Maryam Khodadadi
@sutech.ac.ir
5G and 6G Innovation Centres (5GIC and 6GIC), Institute for Communication Systems (ICS), University of Surrey, Guildford, UK
Research Fellow in Metasurface Engineering
Maryam Khodadadi, (Member, IEEE, was born in Tehran, Iran in 1988. She earned her B.Sc. and M.Sc. degrees in computer engineering and telecommunication engineering from K. N. Toosi University of Technology, Tehran, Iran, in 2011 and 2015, respectively. She later obtained her Ph.D. in telecommunication engineering from Shiraz University of Technology, Shiraz, Iran, in 2020. From 2020 to 2022, she conducted postdoctoral research on controllable hybrid plasmonic integrated circuits with the Shiraz University of Technology. During this period, she received a research fellowship from the Iran National Science Foundation (INSF). Since 2023, she has held a postdoctoral research associate position at the Institute for Communication Systems (ICS) at the University of Surrey, UK, a home to the 5G and 6G Innovation Centres (5GIC and 6GIC). She has conducted extensive research in Flexi DAS and Reconfigurable Intelligent Surfaces (RIS). Her diverse research interests include hybrid plasmonic nano
RESEARCH, TEACHING, or OTHER INTERESTS
Electrical and Electronic Engineering, Computer Engineering
Scopus Publications
Scholar Citations
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Scholar i10-index
Scopus Publications
Maryam Khodadadi, Seyyed Mohammad Mehdi Moshiri, Najmeh Nozhat, and Mohsen Khalily
Springer Science and Business Media LLC
AbstractIn this paper, a controllable hybrid plasmonic integrated circuit (CHPIC) composed of hybrid plasmonic waveguide (HPW)-based rhombic nano-antenna, polarization beam splitter, coupler, filter, and sensor has been designed and investigated for the first time. In order to control the power into a corresponding input port, a graphene-based 1 × 3 power splitter with switchable output has been exploited. The functionality of each device has been studied comprehensively based on the finite element method and the advantages over state-of-the-art have been compared. Moreover, the effect of connection of CHPIC to the photonic and plasmonic waveguides has been studied to exhibit the capability of variety excitation methods of the CHPIC. Furthermore, the performance of the proposed CHPIC connected to inter/intra wireless transmission links has been investigated. The wireless transmission link consists of two HPW-based nano-antennas as transmitter and receiver with the maximum gain and directivity of 10 dB and 10.2 dBi, respectively, at 193.5 THz. The suggested CHPIC can be used for applications such as optical wireless communication and inter/intra-chip optical interconnects.
Maryam Khodadadi, Seyyed Mohammad Mehdi Moshiri, Najmeh Nozhat, and Mohsen Khalily
Optica Publishing Group
In this paper, for the first time, the idea of a dielectric director has been utilized to improve the directivity and gain of the proposed hybrid plasmonic rhombic nano-antenna (HPRNA). The proposed HPRNA can support a horizontal radiation pattern to flourish the concept of wireless transmission link. The horizontal radiation pattern has a 3 dB beamwidth of 43.5°, side lobe level of −11.9 dB, and a directivity and gain of 10.5 dBi and 10.3 dB, respectively, at the operating frequency of 193.5 THz. Moreover, the effects of geometric parameters to verify the functionality of the proposed nano-antenna have been investigated. Finally, the idea of an on-chip wireless transmission link based on transmitting and receiving HPRNAs has been developed and studied theoretically and numerically. The fabrication of the proposed nano-antenna can be done by the typical e-beam lithography (EBL) technique, which is easier than the complicated X-ray method because of its suitable aspect ratio.
Maryam Khodadadi, Mohsen Khalily, Zahra Davoodirad, Ahmed A Kishk, and Alireza Mallahzadeh
IEEE
This paper presents a novel leaky-wave antenna based on utilizing the high bandwidth and low loss ridge gap waveguide concept, featuring a cosecant squared radiation pattern. The antenna is designed to operate within the frequency range of 25 GHz to 29 GHz. At the center frequency of 28 GHz, the antenna achieves a maximum gain of 10 dBi. Additionally, at a frequency of 28.8 GHz, the antenna exhibits a maximum return loss of -16.9 dB. Moreover, the proposed leaky-wave antenna demonstrates the potential of the radiation technology for 5G systems by enabling scanning angles ranging from approximately 5° to 20° across the specified frequency range. This feature highlights the versatility and suitability of the antenna for various applications in 5G communication systems.
