Advanced Electromagnetics

Design and Modeling of a Photonic Crystal Multiplexer Using Artificial Intelligence

Wed, 16 Apr 2025 00:00:00 +0200

In this paper, design and modeling of an all-optical 2×1 multiplexer based on 2D photonic crystals and artificial neural networks (ANNs) are presented. The proposed structure aims to maximize the difference between the output powers in logical states, which is critical for enhancing the system ability to distinguish between these states. In this study, an ANN model is employed to accurately predict the normalized output power of the designed photonic crystal multiplexer, providing a time-efficient alternative to conventional simulation methods for analyzing multiplexer behavior across various logical states. The results demonstrate significant improvements in signal separation and overall performance compared to previous works. Additionally, a detailed comparison of the normalized output power for different logic states is provided, highlighting the advantages of the proposed design.

A Miniature Hexa-Band Antenna for Internet of Things Applications Using Six Quarter-wavelength Resonators

Y. M. Hasan, Z.-A. S. A. Rahman, Y. Al-Yasir — Wed, 16 Apr 2025 00:00:00 +0200

This work presents a compact, low-cost hexa-band microstrip antenna for Internet of Things (IoT) applications. The proposed hexa-band antenna is composed of simple six-λ/4 resonators to generate six resonant frequencies: GSM 1.84 GHz (1.8 –1.89 GHz), Bluetooth 2.31 GHz (2.25 –2.375 GHz), WiMAX 3.3 GHz (3.16 –3.47 GHz), WiFi 4.63 GHz (4.34 –5 GHz), upper WLAN 6.1 GHz (5.8 –6.91 GHz), and X-band 9.26 GHz (8.87 –9.83 GHz). The proposed hexa-band antenna is fabricated using FR4 substrate with (23 × 20 × 1.6) mm3 dimensions, and its measured results are presented to validate the simulated results. Results from simulations and measurements are used to examine the radiation properties, including radiation patterns, gain, efficiency, VSWR, and reflection coefficient. The proposed hexa-band antenna has a miniaturized size and good radiation performance.

A Super-Wideband Miniaturized Graphene-Based Folded Monopole Antenna

L. Guo — Sat, 15 Feb 2025 00:00:00 +0100

A graphene-based folded monopole antenna with super-wideband bandwidth and a small volume is proposed in this paper. The antenna features a disc-loaded folded cylindrical configuration that mainly consists of graphene-powder and graphene-ink cylinders, along with copper discs. Two primary radiation modes are generated and combined to achieve the desired super-wideband bandwidth. The applied graphene-powder and graphene-ink cylinders serve as crucial radiating and tunable elements, rendering the antenna impedance matched across the super-wideband range. Furthermore, direct current (DC) excitation combined with conducting wires is utilized to improve impedance matching and enhance the operating bandwidth toward lower frequencies. The measured results indicate that the antenna has a super-wideband operating bandwidth across 0.114-0.202 GHz and 0.34-18 GHz (|S11| <-6 dB). The measured antenna peak gains range from -3.75-3.50 dBi. The antenna dimensions can be maintained at 0.006λL ×0.006λL × 0.011λL, where λL is the wavelength in free space at the lowest operating frequency.

Polarization-independent wideband meta-material rasorber with wide transmission window based on resistor loaded circular and split ring resonators

A. Kumar, G. Sen, J. Ghosh — Thu, 20 Feb 2025 00:00:00 +0100

A dual polarized with high absorption to right side and wide in-band transmission is proposed in this study. Our proposed design consists of four modified split ring resonators on the top layer and four lumped resistor of 150 Ω value is connected between them to absorb the incoming EM wave in the out-ofband frequency regime.The circular slotted cut on the lower layer is responsible for in-band transmission. The lower layer is behaving as a ground plane for out-of-band absorption and and passing a range of frequency for the transmission band. So, bottom layer is behave as a band-pass frequency selective surface filter. The design has an overall thickness of 0.18λ and a fractional bandwidth of approximately 113%. The entire design exhibits an insertion loss of 1.10 dB at the transmission band at around 5.93 GHz and exceeding 80% absorption from 2.8 GHz to 10.0 GHz. The proposed design is polarization insensitive due to its symmetrical design and angularly stable up to 45Åã for both both TE and TM polarization of wave. The novelty of the proposed design lies in its wide out-of-band absorption, wide in-band transmission, minimal thickness, high fractional bandwidth, good angular stability, cost-effectiveness, accessibility through the use of inexpensive materials for manufacture and simple design. To analyze the proposed rasorber, we have investigated the polarization behavior, surface current distribution and design other parameters. Lastly, the proposed structure has been constructed using PCB technology and validated in a semi-anechoic chamber. The simulated and measured responses exhibit a high degree of agreement.

