Development and mechanical modeling of Si1-XGex/Si MQW based uncooled microbolometers in a 130 nm BiCMOS

This paper presents the development of process integration and mechanical modeling of a Si1-xGex/Si MQW based uncooled micro-bolometer. The recent progress on layer transfer based integration scheme of Si1-xGex/Si based micro-bolometer into a 130 nm BiCMOS process is presented. The two important parts of the process integration, namely the layer-transfer and stress compensation of the arms are studied. The initial successful results on layer transfer and the FEM modeling for the stress compensation of the thin and narrow arms of the bolometer is presented. Finally, the developed FEM model is compared with the fabricated cantilevers. The results show that the developed FEM model has a very good matching with the experimental results; thus very convenient to use for the FEM modeling of the full bolometer structure

Design of a microwave lens for 5G applications

This thesis proposes a novel, low-cost, multilayer Rotman lens and antenna array for 5G applications at 28GHz band. The final design consists of a multilayered Rotman Lens, with the antenna array on the front and the Rotman Lens on the backside of the board. The lens and array are connected by slots opened to the common ground layer that is between them. This two layered structure made it possible to reduce the total footprint of the design. These slots were designed so that the insertion loss through them is less than 1dB. The design of the dummy ports found on the sides of the Rotman Lens was also changed. The dummy ports require 50Ω terminations to reduce the reflections occurring on the sidewalls to prevent unwanted phase shifts. The dummy ports were terminated using quarter wave transformation techniques. Using the quarter wave transformations, the dummy ports were matched to 200Ω. These transmission lines were paired in two so that they are each matched to 100Ω and require 100Ω terminations to These connections were done so that they act as terminations to each other. These connections made it possible to remove the 50Ω connectors necessary to reduce the sidewall reflections. This way, the size and cost of the design was lowered further. Conventional Rotman Lens designs can produce beams equal to the number of beam ports it has. The feeding network of the lens was designed using in-phase transmission lines, allowing multiple inputs to be fed together to generate two extra beams. The measured beams have gains between 9.2 and 13.7dBi. The beams cover an area of 80◦, with a 3dB bandwidth of 2GH

Anayol yakınında yaşayan sığırlarda kan ağır metal, iz element seviyeleri ve antioksidan metabolizma arasındaki ilişkinin değerlendirilmesi

In this study, detection of a possible relationship of some trace element levels of copper (Cu), zinc (Zn), and iron (Fe), toxic heavy metals, cadmium (Cd) and lead (Pb), and antioxidant functions in cattle, which are living near the trunk roads for at least 3 years, was aimed. Totally, 70 cattle, which were in diff erent herds, were used. Fifty-four cattle (3-13 years), which were living near the trunk roads at about 0-500 m were used for the experiment group. Also, 16 cattle (3-12 years), which were living far from trunk roads at about 2-3 km were used for the control groups. Blood samples were collected and Cd, Pb, Cu, Zn, Fe levels, lipid peroxidation product malondialdehyde (MDA) and antioxidative defense system indicators, erythrocyte superoxide dismutase (SOD) activity, catalase (CAT) activity, and plasma ceruloplasmin (CP) level were measured. Cd and Pb levels of the experimental animals were determined to be higher than the control group (P&lt;0.01 and P&lt;0.001, respectively). However, Zn level of the experiment group was found lower than the control animals (P&lt;0.001). MDA increased about three times and CP increased about two times more than the control group (P&lt;0.001). Significantly correlations were observed among Pb, MDA and CP levels. Also, important correlations were found between Fe and CP, also Cu and MDA levels. Besides, MDA and CAT levels of the animals increased with CP and SOD together, respectively. At the end of the study, Cd and Pb accumulation was observed in cattle, which were living near the road with intensive traffic for at least three years when compared with the control group. In addition, the results showed significant interactions among toxic heavy metals, physiological trace elements, enzymatic and non-enzymatic antioxidants and the lipid peroxidation.Bu çalışmada, en az 3 yıldır anayol kenarında yaşayan sığırlarda bakır (Cu), çinko (Zn) ve demir (Fe) gibi bazı iz elementler, zehirli ağır metallerden olan kadmiyum (Cd) ve kurşun (Pb) ve antioksidan fonksiyonlar arasındaki olası ilişkinin tespit edilmesi amaçlandı. Çalışmada farklı ahırlarda yaşayan toplam 70 besi sığırı kullanıldı. Ana yola 0-500 metre mesafede yaşayan 54 (3-13 yaşlarında) sığır araştırma grubu olarak kullanıldı. Ana yola 2-3 km mesafede yaşayan 16 (3-12 yaşlarında) sığır ise kontrol grubunu oluşturdu. Hayvanlardan kan örnekleri toplandı ve Cd, Pb, Cu, Zn, Fe seviyeleri, lipid peroksidasyon göstergesi olan malondialdehid (MDA) ve antioksidasyon defans sistem indikatörleri olan eritrosit süperoksit dismutaz (SOD) aktivitesi, katalaz (CAT) aktivitesi ve plazma serüloplazmin (CP) seviyesi ölçüldü. Deneme grubu hayvanların Cd ve Pb seviyelerinin kontrol grubu hayvanlardan yüksek olduğu belirlendi (sırasıyla P<0.01 ve P<0.001). Bununla birlikte deneme grubunun Zn seviyesi kontrol grubundan düşük bulundu (P<0.001). MDA seviyesi kontrol grubundan yaklaşık üç kat, CP seviyesi ise yaklaşık iki kat daha yüksek tespit edildi (P<0.001). Pb ile MDA ve CP seviyeleri arasında gözle görülür şekilde bir ilişki olduğu gözlendi. Ayrıca, Fe ile CP ve Cu ile MDA arasında da önemli ölçüde korelasyon bulundu. Bunun yanında MDA ile CAT ve CP ile SOD seviyelerinin birlikte yükseldiği görüldü. Çalışma sonunda, anayol yakınında en az üç yıl yaşamış olan hayvanlarda, kontrol grubuyla karşılaştırıldığında Cd ve Pb birikimi olduğu gözlendi. Ayrıca, elde edilen sonuçlar zehirli ağır metaller, fizyolojik iz elementler, enzimatik ve enzimatik olmayan antioksidanlar ve lipid peroksidasyon göstergesi olan MDA arasında önemli düzeyde ilişki olduğunu gösterdi

FEM modeling of microbolometer structures

This paper presents different geometrical designs for microbolometer in order to analyze mechanical and thermal behavior of the device. The simulations are performed on amorphous silicon based microbolometers with a pixel size of 12 micrometer x 12 micrometer by using finite-element-method (FEM) solver, ANSYS(r). The design differences are basically the change of the arm's length of the microbolometer, namely, half-sided, one-sided, and two-sided. The arm structures are consisted of three layers; silicon nitride/titanium nitride/silicon nitride (Si3N4/TiN/Si3N4). The mechanical part of simulations consisted of implementing residual stresses that arise after the deposition on different microbolometer models. The output from the mechanical simulations is the determination of deformations for X-Y, and Z planes and the total stress. The thermal-electric modeling provides thermal conductance while transient thermal modeling is used for the thermal time constant extraction. The simulations prove the mechanical stability and performance which is in a good agreement with the fabricated different designs of microbolometer