Current Issue : January - March Volume : 2017 Issue Number : 1 Articles : 6 Articles
Circularly polarized (CP) transparent microstrip reflectarray antenna is integrated with solar cell for small satellite applications at\n10GHz. The reflectarray unit cell consists of a perfect electric conductor (PEC) square patch printed on an optically transparent\nsubstrate with the PEC ground plane. A comparison between using transparent conducting polymers and using the PEC in unit-cell\nconstruction has been introduced.Thewaveguide simulator is used to calculate the required compensation phase of each unit cell in\nthe reflectarray.The radiation characteristics of 13 Ã?â?? 13 CP transparent reflectarray antenna are investigated. A circularly polarized\nhorn antenna is used to feed the reflectarray.The solar cell is incorporated with the transparent reflectarray on the same area.The\nsolar-cell integration with the reflectarray reduces the maximum gain by about 0.5 dB due to the increase in the magnitude of the\nreflection coefficient. The results are calculated using the finite integral technique (FIT)....
Nowadays, many types of materials are elaborated for microwave absorption applications.\nCarbon-based nanoparticles belong to these types of materials. Among these, graphene presents\nsome distinctive features for electromagnetic radiation absorption and thus microwave isolation\napplications. In this paper, the dielectric characteristics and microwave absorption properties of\nepoxy resin loaded with graphene particles are presented from 2 GHz to 18 GHz. The influence of\nvarious parameters such as particle size (3 Ã?¼m, 6ââ?¬â??8 Ã?¼m, and 15 Ã?¼m) and weight ratio (from 5% to 25%)\nare presented, studied, and discussed. The sample loaded with the smallest graphene size (3 Ã?¼m)\nand the highest weight ratio (25%) exhibits high loss tangent (tanÃ?´ = 0.36) and a middle dielectric\nconstant Ã?µ\n = 12ââ?¬â??14 in the 8ââ?¬â??10 GHz frequency range. As expected, this sample also provides the\nhighest absorption level: from 5 dB/cm at 4 GHz to 16 dB/cm at 18 GHz....
The rich potential of the microwave experiments for characterization and optimization of optical\ndevices is discussed. While the control of the light fields together with their spatial mapping at\nthe nanoscale is still laborious and not always clear, the microwave setup allows to measure both\namplitude and phase of initially determined magnetic and electric field components without significant\nperturbation of the near-field. As an example, the electromagnetic properties of an add-drop filter,\nwhich became a well-known workhorse of the photonics, is experimentally studied with the aid\nof transmission spectroscopy measurements in optical and microwave ranges and through direct\nmapping of the near fields at microwave frequencies. We demonstrate that the microwave experiments\nprovide a unique platform for the comprehensive studies of electromagnetic properties of micro- and\nnanophotonic devices, and allow to obtain data which are hardly acquirable by conventional optical\nmethods....
Microwave sensors in medical environments play a significant role due to the contact-less\nand non-invasive sensing mechanism to determine dielectric properties of tissue. In this work,\na theranostic sensor based on Split Ring Resonators (SRRs) is presented that provides two operation\nmodes to detect and treat tumor cells, exemplary in the liver. For the detection mode, resonance\nfrequency changes due to abnormalities are evaluated, and in the treatment mode, microwave\nablation is performed. The planar sensor structure can be integrated into a needle like a surgery\ntool that evokes challenges concerning size limitations and biocompatibility. To meet the size\nrequirements and provide a reasonable operating frequency, properties of oval shaped SRRs are\ninvestigated. By elongating the radius of the SRR in one direction, the resonance frequency can\nbe decreased significantly compared to circular SRR by a factor of two below 12 GHz. In order\nto validate the detection and treatment characteristics of the sensor, full wave simulations and\nmeasurements are examined. Clear resonance shifts are detected for loading the sensor structures\nwith phantoms mimicking healthy and malignant tissue. For treatment mode evaluation, ex vivo beef\nliver tissue was ablated leading to a lesion zone 1.2 cm Ã?â?? 1 cmÃ?â?? 0.3 cm with a three minute exposure\nof maximum 2.1 W....
Radiation pressure has recently been used to effectively couple the quantum motion of\nmechanical elements to the fields of optical or microwave light. Integration of all three\ndegrees of freedomââ?¬â?mechanical, optical and microwaveââ?¬â?would enable a quantum\ninterconnect between microwave and optical quantum systems.We present a platform based\non silicon nitride nanomembranes for integrating superconducting microwave circuits with\nplanar acoustic and optical devices such as phononic and photonic crystals. Using planar\ncapacitors with vacuum gaps of 60nm and spiral inductor coils of micron pitch we realize\nmicrowave resonant circuits with large electromechanical coupling to planar acoustic\nstructures of nanoscale dimensions and femtoFarad motional capacitance. Using this\nenhanced coupling, we demonstrate microwave backaction cooling of the 4.48MHz\nmechanical resonance of a nanobeam to an occupancy as low as 0.32. These results indicate\nthe viability of silicon nitride nanomembranes as an all-in-one substrate for quantum\nelectro-opto-mechanical experiments....
The design and results of investigation of the antenna array for\nground penetrating radar are presented. The antenna array is intended for\nmeasurement of the electrical properties of the road coating and finding of\nirregularities at monitoring the quality of roads. Antenna elements are\nmade by PCB technology on the plate of FR4. Each antenna element is\nplaced in a reflector formed by aluminum corner. The results of simulation\nin CST Studio Suite and the results of measurements of the characteristics\nof the antenna elements, and their mutual influence are presented. The\ndeveloped antenna array can be used at the ultrawideband pulse excitation,\nand at a scanning of continuous frequencies in the range of 0.5ââ?¬â??2 GHz....
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