The silicon die and copper lead-frame in IC packaging are bonded by die attach adhesive, and the quality of the interface is a critical issue in the reliability testing of IC packaging and during the manufacturing process. Common defects such as crack and delamination can be detected using C-mode ultrasonic microscopy method with sufficient confidence. However, weak interface due to weak adhesi...

Abstract— This work investigates the improvement of the active reflection coefficient of waveguide-fed phased-array antenna using liquid crystal layers. The anisotropy properties of liquid crystal layer can be employed to eliminate blind scan angle and improve the wide angle impedance matching of the waveguide-fed phased array antennas. The authors have expressed the modal analysis of the waveg...

The scattering of polarized light from a dielectric film sandwiched between two different semi-infinite dielectric media is studied experimentally and theoretically. The illuminated interface is planar, while the back interface is a two-dimensional randomly rough interface. We consider here only the case in which the medium of incidence is optically more dense than the substrate, in which case ...

The lowest-order nonlocal small slope approximation (NLSSA) reflection coefficient is derived, and numerical results are presented for one-dimensional (1-D) surfaces, satisfying the Dirichlet boundary condition. Reduction to the perturbation expression occurs in the small height limit, and the first term of the reflection coefficient gives the Kirchhoff approximation (KA) result. Numerical resu...

It is argued that depolarization of solar radio bursts requires reflection off boundary layers no thicker than about a wavelength (a few meters at most) between regions with large density ratios. The implied inhomogeneities suggest that the corona is much more highly and sharply structured than can be resolved from observations at other wavelengths. A simplified version of magnetoionic theory i...

Ultrasound parameters were proposed to characterize femur in vitro from rats. Six quantitative parameters (Apparent Integrated Ultrasonic Backscatter AIB, Frequency Slope of Apparent Backscatter – FSAB, Temporal Slope Apparent Backscatter TSAB, Integrated Reflection Coefficient IRC, Slope and Frequency Integrated Reflection FSIR and Temporal Slope Reflection Coefficient TSRC) were applied to th...

The propagation of small-amplitude waves in a thick-walled long viscoelastic tube of variable cross-section, filled with a viscous incompressible fluid, is considered with account for wave reflection at the tube end in application to arterial pulse wave propagation. A solution is obtained in the form of expansions in a small parameter. The effect of the coefficient of wave reflection at the tub...

We analyze the properties of line of sight (LOS) channels in vehicle-to-vehicle (V2V) communication. We use V2V measurements performed in open space, highway, suburban, and urban environments. By separating LOS from non-LOS data, we show that a two-ray ground reflection path loss model with effective reflection coefficient range fits the LOS channels better than the frequently used free space p...

A pulsed, 193 nm excimer laser is utilized to photoionize the organic gas tetrakisdimethylamino-ethylene ~TMAE!. The laser ionizes a plasma sheet with a width of 7.8 cm and an adjustable thickness of 0.7–1.4 cm. The axial scale length of the plasma density is a function of TMAE neutral pressure and is typically 50 cm. X-band ~10 GHz! microwaves are incident on the plasma with the electric field...

A number of applications, for instance ultrasonic imaging and nondestructive testing, involve the transmission of acoustic energy across fluid–solid interfaces into dissipative solids. However, such transmission is generally hindered by the large impedance mismatch at the interface. In order to address this problem, inhomogeneous plane waves were investigated in this work for the purpose of imp...