Design And Implementation Of Dual-band Ring Impedance Transformer Based On Complex Load

As an important component to solve the match between microwave transmission line and load,the impedance transformer plays an important role in the study of RF devices.The development of impedance transformer can also objectively promote the research and development of filter and power distributor,its importance in microwave engineering technology is self-evident.In recent years,with the rapid development of wireless communication and radar(such as global mobile communication system),some new requirements have been put forward for the multi-band,high-performance,miniaturization and high efficiency of the impedance transformer,and the traditional four-molecule one-wavelength transformer can not meet the increasingly complex practical needs.Moreover,because many RF components(such as RF chips and power amplifiers)are likely to be complex impedances in the transmission of input and output impedance,the matching study for complex loads is of some significance.In order to realize the performance of complex load transformation and dual band,but also to make the circuit size relatively small,a two-band design method of ring impedance transformer based on complex load is proposed.The specific research content is as follows:First of all,this paper starts with the transmission line impedance equation and the basic matching principle of the two-port network,analyzes the single-band matching conditions of the ring structure under real load,obtains the transmission line impedance expression,and clarifies the range of charge length value for the realization of the dual-band circuit.The result will be visually reflected in the two-dimensional plan in a linear lying plan,resulting in the achievable range of the center frequency ratio of the two operating bands.Secondly,the analysis method of the real load dual frequency band is extended to the complex load.According to the different loads under the first frequency point to the six case classification,the power length range and frequency ratio of each case are calculated,and the load relationship equation under the two frequency points is obtained by impedance constant.The 2D plan mapping is accompanied by the addition of the frequency ratio as a vertical axis,the three-dimensional coordinate system is built,and the new 3D mapping mode can visually show the designable range of the frequency ratio and electrical length.Finally,a replacement method is proposed for the testing of complex load circuits.The complex load of the original circuit is replaced with two transmission lines and an equivalent structure of a resistance cascade,and the replacement equation is calculated,which can solve the test problem of the complex load dual-band circuit by using this equivalent structure.Through the plate and simulation of the two sets of selected data,the current simulation results,electromagnetic field simulation results,the actual circuit board and the actual circuit measurement results are obtained in turn.The results show that the matching effect is good at the expected frequency point,the error is small,and the calculation result is in line with the expected calculation,which proves the practicality and accuracy of the dual-band design method.The study of this paper clarifies the design conditions of the impedance transformer of the complex load dual frequency band of the ring structure,provides a feasible solution for the realization of the dual-band impedance transformer based on the complex load ring structure and the actual measurement of the complex load,and also provides an analytical idea for the impedance transformation design of the complex load under the multi-frequency band.And through the mapping of two-dimensional plan and the mapping of the added frequency ratio of three-dimensional plot,the limit between the designable range of electrical length and frequency ratio is clearly defined.However,it should be noted that due to load replacement,the structure and performance of the circuit have been changed to a certain extent,so that the frequency band obtained in this paper is narrower,and the complex load under the two frequency bands has a certain correlation,I hope to be able to solve in the future study.