Sensitivity of Dielectric Substrate Property Discrepancy and Metal Microstrip Roughness to the Electronic Characteristics of Antenna-in-Packaging for 5G Applications at Millimeter-Wave Frequencies

Realization of Antenna-in-Package (AiP) needs to resolve several performance instability challenges at millimeterwave (mmW) frequencies. They are caused by the uncertainties of material properties and mechanical fabrication limitations. In particular, the material properties are highly dependent on frequencies and may exhibit properties of magnetization. Besides, the physical sizes of wavelength at mmW frequencies are very small, making the discrepancy by mechanical fabrications large to cause degradation to the AiP's radiation performance. The roughness of the metal surface may also cause performance degradation, which cannot be avoided due to adherence to the dielectric substrates. These potential performance degradation factors are examined in this paper by considering practical AiPs at 38 GHz bands. Comparisons between full-wave simulations and experimental measurements over AiP prototypes are performed to justify materials and fabrications' influencing factors.