Research On 5G Millimeter Wave Antenna In Package

5G millimeter-wave band（24.5-29.5GHz）featuring high frequency and wide absolute bandwidth has the advantages of large capacity,high speed,and low delay.Therefore,it has attracted extensive attention in both industry and academia.In particular,with the development of 5G millimeter-wave communication,the development of mobile communication devices is towards high integration,which in turn puts forward higher requirements on antenna size.Antenna in package（Ai P）conforms to the trend and has become the mainstream solution for millimeter-wave wireless systems.Due to the unique application scenarios of the 5G terminal（such as mobile phones）,there are special requirements for millimeter-wave antennas,such as high gain,low profile,high efficiency,and broadband（covering 5G millimeter-wave band）.Therefore,it is important to carry out the research on the 5G millimeter-wave Ai P according to these requirements.The main work contents of this article include:1.A millimeter-wave ultra-low profile broadband antenna based on log-periodic patches:Based on the working principle of the log-periodic antenna,the meander line is used to feed the patch in series to control the electric distance between the patches.The size and spacing of the patch are inctreased according to a specific proportion coefficient.At the same time,the proportion coefficient of low frequency is adjusted to compensate that the small thickness of the dielectric substrate does not change with frequency to achieve the effect of ultra-low profile broadband.The simulation and measured results show that the whole 5G millimeter-wave band（24.25-29.5GHz）is covered under the condition of a profile of0.254mm（0.02λ₀）with a full ground.The impedance bandwidth is more than 20%,and the gain in the band is more than 9.5d Bi.It is proven that the antenna has the characteristics of ultra-low profile,broadband,and is suitable for millimeter-wave terminal antenna.2.Millimeter wave high gain planar aperture antenna element and array:the antenna element adopts SIW slot feed,expands the aperture field through the surface wave,and then uses the cavity wall and top cross metal patch to control the distribution of the surface aperture field.By shielding the inverse electric field and adjusting the size of the rectangular radiation slot,the uniform in-phase distribution of the aperture electric field is ensured,and the planar aperture antenna unit with high gain and high aperture efficiency is realized.On this basis,multiple planar aperture antenna elements are used to form an array to improve the antenna gain further.The simulation and measured results show that the gain of the planar aperture antenna element can reach 19d Bi,and the impedance bandwidth is 26.2-29.5GHz（12.2%）;The 4×4-element array has a gain of 26.7d Bi,aperture efficiency of 71.6%,impedance bandwidth of 25.9-29.6GHz（13.3%）,and can cover 5G millimeter-wave n257band.It is proved that the planar aperture antenna and array have the advantages of high gain and high aperture efficiency and thus are suitable for millimeter-wave point-to-point communication.3.Millimeter wave package-substrate distributed antenna:Based on the idea of distributed antenna,the Yagi antenna structure is distributed in package（feed）and substrate（deflector）.Using the substrate structure to obtain a large antenna aperture to ensure a high gain or effectively control the aperture field to realize beamforming and reduce the interconnection loss between the package and the substrate to ensure the radiation efficiency.LTCC and PCB processes are used to realize the distributed antenna structure on the package and substrate,respectively.With this scheme,the same package feed can be used with different deflector substrates according to different application scenarios to obtain different performance such as high gain or shaped pattern,achieving the package reuse.Therefore,based on the same package feed structure,combined with the design of two different substrate deflectors,two different package substrate distributed antennas are realized.The simulation and measured results show that the impedance bandwidth of the high gain package substrate antenna is 25.1-29.6GHz（16.45%）,and the gain is greater than 10d Bi;The impedance bandwidth of the distributed antenna on the shaped beam package substrate is 26.5-29.5GHz（10.7%）.It is proved that the design scheme of the packaging substrate distributed antenna is feasible and suitable for 5G millimeter-wave applications.