Investigation Of Pattern Corrected Decoupling Technique For Compact Microstrip Antenna

The trend of array antenna miniaturization on phased array and multi-input-multi-output makes the decoupling technique for tight-spacing antenna becomes a necessary research focus.However,the current decoupling technique are faced with the problems of radiation pattern tilt and gain reduction.Therefore,this thesis researches the decoupling technique of a two-element microstrip antenna array with an edge-to-edge distance of0.05λ₀ and tight spacing along the H-plane,including the 3D wall decoupling technique with single frequency pattern correction,improving gain and correcting pattern over the bandwidth and planar decoupling technique.The main contents are as follows:1.Research on decoupling technique of double-layer 3D wall with single frequency pattern correction.The 3D wall structure with double dielectric layers separating the three symmetrical metal grounding layer is adopted to realize the decoupling between elements and the correction of the H-plane pattern of single frequency（5.8 GHz）.Among them,the middle metal layer adopts all-metal structure,and the outermost symmetrical metal layer is composed of two metal strips with inverted T-slots.In order to improve the gain,the outermost metal layer is changed to three metal strips,which can enhance the realized gain from-1.76 d B of the inverted T-slot to-0.24 d B under the condition of the pattern correction.2.Research on decoupling technique of single-layer 3D metal wall with single frequency pattern correction.The single dielectric layer structure is adopted to reduce the processing difficulty of the decoupling structure,and the antenna main dielectric substrate with small loss is used to improve the gain.The 3D wall decoupling structure is formed by etching symmetrical T-shaped metal strips on the dielectric substrate,which corrects the maximum radiation direction of the H-plane at 5.8 GHz to the broadside direction and produces the maximum realized gain of 4.93 d B.3.Research on the decoupling technique of single-layer dielectric 3D wall with intra-bandwidth pattern correction.Two n-shaped grooves with the same shape are etched on the symmetrical grounding metal layer.By adjusting the size of the grooves reasonably,destroying the original induced field distribution and forming a resonant structure,the correction of the H-plane pattern within the concerned operating bandwidth of 5.8 GHz can be realized.The measured results are in good agreement with the simulated results.The measured results show that the decoupling wall structure reduces the coupling coefficient over the bandwidth to below-30 d B.Compared with the no-decoupling structure,the maximum radiation direction of H-plane over the bandwidth is corrected from 22.5°～28.5°to-4.5°～3°,and the measured maximum realized gain of the H-plane is reduced by only 0.60 d B.4.Research on planar decoupling technique of single frequency pattern correction.The inverted"山"symmetrical planar metal decoupling structure is adopted to reduce the profile of the binary array,and the asymmetric metal via grounding technique is implemented on the symmetrical metal strips to improve the isolation of the excited antenna and correct the single frequency pattern.Then,a simple resonant metal strip structure is studied to realize the decoupling of the two antenna elements,and the beamwidth of the H-plane is flat within 50°,the fluctuation amplitude is only 0.2 d B,and the realized gain is 5.18 d B at 5.8 GHz.