Research And Design Of Microwave/Millimeter-Wave Substrate Integrated Waveguide Equalizers

Equalizers play an indispensable role in RF,microwave and millimeter-wave circuits and systems,especially in broadband application.For most active and passive circuits or components,with the increases of frequency,a decrease trend in gain,an increase trend in insertion loss or a gain(insertion loss)fluctuation in the passband exist objectively.This kind of characteristic,caused by the distortion of electromagnetic signal,takes inevitably rooted in the circuit itself,which has an adverse impact on the dynamic range and performance of the system.In order to ensure the quality of signal transmission,the amplitude equalizer is usually used to correct the signal amplitude,to obtain a flat signal in the required frequency band.With the development of advanced electronic systems,low cost,low loss,miniaturization and high integration have gradually become the mainstream trend of circuit system design.Substrate-integrated waveguide(SIW),representing an emerging and promising circuit structure,is suitable for the design of microwave and millimeterwave circuit and system.It has the advantages of low radiation,low insertion loss,high Q-value,high power capacity,small volume,lightweight,miniaturization and easy to integrate.At the present time,SIW has been widely used in the development of microwave devices such as power divider,antenna,and filter,due to its excellent structural characteristics.However,from the relevant reports,the equalizers implemented on SIW technology are still rare.Based on the attenuation characteristics of SIW surface resistance,three novel SIW equalizers are studied and designed in this thesis:Firstly,one novel design method and idea of SIW equalizer based on absorbing material are proposed,and the theoretical derivation of this kind of SIW equalizer is given.In addition,for the SIW equalizer,the TRL calibration standards applied to Ka-band is designed and fabricated.The SIW equalizer has the advantages of lower cost,larger range of equalizing value(3-25 d B),easier fabrication(achieved on traditional PCB),and lower insertion loss at the maximum frequency point(2.3 d B@40 GHz).Then,another novel design method of step SIW equalizer based on microwave resistors is proposed,and the TRL calibration standards applied to Ku-band is designed and fabricated.The equalizing values of SIW equalizer are approximately proportional to the number of microwave resistors introduced,which can be considered as a step equalization characteristic.The SIW equalizer is implemented on the traditional PCB(Rogers 5880),which is a planar structure with low cost and easier to realized in process.It can be used in microwave circuit and antenna feed network for broadband amplitude balance and compensation.Finally,the third novel design method of millimeter wave SIW equalizer with low insertion loss and large equalizing value,which can be applied to broadband feed network,is proposed.The TRL calibration standards,applied to ceramic substrate in Ka-band and suitable for GSG coplanar probe,is designed and fabricated.The SIW equalizer has large range of equalizing value(3-20 d B)and low insertion loss(0.94 d B@40 GHz).