Research On Snake DGS Microstrip Line Frequency Characteristic Analysis And Application

Defect Ground Structure(DGS) is etching a periodic or aperiodic shape on the metal earth plate of the microstrip line then forming a new type of structure. The circuit substrate material of the effective dielectric constant varies with the change of the shape of the metallic ground plane etching change, which means the distributed capacitance and distributed inductance are changed on the microstrip line. So the microstrip line with DGS shows the characteristic of low-pass band-stop characteristics, the high characteristic impedance, slow-wave. In the microwave millimeter wave circuit, widely used DGS is to improve the performance of the circuit, gradually becomes a research hotspot in the field of microwave circuit design.The thesis takes the systematic induction and reorganization of the DGS development and research status. Through analyzing and deducing the frequency characteristic and LC equivalent circuit mode of the classic dumbbell and spiral DGS, it proposes the snake DGS that change the rectangular aperture into the serpentine aperture. For the frequency characteristics of the snake DGS which is lateral deformation, the subject establishes the new LC equivalent circuit model and deriving the parameters, and uses the control variable method analyzes the influence of the snake DGS frequency characteristic and the equivalent LC circuit parameters when the parameters has changed. Then improves the existing design method of DGS microstrip filter in the literature, and applies the lateral deformation of snake type DGS and its equivalent circuit to the design of low pass filter. Respectively takes the electromagnetic simulation and circuit simulation of the designed filter and equivalent circuit in HFSS and MATLAB environment. Contrasting and analysising the simulation results shows that circuit simulation curve and the electromagnetic simulation curve have good consistency. The result shows that the structure can obtaine the lower frequency attenuation and more resonant frequency point in the case of not increase the defect area, and reduces the number of DGS in the condition of the selected filter under the same order. Based on superiority of DGS, the DGS finally loads into the dual-frequency microstrip patch antenna, to improve the mutual interference between the receive and dispatch signals and the disadvantage of easy to excite the high order harmonic. The simulation and test results shows that dual-frequency microstrip patch antenna based on DGS not only successfully suppress the high order harmonic, but also obviously improves the isolation of the port, it has reached the design requirements. The research of analysis and application based on snake DGS microstrip line frequency aharacteristic provides theoretical basis and design reference for researching and designing the DGS microwave integrated circuits with the high performance, small size, low power consumption.