Shakila Karami, Maryam Khodadadi, and Nosrat Granpayeh
IEEE
Photodetectors convert the optical signal into a proportional electrical current. Based on the vector nature of light, Photodetectors are designed to detect power and can be used in circuits to sense incident angle of radiant light. In this paper, a novel photodetector based on using two parallel circular metal-semiconductor-metal has been proposed which measure simultaneously the power and incident can angle of light. Each of these photodetectors is made of a silicon nanowire placed by thin gold tubes on a silicon oxide substrate. Examination of the absorption spectrum reveals that different resonances occur in the visible light spectrum. Therefore, because of the short distance between two nanowires, similar resonant modes are coupled with each other. The behavior of resonant modes can introduce based on the coupling mode theory. Assuming light illumination on the structure, the angle of incident light is obtained which is related to some factors including (1) the relationship between the ratio of energy stored in nanowires, (2) the parameters extracted from the coupled mode theory, (3) the wavelength of resonant mode, (4) the wavelength of radiant light, and (5) the distance between photodetectors. In addition, the total power is obtained by gathering the amount of absorbed power from each nanowire. The proposed structure acts as a simple and extremely small light sensors which shows more information about the environment and could be exploited in the next-generation of smart optoelectronic and artificial intelligence systems in order to design the imaging devices, 3D positioning, autonomous vehicles, and in robotics.
Maryam Khodadadi, Najmeh Nozhat, and Seyyed Mohammad Mehdi Moshiri
Elsevier BV
Mohammad Sadegh Zare, Najmeh Nozhat, and Maryam Khodadadi
Springer Science and Business Media LLC
Seyyed Mohammad Mehdi Moshiri, Najmeh Nozhat, and Maryam Khodadadi
IOP Publishing
Abstract In this paper, for the first time, a dynamic tunable graphene-based cross Yagi–Uda antenna in the terahertz region has been investigated comprehensively by two numerical methods and analytical analysis. To verify the accuracy of the analytical solution based on the coupled dipole method to obtain the directivity pattern, two numerical methods of finite-element and finite-difference time-domain have been used. Numerical results are well matched with the theoretical ones. By introducing the tunable cross Yagi–Uda antenna with graphene-coated spheres, different directivity radiation patterns such as omni-, vertical and horizontal bi- and quad-directional have been obtained with the maximum directivities of 2.42, 12.4, 12.3, and 10.5 dBi, respectively. Moreover, the effect of different element shapes including cube and cylinder on the directivity and radiation efficiency has been studied. Also, the new idea of multiple-access and controlling the user’s access to the radiated optical electromagnetic waves from the transmitting antenna has been studied as an optical wireless on-chip link. Finally, the effect of structural parameters on the directivity of the proposed antenna has been surveyed with the tolerance of ±5% to investigate the imperfections that may appear in the fabrication process.
Maryam Khodadadi and Najmeh Nozhat
Institute of Electrical and Electronics Engineers (IEEE)
The characteristics of a super-mode waveguide-fed nano-antenna composed of a complementary triangular hybrid plasmonic radiation part have been investigated by two methods of finite element and finite-difference time-domain. Also, a symmetric hybrid plasmonic waveguide (SHPW) has been studied theoretically and numerically to analyze short- and long-range fundamental TM super-modes (TMSR and TMLR) that excite the nano-antenna. The obtained propagation length and figure of merit at 193.5 THz are 150.6 μm (1.27 μm) and 691.77 (16.94) for TMLR (TMSR) super-mode, respectively, which confirm the inevitable loss-confinement trade-off of SHPW. These super-modes cause the nano-antenna to have horizontal and bidirectional radiation patterns due to the existence of the in-phase and out-of phase super-modes. The obtained directivities and efficiencies are 9.34 dBi (7.01 dBi) and 96.82% (9.66%) for TMLR (TMSR) super-mode, respectively, at 193.5 THz. Moreover, the horizontal and bidirectional radiation patterns are appropriate for on-chip wireless links with the quality factor of 69.18 and target tracking systems, respectively. The performance of a single row array of nano-antenna on improving the directivity and efficiency has been studied. The proposed SHPW-fed nano-antenna is quite tolerant to practical fabrication errors and compatible with lift-off and electron beam lithography fabrication processes.
