| Since the cylindrical dielectric resonator antenna(DRA)was introduced as a radiator by Long et al.in the 1980 s,DRA has been extensively studied and used due to its various advantages of wide band,low loss,and lightweight etc.Radio-frequency system-in-package(RF-SiP)is one of the most popular technologies for its versatility,miniaturization and low cost.Integrating transceiver antennas into the RF-SiP to form an antenna-in-package can further improve the integration density and working performance.The hollow DRA has excellent radiation performances and can reserve enough internal space for the packaging and integration of RF circuits,which makes it an ideal candidate for the development and application of dielectric resonant antennain-package(DRAiP).However,if RF circuits are directly exposed to the near field of the DRAiP,mutual interferences between the antenna and RF circuits cannot be avoided.Therefore,the radiation performances and shielding characteristics should be comprehensively considered in the DRAiP design.In addition,the differential antennas and circularly polarized(CP)antennas have good anti-interference performance,which can suppress common-mode noise and multipath scattering,and improve the stability and communication quality of the RF systems.In this paper,combining with the development and application of the antenna-inpackage technology,a variety of wideband DRAiPs with high shielding characteristics are proposed.At the same time,theoretical analysis and experimental tests are carried out on the electromagnetic interference(EMI)problems in packaging scenes.Several wideband differential or CP DRAs are also implemented based on new feeding structures.The main work and innovations of this thesis are summarized as follows:(1)By separating the feeding structure and packaging area,a probe-fed hollow DRAiP architecture with high shielding characteristic is proposed.The broadside or omnidirectional radiations of the DRAiPs are flexibly realized by changing the position of the feeding probe.Distinguished by whether the metal shielding cavity inside the hollow of the DRAiP exists,the impedance bandwidths and radiation characteristics of the antennas are studied and compared.By this means,the influences of the metal shielding cavity on the performances of the DRAiP are discussed.(2)In terms of EMI issues,the Baum-Liu-Tesche equation and hybrid S-parameter method are extended and applied to the calculation of induced voltages and currents at the terminals of complex RF circuits,which are caused by the near field of the antenna.The input-output characteristics and DC current variations of the low noise amplifier inside the hollow DRA with different near-field conditions are measured,and its coupling with the DRA are also tested.The EMI effects of the DRAiP on its packaged active circuits are studied,which provides an important reference for the packaging and integration of RF circuits and antenna.(3)A short-circuited stripline is introduced into the design of the top-fed DRAiP while considering the radiation performances and electromagnetic shielding characteristics of the antenna.The proposed top-fed structure is compatible with the flip chip soldering process,which facilitates the top packaging of RF circuits inside the antenna and improves the integration density of the system.When there are no metal shielding layers inside the hollow DRA,A wide impedance bandwidth of 31.7% is achieved by exciting the resonances of different parts of the DRA.While in the case of existing metal shielding layers,a closed metal cavity is formed by shielding layers and the bottom ground plane of the stripline.In this case,the DRAiP has an impedance bandwidth of 15.7% and provides more than 60 dB isolation for the internal packaging of highly sensitive chips.(4)A modified annular slot feeding structure is proposed.Based on this,an annular slot fed rectangular DRA with wide impedance bandwidth(20.6%)is realized and its working mechanism is explained in detail.Taking advantages of its annular planar structure,the modified slot is applied to the design of the rectangular DRAiP.In addition,a RF amplifier and filter chip are integrated into the hollow DRAiP and the coplanar design between the feeding structure and RF circuits is realized in the internalexternal packaging scene.The performance of the active integrated DRAiP is cosimulation and tested.The packaging difficulty is greatly reduced while maintaining integration density by this means.(5)To increase the impedance bandwidth of microstrip-fed DRA,a novel parallel microstrip feeding structure is proposed to excite the fundamental TE mode of rectangular DRAs with low permittivity.By introducing the resonance of the microstrip feeder,a wideband differential DRA with an impedance bandwidth of 22.4% is firstly designed.Then,based on the DRA unit,a differentially fed DRA array combining series and parallel feedings is implemented for the first time.In addition,the bandwidth of the array is successfully increased to 30.4% from 18.9% by introducing the defected ground structure.Finally,a third-order wideband dielectric resonator filtering antenna is designed combining the resonances of the microstrip feeder and DRA.Good in-band flatness and out-of-band rejection are obtained.(6)By embedding the substrate and feeding structure into the DRA,a highly integrated and wideband(49.7%)linearly polarized DRA supporting three resonant modes is proposed.The in-band gain of the antenna is up to 8.56 dBi and a good broadside radiation is ensured within the bandwidth.This compact antenna is very situable for the vertical stacked antenna-in-package design.A cross-slot feeding structure is then introduced to extend the LP DRA into a single-fed CP one.In order to broaden its axial ratio(AR)bandwith,the artificial ground structure is added into the CP antenna.As a result,its AR bandwidth is increased dramatically from 6.2% to 31.0% and the in-band gain is improved correspondingly.The application of the supersurface in the design of CP DRA is proved. |
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