Wideband and polarisation-independent antireflection coating using metamaterials

, Article IET Optoelectronics ; Volume 14, Issue 5 , 2020 , Pages 266-273 Sepehripour, F ; Karimi, P ; Khavasi, A ; Sharif University of Technology

Institution of Engineering and Technology 2020

Abstract

Here, the authors propose a new approach for realising wideband and polarisation-independent antireflection coating, based on a metamaterial composed of a subwavelength array of metallic pillars with a square cross-section. The effective impedance of the array can be duly adjusted by the size and distance of the pillars. As such, the authors design the effective impedance of the antireflection coating to be the geometrical mean of the impedance of upper and lower media and choose its height to be quarter of operating wavelength. Doing so, the reflection vanishes at the desired frequency and fractional bandwidth of 56% is achieved with a criterion of 10% reflectance (the refractive index of...

Design and Implementation of Amplitude Detection Method for Millimeter Wave Imaging

, M.Sc. Thesis Sharif University of Technology Sepehripour, Fahimeh (Author) ; Khavasi, Amin (Supervisor) ; Fakharzadeh, Mohammad (Co-Supervisor)

Abstract

Conventional imaging systems composed of two linear arrays of antennas as a transmitter and receiver. These arrays of antennas electronically scan along their antenna elements and are mechanically moved along a second orthogonal direction for scanning large two-dimensional areas quickly. In this thesis, the transmitter antenna elements are Tapered slot-line Antenna operating at 20-30GHz. A multiplexer circuit is used to transmit wideband signals to each antenna in the array. The receiver is composed of Schottky diode and pick up antenna that they are printed onto the radiating end of the antennas on the edge of the transmitter circuit board.In the available imaging systems, for achieving the...

Principles of Designing a Chair for Iranian Kitchen, Concerning Kansei Engineering Approach

, M.Sc. Thesis Sharif University of Technology Khyat Ardestani, Fahimeh Sadat (Author) ; Eshraghniaye Jahromi, Abdolhamid (Supervisor) ; Sadeghi Naeini, Hassan ($item.subfieldsMap.e)

Abstract

Iranian women spend a lot of times in the kitchen area in order to have good effects on the family. Unfortunately, we see many of them are suffering from body injuries and particularly musculoskeletal disorders in their middle ages. Many factors cause such problems among which awkward postures are mentioned and with identifying these postures, corrective solutions could be proposed.In this study, firstly, relationship of body injuries with working in the kitchen area is considered, awkward postures are identified and expedient actions are suggested. The aim of this study is chosen designing a suitable task chair for kitchen among the proposed solutions. Then, chair specifications are...