| In recent years,safe driving has been a major concern,so the market for 77 GHz in-vehicle radar systems as a core part of driver assistance systems is growing rapidly.But traditionally most of the in-vehicle radar packaging applications,integrating antennas into printed circuit boards will generate significant parasitic effects due to chip-package-board interconnections.The embedded Wafer Level Ball Grid Array(eWLB)packaging technology can effectively reduce the package to board transmission loss and parasitic effect by implementing the antenna through the Redistribution Layer(RDL)in the package.This paper revolves around an Antenna-in-Package in automotive radar design based on eWLB technology to integrate the antenna into the top RDL of the package structure.Major tasks of this paper are listed as follows:(1)Determining the vertical interconnect structure introduced in this paper to design the new Antenna-in-Package.Equivalent model analysis and high frequency electromagnetic simulation of TEV and EZL two vertical interconnection structures,the results show that EZL structure can cover the size and impedance range of TEV structure,and the performance of return loss and insertion loss of EZL structure is better than TEV structure under 77 GHz high frequency simulation,so EZL structure is chosen as the vertical interconnection structure of the new Antenna-in-Package designed in this paper.(2)Design study of an Antenna-in-Package in automotive radar with antenna integrated in the top RDL.Based on the NXP TEF810 X vehicle radar package solution,the overall structure of the new Antenna-in-Package is designed,then the folded dipole antenna working in 77 GHz vehicle radar band is designed according to the requirements,the simulation results show that the working band is 75.91-80.85 GHz,the maximum gain is 7.90 d Bi,finally the designed folded dipole antenna is integrated into the overall structure of the Antenna-inPackage.The simulation results show that the working band is 74.69-80.01 GHz,and the maximum gain is 6.40 d Bi.(3)Optimization study of Antenna-in-Package in automotive radar.A parallel-fed folded dipole antenna packaged antenna array is designed based on the packaged antenna unit already designed in this paper,and the simulation results show that the maximum radiation gain of the array is 9.30 d Bi,which is increased by 2.90 d Bi with the unit,.A dielectric coating is added to improve the radiation focusing performance of the packaged antenna,and a metal reflection strip is added around the antenna element to compensate for the gain reduction caused by the dielectric coating.By comparing and analyzing the radiation performance of the designed new packaged antenna and the traditional single RDL packaged antenna,the maximum radiation gain is increased by 3.54 d Bi,and the improvement range is 61.3%.The advantages of the multi-RDL packaged antenna structure in improving the antenna radiation performance are described.And design a miniaturized Antenna-in-Package with a package size of 6mm×6mm.The simulation results show that the operating frequency band is 75.13-80.05 GHz,the operating bandwidth is 4.92 GHz,and the maximum gain is 9.42 d Bi,which meets the performance requirements of the vehicle radar antenna,and the package area is reduced by 43.75%.This paper designs a new packaged antenna structure based on eWLB technology that integrates the antenna into the RDL on the top of the package structure,which effectively reduces the transmission loss and parasitic effect from the package to the board.The introduction of EZL vertical interconnection to form a three-dimensional structure reduces the coupling parasitic effect between the antenna and the chip,improves the radiation performance of the antenna,enhances the design flexibility of the packaged antenna,helps to further reduce the overall size of the packaged antenna,and has greater application scenarios under the design requirements of high-performance and miniaturized vehicle radar systems. |
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