Maryam Khodadadi, Najmeh Nozhat, and Seyyed Mohammad Mehdi Moshiri
Springer Science and Business Media LLC
AbstractIn this paper, a circular hybrid plasmonic waveguide-fed nano-antenna (CHPWFNA) has been introduced for operating at the standard telecommunication wavelength of 1,550 nm. For the first time, the dispersion relation of a circular hybrid plasmonic waveguide as the feed line of the proposed nano-antenna has been derived, analytically. To verify the accuracy of the analytical solution, two numerical techniques of finite element method (FEM) and finite-difference time-domain (FDTD) method have been used. Numerical results are well-matched with the theoretical ones. The characteristics of the CHPWFNA have been studied by two mentioned methods. The obtained realized gains (directivities) by the FDTD and FEM simulations are 9.03 dB (9.38 dBi) and 10.00 dB (10.32 dBi), respectively, at 1,550 nm wavelength. For on-chip point-to-point wireless link performance, the obtained quality factor by the FDTD method (FEM) is 63.97 (100). The obtained radiation characteristics and link performance reveal that at 1,550 nm, the proposed antenna has the best performance. Besides, the frequency bandwidth of the antenna (185–200 THz) covers the low-loss optical frequency range. Also, paying attention to the laser eye safety is so important. Consequently, the wavelength of 1,550 nm has been chosen as the target wavelength. Moreover, the array configuration has been studied and the directivity and realized gain have been obtained based on the array factor theory and numerical methods, which are agree with each other. The attained realized gain by the FDTD method (FEM) for the considered single row array, at 1,550 nm, is 11.20 dB (11.30 dB). There is a little difference between the numerical results due to the total mesh size, the grid size refinement and the relative error of the numerical methods convergence. Finally, as one of the most important challenges in fabrication is the gold surface quality, we have studied the effect of gold surface roughness and its pentagonal cross section on the antenna performance.
Maryam Khodadadi, Seyyed Mohammad Mehdi Moshiri, and Najmeh Nozhat
Institute of Electrical and Electronics Engineers (IEEE)
A simultaneous plasmonic refractive index and thickness bio-sensor has been investigated theoretically and numerically to detect DNA hybridization and biomolecules attached to the inner wall of nano-ring resonators. The finite element method has been used to better appreciate the derived transmission formula based on both transfer matrix and coupled mode theories. For the first time, by applying a monolayer of graphene around the nano-ring resonators and introducing a MIM circular coupled waveguide, the power coupling coefficient, figure of merit and efficiency of the bio-sensor have been enhanced. Also, the coupling distance and optical properties including the chemical potential of graphene have been considered and studied to obtain optimal results. The maximum attained sensitivity and figure of merit of the bio-sensor are 1100 nm/RIU and 200 RIU−1, respectively. By employing a strong coupling condition, the full-width at half-maximum and extinction ratio have been obtained as 5 nm and 40 dB, respectively. Finally, the potential of the proposed structure as simultaneous AND and NOR logic gates have been studied with the intensity contrast ratios of 57 and 102.6 dB, respectively. Due to the excellent performance of the graphene-based circular plasmonic structure, it can find significant applications in photonic integrated circuits and on-chip nano-sensors.
Seyyed Mohammad Mehdi Moshiri, Maryam Khodadadi, and Najmeh Nozhat
Optica Publishing Group
In this paper, an all-optical plasmonic multi-wavelength switch based on Kerr nonlinear material is proposed. It consists of circular waveguides wrapped around three side-coupled nano-ring resonators. Fundamentally, introducing the circular waveguide increases the coupling coefficient and switching modulation depth. The transmission response of the proposed multi-switching structure is studied theoretically based on coupled mode and transfer matrix theories. The validity of the derived transmission formula is confirmed by the numerical result obtained by the finite element method. Also, based on the self-phase modulation and cross-phase modulation (XPM) nonlinear effects, the resonance wavelengths are effortlessly tuned by changing the intensity of the incident lightwave without changing the dimensions of the structure. As a result, by utilizing the XPM effect, the required input signal intensity is significantly decreased to 6.5 M W / c m 2 . The obtained modulation depths are 18.08, 31.83, and 28.40 dB at wavelengths of 850, 1310, and 1550 nm, respectively. Finally, to show the application of the proposed switch, the simultaneous AND and NOR logic gates are designed with intensity contrast ratios of 78.81 and 85.49 dB, respectively. The proposed plasmonic switch has many advantages such as being multi-wavelength and having low required switching intensity, ultra-fast switching time of 23 fs, and optical bistability. These features are promising for future integrated plasmonic devices for applications such as communications, signal processing, and sensing.
