In this paper, we investigate a novel fast and reliable method to check the bonding quality of silicon wafers. It
is based on illuminating the wafers with a high frequency waves (110 - 170 GHz) using quasi-optical technique.
The reflected energy is used to evaluate the bonding strength. The reported experimental study is compared
with the Infrared images.
The assessment of the performances of ground-penetrating radar (GPR)
in humanitarian demining is an important problem. These performances
are related to the relative strength of the target radar response with respect to that of the soil. Many parameters influence both responses. The physical and geometrical parameters that influence the target signature include the soil electromagnetic (EM) constitutive parameters, the target depth and orientation with respect to the soil surface, the antenna height and the target EM and geometrical properties.
This work presents a numerical parametric study of the soil and target radar signatures. The advantages of the numerical approach are: it allows for a separate study of the influence of each parameters on the radar responses, it is fast, cheap, generic with regards to hardware, and finally it is not prone to experimental errors and hardware failures or misuse. Moreover it is always possible to link the numerical experiments with a particular hardware by characterizing this latter. However, a number of simplifications, such as modeling the soil as a planar multilayered medium, are introduced to keep the problem tractable.
This study yields surprising results, such as for example the possibility of considering the target in homogeneous space for computing its signature, as soon as it is a few centimeters deep. The target considered in the numerical experiments is a dielectric cylinder representing an AP mine, with diameter 6 cm and height 5 cm, and εrt=3. These values are chosen to approach as much as possible the physical properties of the M35BG AP mine, which is small and therefore difficult to detect.
Lumped circuit and 3D-electromagnetic models are presented for a photo-induced plasma that induces local changes in the dielectric properties of a coplanar waveguide transmission line to switch millimeter waves, propagating along transmission lines on BCB coated high resistive silicon substrates. Measurements up to 110 GHz are compared with the various developed models. The insertion loss of these transmission lines was only 1 dB/mm at 100 GHz. The modulation of S21 was about 40 dB at 110 GHz for an optical power of 60 mW focused on one slot between signal and ground. S11 could only be fitted with a lumped circuit model when introducing a frequency dependent impedance was introduced.