Triple-Band Circular Ring Monopole Antenna for RF Power Harvesting Applications

J. M. Mebara Mbida, G. A. Eyebe, G. Singh, C. Mbinack, M. N. Yende — Tue, 15 Apr 2025 00:00:00 +0200

This paper presents a simple and efficient approach for an antenna design and construction based on an I-shaped slot-loaded triple wideband microstrip monopole antenna with novel radio frequency (RF) power/energy harvesting capability. The proposed antenna takes advantage of circular ring shape properties, loaded with an I-shaped slot with degraded ground structure (DGS) to improve the input performances of the conventional planar circular microstrip patch antenna (C-patch). Input impedance and magnetic field radiation pattern are calculated using the electromagnetic theory of transmission line in traveling waves and resonant cavity TE11 field mode, respectively. The proposed antenna is configured on thin lossy substrate material RO4003C of volume 64.800×57.000×1.524 (in mm3), relative dielectric permittivity εr = 3.55, and numerically investigated using CST MWS. The prototype of the proposed antenna has been fabricated and tested. The experimental results show that the fabricated antenna exhibits an impressive 142% (2.98-11.11 GHz), 21.3% (11.54-14.42 GHz), and 19.6% (15.78-19.44 GHz) fractional bandwidth (FBW) for the resonant frequency of 5.73, 13.55, and 18.69 GHz respectively and peak gain of 4.2 dBi at the frequency of 5.8 GHz. Experimentally, the proposed antenna can be used in multiple applications like 2.4 GHz (2.401-2.495 GHz) Wi-Fi band/5 GHz (5.170-5.875 GHz) WLAN band/(3.1-10.6 GHz) US UWB at the view of the achieved lower band, FR3 6G operation regarding the obtained middle/intermediate band, and the future wireless and millimeter-wave communication systems according to the obtained upper band.

In-House Design, Manufacturing, and Testing of a 2.856 GHz Combline Microwave Cavity Filter for the Low-Level RF Systems of Linear Particle Accelerators

Thu, 20 Feb 2025 00:00:00 +0100

A combline microwave cavity filter has been developed to generate the 2.856 GHz radio frequency (RF) tone to be used as the master reference of SPARC_LAB electron linac facility at the Frascati National Laboratories of the National Institute for Nuclear Physics (LNF-INFN). The filter must select the 36th harmonic from a frequency comb with a repetition frequency of 79.33MHz and reject the other harmonics. The comb is generated by the electric conversion of the laser pulse train from the oscillator of the photocathode laser. Since a filter for this very specific application is off-the-shelf, it was designed, manufactured, and tested in-house at LNF-INFN. The measured insertion loss at the center frequency is 2.2 dB, the bandwidth is 30MHz (percentage fractional bandwidth is 1.1 %). This narrow bandwidth is required to ensure effective rejection (insertion loss > 65 dB) of adjacent harmonics in the frequency comb, specifically at frequencies of 2.77633 GHz and 2.93533 GHz. The purpose of filtering is to ensure that the tone, distributed in the low-level RF system, remains clean and can be used to synchronize the most crucial machine subsystems, such as RF power units, accelerating cavities, diagnostic systems, and lasers.

Design and Performance Analysis of a Dual Band Patch Antenna and its MIMO Implementation for Wi-Fi, Radar, and V2X Applications

P. P. Singh, S. K. Sharma, N. Gupta — Thu, 19 Jun 2025 00:00:00 +0200

A dual-band 2-port Multiple Input Multiple Output (MIMO) antenna is designed and analyzed in this paper. The designed antenna resonates at two frequencies, 4.54 GHz and 5.8 GHz, with bandwidths of 340 and 360 MHz for each band, respectively. A low-cost FR-4 substrate with a dielectric constant of 4.4 and a thickness of 1.6 mm is used to simulate and fabricate the antenna. Total dimension of a single antenna element is 17 mm×22 mm×1.6 mm (0.25λ×0.32λ×0.024λ), and the MIMO configuration measures 45 mm×22 mm×1.6 mm (0.66λ×0.32λ×0.024λ) at 3.6 GHz. The fundamental parameters of MIMO antenna like isolation (>20dB), ECC (<0.00012), DG (~10), MEG (-3dB), CCL (<0.2 bps/Hz) and TARC (<0.3) and radiation parameters are evaluated which prove the practicality of the antenna for Wi-Fi (5.725-5.85 GHz), 5G applications in Japan (4.4-4.5 GHz), radar (civilian and military), amateur radio communications (5.65-5.925 GHz), and Vehicle-to-Everything (V2X) (5.85-5.925 GHz) communication systems. Also, the designed antenna demonstrates radiation efficiency of more than 69% across first operating band and more than 76% across second operating frequency. The designed antenna can also be used in remote sensing applications to study various environmental parameters at 4.54 GHz, as electromagnetic waves at this frequency penetrate easily and provide data on soil moisture, vegetation, etc.

