technology respectively.The comparison results show that the 2-bit configuration technology can achieve higher performance and design efficiency.3.Design of multi-bit FTS bandpass filter(BPF)combined with vias.A coding scheme of 2-bit FTS combined with vias is proposed.For the regular and irregular design areas,the 2-bit fragment-type configuration design is carried out.Without any structure preset,the miniaturized and high shape factor 2-bit BPF design is realized.Compared with the BPF with 1-bit FTS and regular structure,the performance is significantly improved.4.Design of wideband power divider combined with multi-bit fragment-type configuration combined with lumped elements.For Wilkinson power divider,the theoretical constraint criterion of its isolation network is given for the first time.The bandwidth of power divider with different isolation networks can be easily determined according to the return loss and isolation index of power divider.Furthermore,a multi-bit FTS coding scheme combined with lumped elements is proposed to optimize the multi-bit isolated network,a wideband high-performance Wilkinson power divider is designed,and the performance of the designed isolation network is verified by the constraint criterion.5.Exploration of new fragment-type configuration technology.For some specific applications,in order to further reduce the optimization time and take into account the necessary fine structure,the 1+-bit discrete structure configuration technology is proposed,and its coding scheme is given to obtain a design matrix less than 2-bit configuration.The effectiveness of the new low-bit configuration technology is verified by designing a new directional coupler.In conclusion,the design of typical planar microwave passive devices is carried out around the multi-bit fragment-type configuration description method,which provide new and more effective design method for the design of high-performance and miniaturized microwave passive devices.