טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentShvartzman Lior
SubjectOptimization of Power Absorption in a Thin Periodically
Loaded Slab
DepartmentDepartment of Electrical Engineering
Supervisor Professor Pinchas Einziger


Abstract

The phenomenon of electromagnetic power absorption in a thermal detector array has recently become of increased scientific interest. That is when there’s a need to design such array for conversion of electromagnetic signal from a distant object, into electric signal. The main advantage of the thermal (bolomter) detectors over the alternative quantum detectors, is that there’s no need of cryogen, which increases the price of the system by significant order. Especially there’s an increasing interest in the millimeter size wavelength range for a variety of applications that demand ability to penetrate foggy and smoky environment or clothes for weapon detection. At this wavelength range it is not possible to design devices depending on the geometric optics principles (quassi-optics), and that is why there’s a need to find another model based on Maxwell equations, that will enable efficient design of these devices. In general it is possible to solve such problems using accepted methods for electromagnetic problem solution. Nowadays these methods are mainly established on numerical techniques using computer resources. We, however, focus on a relatively simple analytic model but with the ability to provide deep insight into design principles of the bolometric detector array, using two main methods, which are each suited to another spectral range. The first method is suited to a frequency range in which the wave length is much smaller then the typical length of a single detector (quassi-optics spectral range), for which we assume that every detector is in fact a separate object from its neighbor, and as such it has to be designed in separately in order to get optimal performance (maximum absorbed power). The second method, however, is suited to a lower spectral range (millimeter wave length), in which the last assumption to the typical dimension of the detector is not valid and in a certain amount is even contradicting (quassi-static spectral range). This method is based on a model that presumes the array consists of an infinite amount of detectors made of highly electrical loss material, and its shape is infinite length narrow width (refers to wave length) cylinder. Both methods utilize mainly analytic techniques for the problem’s investigation, and the emphasis is given to finding simple explicit equations, which take into account the varying dependence on the deferent parameters in the problem.