Dipole nanoantennas of single-walled carbon nanotube bundles: A numerical analysis

A. Salazar, F. R. Pérez, A. Ospina-Sanjuan — Mon, 21 Apr 2025 00:00:00 +0200

Carbon nanotube-based nanoantennas could configure important components in devices for applications in various fields, such as sensing, imaging, and signal transmission at the nanoscale. One of the factors that can affect the properties and, therefore, the performance of the nanoantenna is the temperature. In this work, the resonance properties at different temperatures for dipole nanoantennas formed from bundles of densely packed carbon nanotubes are analyzed. Calculations are made from the Hallén equation using the dynamic quantum conductivity and an equivalent radius for the antenna based on the surface area of the bundle. Results are obtained in the range from 1 GHz to1000 GHz and temperatures from 200K to 500K. A detailed calculation of the relaxation frequency is performed to consider the possible interaction of electrons with defects and acoustic and optical phonons. Input impedance, first resonance frequency, and radiation efficiency are obtained for different numbers of nanotubes in the bundle. Results show a significant effect of the temperature and surface area of the bundle on these parameters.

Enhancing Plasma Density through Periodic Dielectric Grating Structures-Numerical Simulations

D. Kakulia, K. Tavzarashvili, I. Noselidze, G. Kajaia — Sat, 24 Aug 2024 00:00:00 +0200

This paper proposes an idea of the use of Dielectric Resonators (DRs) as concentrators of alternating magnetic fields for plasma density control applications. The study involves numerical simulations using the Method of Auxiliary Sources (MAS) to analyze Dielectric Frequency Selective Surfaces (DFSS) composed of periodic dielectric elements. Materials with variable dielectric permittivities, including E-Glass, Plexiglass, Taconic CER-10, and Teflon are considered, and their resonance properties are investigated. Results indicate that DFSSs can create strong magnetic fields at resonance frequencies, which can be utilized for plasma density regulation in processes like thin film deposition. The results demonstrate that materials with lower dielectric permittivity, such as Plexiglass and Teflon, exhibit higher resonance quality factors, while higher permittivity materials like E-Glass and Taconic CER-10 show poorer quality factors. The study emphasizes the potential of DFSSs in enhancing plasma density and improving industrial applications, highlighting the importance of precise geometric configurations and material properties in designing effective dielectric resonators.

A compact four-element electromagnetic band gap and slots-inspired ultra-wideband multiple-input-multiple-output antenna with quad-band rejection characteristics

R. Kumari, V. K. Tomar — Tue, 13 May 2025 00:00:00 +0200

In this research, a four-element multiple-input-multiple-output (MIMO) antenna with ultra-wideband (UWB) operating range and quad-notch characteristics at WLAN (4.7-5.9 GHz), X-band uplink and downlink satellite systems (6.6-8.1 GHz), X-band NATO type-2 spectrum (8.6-10.96 GHz), and Ku-band fixed satellite services (FSS) and direct broadcast satellite (DBS) services (11.6-12.9 GHz) is designed on the FR-4 substrate of dimensions of 0.28λ0 × 0.32λ0 × 0.01λ0 (28 mm × 36 mm × 1 mm). In order to attain inter-element isolation of more than 20 dB, a pair of inverse-L stubs is introduced in the common ground plane of the proposed antenna. Additionally, good radiation characteristics with a maximum gain of 5.6 dBi and diversity parameters have been analyzed with envelope correlation coefficient (ECC < 0.001), diversity gain (DG > 9.5 dB), mean effective gain (MEG ≤ -3 dB), and total active reflection coefficient (TARC < -10 dB). The measured and simulated results of the proposed MIMO antenna, operating from 3.1 to 15.2 GHz, validate that it is a good choice for wireless communication applications.