Simon Behboudi Amlashi

Salman Behboudi Amlashi


Postgraduate Research Student

Academic and research departments

Department of Electrical and Electronic Engineering.

My research project

My publications

Publications

Vikrant Singh, Mohsen Khalily, Salman Behboudi Amlashi, J. David Carey, Rahim Tafazolli (2020)Fully-Transparent Transmission Surface for Outdoor-Indoor mmWave Coverage Enhancement, In: 5th International Conference on UK-China Emerging Technologies (UCET)

This paper presents a fully-transparent and novel frequency selective surface (FSS) that can be deployed instead of conventional glass to reduce the penetration loss encountered by millimeter wave (mmWave) frequencies in typical outdoorindoor (O2I) communication scenarios. The presented design uses a 0:035 mm thick layer of indium tin oxide (ITO), which is a transparent conducting oxide (TCO) deposited on the surface of the glass, thereby ensuring the transparency of the structure. The paper also presents a novel unit cell that has been used to design the hexagonal lattice of the FSS structure. The dispersion and transmission characteristics of the proposed design are presented and compared with conventional glass. The presented FSS can be used for both 26 GHz and 28 GHz bands of the mmWave spectrum and offers a lower transmission loss as compared to conventional glass without any considerable impact on the aesthetics of the building infrastructure.

Sajad Niknam, Mehran Yazdi, Salman Behboudi Amlashi, Mohsen Khalily (2020)Numerical Performance Analysis of Terahertz Spectroscopy Using an Ultra-Sensitive Resonance-Based Sensor, In: Frontiers in Physics8pp. 1-7 Frontiers Media

A terahertz sensor structure is proposed that can sense any variations in analyte permittivity. The sensor essentially works according to the shifts in the resonance frequencies of its propagated spoof surface plasmonic modes. The proposed structure shows great support for surface plasmon oscillations, which is proved by the calculated dispersion diagram. To achieve this in terahertz frequencies, a metamaterial structure is presented in the form of a structure with two-dimensional periodic elements. Afterward, it is shown that the performance of the sensor can be affected by different parameters such as metal stripe thickness, length of metal stripe, and width of metal stripe as the most influential parameters. Each of the parameters mentioned can directly influence on the electric field confinement in the metal structure as well as the strength of propagation modes. Therefore, two propagation modes are compared, and the stronger mode is chosen for sensing purposes. The primary results proved that the quality factors of the resonances are substantially dependent on certain physical parameters. To illustrate this, a numerical parametric sweep on the thickness of the metal stripe is performed, and the output shows that only for some specific dimensions the electromagnetic local field binds strongly with the metal part. In a similar way, a sweeping analysis is run to reveal the outcome of the variation in analyte permittivity. In this section, the sensor demonstrates an average sensitivity value, ~1,550 GHz/Permittivity unit, for a permittivity range between 1 and 2.2, which includes the permittivity of many biological tissues in the terahertz spectrum. Following this, an analysis is presented, in the form of two contour plots, for two electrical parameters, maximum electric field and maximum surface current, based on 24 different paired values of metal thickness and metal width as the two most critical physical parameters. Using the plotted contour diagrams, which are estimated using the bi-harmonic fitting function, the best physical dimension for the maximum capability of the proposed sensor is achieved. As mentioned previously, the proposed sensor can be applied for biological sensing due to the simplicity of its fabrication and its performance.

SALMAN BEHBOUDI AMLASHI, MOHSEN KHALILY, VIKRANT SINGH, PEI XIAO, JAMES DAVID CAREY, RAHIM TAFAZOLLI (2021)Surface Electromagnetic Performance Analysis of a Graphene-Based Terahertz Sensor Using a Novel Spectroscopy Technique, In: IEEE journal on selected areas in communications : a publication of the IEEE Communications Society Institute of Electrical and Electronics Engineers (IEEE)

In this paper, a novel terahertz (THz) spectroscopy technique and a new graphene-based sensor is proposed. The proposed sensor consists of a graphene-based metasurface (MS) that operates in reflection mode over a broad range of frequency band (0.2 -6 THz) and can detect relative permittivity of up to 4 with a resolution of 0.1 and a thickness ranging from 5 μm to 600 μm with a resolution of 0.5 μm. To the best of author’s knowledge, such a THz sensor with such capabilities has not been reported yet. Additionally, an equivalent circuit of the novel unit cell is derived and compared with two conventional grooved structures to showcase the superiority of the proposed unit cell. The proposed spectroscopy technique utilizes some unique spectral features of a broadband reflection wave including Accumulated Spectral power (ASP) and Averaged Group Delay (AGD), which are independent to resonance frequencies and can operate over a broad range of spectrum. ASP and AGD can be combined to analyse the magnitude and phase of the reflection diagram as a coherent technique for sensing purposes. This enables the capability to distinguish between different analytes with high precision which, to the best of author’s knowledge, has been accomplished for the first time.