Novel Microwave/millimeterwave Substrate Integrated Waveguide Filter

With the rapid development of communication technology,filters have been made the new requirements of being compact,multi-band as well as being easily integrated on planar circuits microwave/millimeter-wave system.In this paper,the novel resonant cavity structure of the substrate integrate waveguide filter(SIWF),the manufacture methods and the design method of the new material are investigated.The main research work of this paper mainly includes the following aspects: 1.Research on the SIWF miniaturization technology.This paper presents a miniaturization method of dual mode SIWF with the surface of double-Z cross slot lines structure.Compared with the conventional square-shaped dual-mode SIWF,the SIWF with cross slot lines structure can reduce the effective area of substrate integrated waveguide filter by 25%.In addition to the two controllable transmission zeros of the filter stop-band,a transmission zero is added to perform better stop-band characteristics.The experiment results show that the upper stop-band of SIW filter with double-Z cross slot lines has good out-of-band rejection performance.2.Research on dual band SIW Filter.A dual passband filter with etching cross slot lines and square loop slot line structure is proposed.The center frequency of the two pass bands can be controlled by changing the size of the square loop slot line.The center resonant frequency of the first passband can be determined and the offset of the center resonant frequency of the second passband can be adjusted by the structural dimensions of the cross-shaped slot lines.The frequency response of the required filter can be obtained by changing the parameters of the cross slot lines and square loop slot lines in the design of dual band SIW filter.3.Research on etching method of deep through hole for high resistivity silicon(HRS)wafers.The process parameters of Potassium hydroxide(KOH)solution for etching HRS are optimized,including concentration of KOH solution,bath temperature,ultrasonic power and concentration of IPA.Experiment results show that low surface roughness and high etching rate can be obtained by the optimized etching process,which is composed of fast etching stage and surface polishing stage.Deep through holes morphologies of Infrared laser etching and picosecond ultraviolet laser etching are characterized by Scanning Electron Microscopy(SEM).The physical mechanism of HRS etching with Infrared Laser and Ultraviolet Laser is analyzed.Experiment results show that the thermal diffusion control is the key to achieving good morphology of deep through-holes.The Bosch ICP processing method of HRS is studied and a three-stage process is proposed to realize the HRS deep through-hole.Micro-Raman spectroscopy is used to characterize the sidewall quality of the HRS deep through-holes.The morphology of HRS through-hole in different etching processes are compared and the influence of processing mechanism on the shape of via-holes is analyzed.4.Research on design and fabrication of SIWF based on HRS.The Ku-band Chebyshev filter is synthesized using low-pass prototyping and microwave structure simulation.The design method of cascade resonator filter is discussed.The influence of through-hole tilt angle on filter performance parameters is analyzed.The filter structure size is optimized and the high resistance silicon SIWF is fabricated.The results of SEM and AFM show that the quality of the metal layer on the surface of the silicon wafer and the inner wall of the through hole is good and the insertion loss of the filter is 1.2 dB,indicating that the use of high resistivity silicon is suitable for preparing the low-loss microwave SIWF.5.A novel millimeter wave quasi-circular waveguide cavity is proposed.The relationship between the size of the quasi-circular waveguide and the characteristics of the electromagnetic resonance is analyzed by finite element method.A novel dual-mode quasi-circular waveguide resonator with adjustable center frequency and zero point is proposed.The coupling structure and resonant frequency of the filter can be optimized respectively,and a dual-mode quasi-circular waveguide 3D filter operating at 160 GHz is designed.The millimeter-wave dual-mode quasi-circular waveguide resonator filter is fabricated by LTCC process and measured.The insertion loss of the filter is about 2.4 dB,and the in-band reflection coefficient is better than-17 d B.Unlike conventional through-hole magnetic coupling,the coupling between resonators is electrically coupled,favoring the design of narrow-band filters.6.A novel millimeter-wave quasi-coaxial resonator is proposed.The relationship between the characteristic structure size and the resonant frequency of the quasi-coaxial resonant cavity is analyzed by simulation.By coupling the quasi-coaxial cavity and the substrate integrated waveguide cavity,3-D millimeter wave quasi-coaxial filter is designed.The millimeter-wave quasi-coaxial resonator filter is fabricated by LTCC process and analyzed.The filter operating frequency is above 100 GHz,the insertion loss is 2.6 dB,and the reflection loss is less than 10 dB.