Research And Design Of Microwave Power Equalizer

In wireless communication systems,equalizers are often used to correct the amplitude and frequency characteristics of transmission channels.In radar systems,it is usually located at the transmitter or receiver,which can greatly improve signal distortion.Some passive devices in microwave devices,such as filters,couplers,isolators,power dividers,etc.,have relatively complete comprehensive theoretical research and calculation methods.However,equalizers are special devices for different products and different working environments.It is difficult to design them with general theory and calculation methods.Few equalizers can meet the requirements of various working environments.Therefore,considering the above problems,we need to establish an optimized physical structure to achieve and make up for theoretical deficiencies.The adjustability of equalizer is also the direction that needs to be explored continuously.Generally speaking,for an equalizer,its amplitude adjustment range needs to be wide in order to ensure better flatness of the output signal,and its voltage standing wave ratio needs to be small to reduce the interference to the system,and its size needs to be small in some special circumstances.In this paper,three different types of power Equalizers Based on coaxial cavity,folded substrate integrated waveguide and microstrip line are studied and designed,which have the characteristics of volume,bandwidth and standing wave ratio.The adjustability and other aspects are better than the same type of equalizer.The main work of this paper is as follows:1.An adjustable equalizer based on coaxial resonator TE011 mode working at 5-6GHz is designed.The straight line of the designed equalizer is a 50Ω microstrip line,and 17 cavities can be inserted into fine-tuning screws,fine-tuning screws,and ferrite absorbing rods.The volume of each cavity can also be adjusted by a coarse adjustment nut.The equalizer can meet the accuracy requirements of 50 sampling points in the working frequency band.The cavity is also designed with PTFE material to fix the fine-tuning screw,so that it can maintain good performance in bumpy environments,and the equalization amount can reach up to 25 d B.Pre-equalization is performed by etching spur lines on the microstrip line,so that the volume is further reduced by 23.6% under the condition that the working index is met.2.Two ultra-wideband microstrip equalizers are designed,one of which is a positive slope equalizer,its working frequency band is 6-18 GHz,the equalization amount is controlled at12 d B-1d B,and the return loss is less than-15 d B.It consists of four multi-branch structures.The end of the branch structure is loaded with thin-film resistors to control the amount of absorption.Changing the direct length and width can change its resonant frequency and loss,and its equalization error is less than 1.5d B;the other equalizer is an ultra-wideband operating at0.7-20 GHz,the initial automatic design of the microstrip resonance branch is carried out based on the Monte Carlo least square method,and then optimized by the full-wave electromagnetic simulation software,and the equalizer that meets the technical indicators can be quickly obtained.3.The tunability of the equalizer based on folded substrate integrated waveguide is investigated.The folded layer is made into a drawable sheet,and the electromagnetic wave of the microstrip line is coupled to the upper layer of the substrate integrated waveguide by means of hole coupling.Adjust the resonant frequency and the amount of equalization.The finally realized tunable equalizer based on folded-substrate integrated waveguide can reach up to 12 d B in the working bandwidth of29-34 GHz.