Researches On Phased Antenna Array And Array Pattern Synthesis For Millimeter-Wave Applications

The increasing application demand in the fifth-generation(5G)mobile communication brings a great upsurge in the research interest in millimeter-wave(mm W)phased antenna array.The narrow half-power beamwidth of antenna elements,the large.adjacent spacing between elements,and the few element numbers have become three major barriers to wide-angle scanning phased antenna array for the 5G mm W applications.Based on the concept of array structure design,the research on two types of phased antenna arrays is carried out by using substrate integrated waveguide(SIW)H-plane horn and dual-polarization stacked patch antenna for one-dimensional scanning in the mm W frequency band.By modeling nonplanar phased antenna array synthesis as a mixed-integer programming problem,an array pattern synthesis algorithm is proposed.The details are as follows.1.Nonplanar wide-angle scanning phased antenna array for millimeter-wave applications: With SIW H-plane horn,a nonplanar phased antenna array is proposed by introducing the rearrangement of radiation apertures,then the isolations and the scanning range of the array antenna are greatly improved.Firstly,a 6×1 subarray is designed with an unequal six-way SIW power divider as feeding network,which keeps the low sidelobe level in H-plane.Finally,four 6×1 subarrays constitute the nonplanar 6×4 E-plane scanning phased antenna array.As shown in the measured results,the phased antenna array achieves a wide impedance bandwidth from 24.25 to 29.5 GHz,and good isolation above 18 d B.The proposed phased antenna array has a high gain of 15.55 d Bi in the end-fire direction and the 3-d B gain-drop scanning range is larger than ±60°.2.Dual-polarization stacked patch phased antenna array for millimeter-wave applications: With LTCC technology,a 1×4 stacked patch phased antenna array with ± 45°polarizations is designed for millimeter-wave applications.Firstly,the grounded stacked metal strips are proposed to suppress the surface electromagnetic wave in high dielectric constant material in elements design,improving the cross-polarization level.Finally,a selectively placing of floating stacked metal strips technique is adopted to improve the scanning performance of the proposed 1×4 phased antenna array.The simulated results show that the antenna array has a wide impedance bandwidth from 24.25 to 29.5 GHz and a broadside gain above 9.14 d Bi.The 3-d B gain-drop scanning range is greater than ± 50° in simulation and± 40° in measurement.3.Synthesis algorithm for nonplanar phased antenna array: A mixed-integer programming-based phased antenna array synthesis algorithm is presented to search the dynamic radiation patterns of the nonplanar phased antenna array.Firstly,a model is constructed,which determines the location of the main beam and gain.The sidelobe level constraint accounts for the non-main beam area pattern performance.Simplification of the model is done by taking the discrete property of the digital phase shifter into account,and the real coded genetic algorithm for solving mixed-integer optimization problems is introduced to array synthesis.The performance of the proposed phased antenna array synthesis algorithm is validated by two cases,which show the good performance and generalization possibility of the synthesis algorithm.