Research On Wideband Gain Equalizer For Microwave Power Module

Equalizer is playing more and more important role in the microwave communication system, such as randar transceiver and microwave power modules. The development of wireless communication and radar systems increase the requirements for broadband applications, which leads to unprecedented challenges of the microwave amplifier designing; The various indicators of new type transmitter modules become more strict. High flatness, wide bandwith and low cost become basic requirements of transmitter modules. In the broadband condition, improving the flatness of the microwave system with a gain equalizer is a common and effective way. More and more people prefer to use wideband amplifier and gain equalizer together.In this paper, an investigation on the microwave wideband gain equalizer and comprehensive theory was made based on the project needs. By analysis the advantages and disadvantages of these theory, the gain equalizer suitable for the needs of the project is selected. Computer optimized designing is selected based on the analyzing of different methods. In a given circuit, the parameters of the compnents are obtained by optimizing, and the designed gain equalizer meets the need of project. In this paper, three types of microstrip gain equalizer with different notch filter and topological structure are designed. Their advantages and disadvantages are discussedFirst, the traditional equalizers are made by several notch filters which are constituted of resistors and resonators, and whose attenuation can be controlled. Resonators are generally formed by λ/2 or λ/4 short stub or open stub. The traditional equalizer has the disadvantage of larger size. And it is not easy to achieve complicated equalizer. In this paper, a smaller and more complicated equalizer is designed by using a new type of resonant structure-spurs line resonator, whose size can be smaller than λ/4 based on changing odd and even impedance to controlling resonance’s bandwidth.Second, conventional equalizers make use of λ/4 transmission lines matching network to reduce standing waves. But making use of the computer optimization to calculate initial value of impedance is not effectively. In this part, a low VSWR equalizer is designing by new topology of the network which is based on scattering matrix of microwave network.Finally, a millimeter wave equalizer at frequency of 86-100 GHz is designed to improve the gain flatness. The resistance can no longer useful to adjust the amount of attenuation in frequency band of 3mm. So we decide to design the equalizer by using coupled resonator which can adjust the amount of attenuation with coupling coefficient.In this paper, several different types of equalizer are designed based on different purposes. The final measured results demonstrated the feasibility of the several methods to achieve the equalizer.