Maryam Khodadadi, Najmeh Nozhat, and Seyyed Mohammad Mehdi Moshiri
IOP Publishing
In this paper, a wideband hybrid plasmonic V-shaped nano-antenna is proposed based on coupled hybrid plasmonic waveguide (CHPW) feeding to increase the surface plasmon propagation length. The CHPW specifications are investigated analytically and numerically to obtain the dispersion relation and propagation length using the genetic algorithm and the finite element method, respectively. Moreover, the proposed V-shaped nano-antenna, with a fractional bandwidth of ∼86% and a maximum efficiency of 98%, is able to receive/transmit optical signals at three telecommunication wavelengths of 850, 1310, and 1550 nm with high realized gains of 10.5, 9.39, and 9.05 dB, respectively. The shape of the radiation pattern, with a main lobe along the antenna axis, makes this antenna appropriate for point-to-point connections in inter- or intra-chip optical wireless links and networks, which is studied comprehensively in this article. Furthermore, to obtain a high optical power signal and tune the antenna orientation, the performance of the antenna is investigated with two different types of array structure, single row and square, and its applications for energy harvesting and beam steering are studied. The fabrication feasibility of the nano-antenna is realizable based on complementary metal-oxide-semiconductor technology.
Maryam Khodadadi, Najmeh Nozhat, and Seyyed Mohammad Mehdi Moshiri
Optica Publishing Group
In this paper, a wideband InP-based hybrid plasmonic nano-antenna (HPNA) operating at telecommunication wavelengths has been proposed. Monolithically integrating InP-based lasers with hybrid plasmonic waveguide (HPW) as a feed line of the proposed HPNA on the same InGaAsP/InP wafer can increase the antenna efficiency. A new vertical director has been employed to have a highly directive horizontal radiation pattern. This enhancement is attributed to the efficient coupling between the radiation patterns of arm elements as well as reduced side lobes and back-lobes levels due to the achieved impedance matching. As a result, the directivity has been increased considerably, 3.6 dBi at 193.5 THz (1550 nm) and 1.1 dBi at 229 THz (1310 nm). The HPNA shows the high directivity, total efficiency and quality factor of 11.8, 97.49% and 94.57, respectively. Further, to verify the validity of confining the fundamental TM mode to a thin layer with the lower refractive index, both theoretical and numerical methods have been employed. Therefore, we have derived an analytical formula to investigate the HPW dispersion relation based on the transfer matrix theory and genetic algorithm. Moreover, due to the HPNA ability to receive an optical signal from free space and transmit it to the waveguide based on the reciprocity theorem, the HPNA performance as an optical wireless on-chip nano-link has been investigated analytically and numerically. Additionally, to obtain a high optical power signal and steering the beam angle, the antenna gain and directivity have been calculated with two different types of array structure by controlling the relative phase shift between the array elements and elements number. To validate the array design performance, a three dimensional full-wave numerical simulation and array factor theory have been exploited. The HPNA fabrication is compatible with generic foundry technology.
Seyyed Mohammad Mehdi Moshiri, Maryam Khodadadi, and Najmeh Nozhat
Elsevier BV
Zahra Mohebbi, Najmeh Nozhat, and Maryam Khodadadi
Informa UK Limited
ABSTRACT In this paper, we have proposed AND and XOR logic gates simultaneously in one structure. The presented structure is based on two-dimensional (2D) nonlinear photonic crystal with T–shaped waveguide and micro-ring resonator. In the proposed structure, the power consumption is that is lower than similar logic gates and the extinction ratio is about 6.5 dB. Also, the switching time is attained to be 0.2 and 0.26 ps for AND and XOR logic gates, respectively. Simplicity and small size (18.4 µm×18.4 µm) of the structure make it suitable for photonic integrated circuits (PICs). All simulations are based on finite-difference time-domain (FDTD) and plane wave expansion (PWE) numerical methods.
Najmeh Nozhat, Hamid Alikomak, and Maryam Khodadadi
Elsevier BV