In this paper, a dual-band eight-element MIMO antenna is presented for mobile devices, which operates in the 5G NR band n77 (3.3-4.2GHz), n48 (3.55-3.7GHz), n78 (3.3-3.8GHz), and n104 (6.425-7.125GHz). The gap between the two bands n77 and n104 is quite high, which leaves no room for adjacent band interference scenarios. The single-element planar antenna, a combination of inverted L and inverted Z units, measures 18mm in length and 7mm in height, making it compact enough for use in slim mobile phone devices. Each antenna element resonates at 3.7GHz and 6.7GHz. The distances between the antenna elements have been adjusted in such a way as to achieve self-decoupling and show isolation between adjacent ports, being better than -17.3 dB. The -6 dB impedance bandwidth is observed to be 0.84GHz and 1.27GHz for 3.7GHz and 6.7GHz, respectively, which covers a large portion of the 5G bands. The lower band is covering the widely used n77 band, while the higher band covers the n104 band, which has been selected for future WiFi-6E/7 and Sub-6GHz 5G applications. To validate simulated results, the measured results from a fabricated prototype unit have also been provided along with the simulated results.

This article presents a design of a four-port MIMO antenna to support dual circular polarization (CP) for Sub-6 GHz and WiFi-6E bands while emphasizing polarization diversity. The MIMO antenna comprises four elements, two configured for left-hand circular polarization (LHCP) and the other two for right-hand circular polarization (RHCP). To achieve circular polarization in each antenna element, a stub-loaded microstrip feed line and a slotted ground plane featuring a rectangular slot and a triangular stub are utilized. The antenna design features a compact form factor with dimensions of (0.63 × 0.63 × 0.019) λ0. It exhibits an impedance bandwidth (S11 ≤ −10 dB) spanning 3.2–7.2 GHz (76.92

This paper presents, a THz wideband metamaterial absorber using combination of one circular and two hexagonal rings. The absorber is the composition of vanadium dioxide (VO2), silicon dioxide (SiO2) and gold (Au) layer. The resonators has been designed on the top layer i.e. on vanadium dioxide (VO2). The numerical analysis of the proposed THz metamaterial absorber is carried out using CST microwave studio (electromagnetic field simulation software). The numerical analysis shows, absorption exceeding 97

This paper presents a dual-band pentagon double-ring loaded patch antenna, demonstrating effective operation in two distinct millimeter wave (mm-Wave) bands 28/38 GHz with a bandwidth of 17.80% & 6.46%. The gain of the proposed antenna is 3.92/4.57 dBi with radiation efficiency greater than 92% over the entire band of operation. The antenna is designed with precision using Rogers RT5880 substrate with a thickness of 0.508 mm & a relative permittivity of 2.2. This design represents a simple design approach for creating a dual-band and compact planar antenna for millimeter-wave 5G communication.

Surface plasmon resonance (SPR) has gained attention as a promising method for effective label-free biosensing. Immunoglobulin (IgG) detection is very important to understand the past infection and immunity of any individual. Thus, this study aims to develop a SPR sensor with better sensitivity for detecting IgG. It emphasizes the utilization of a high-performance planar waveguide-based SPR sensor to detect IgG by analyzing a suitable sensor topology. The sensor configuration consists of five distinct layers: silver (Ag), silicon nitride ( Si_3N_4 ), black phosphorus (BP), an enzyme, and a sensing medium. Silver (Ag) stimulates surface plasmons, while Si3N4 and BP are utilized to enhance absorption capabilities and serve as the bio-molecular recognition element, respectively. The proposed sensor simulation employs the transfer matrix method and an angular interrogation scheme. To assess this proposed sensor’s impact, the sensing region is assessed while considering three layers: Ag, Ag-BP, and Ag–Si3N4. Initially, the thickness of the Ag layer is optimized by recording its transmittance and achieving a minimum transmittance of 0.0027 at a thickness of 50 nm. Subsequently, the performance parameters are assessed using four different structures with slight variations in the IgG samples. The results depict the maximum achieved sensitivities as follows: 192 ^∘ /RIU for conventional SPR, 203 ^∘ /RIU for BP-based SPR, 287 ^∘ /RIU for Si3N4-based SPR, and 352 ^∘ /RIU for the proposed structure. This comparative study demonstrates that the proposed SPR configuration significantly enhances sensitivity, quality factor, and detection accuracy performance.

This work proposes a novel metamaterial perfect absorber (MPA) for the terahertz (THz) frequency range. The MPA utilizes a split-ring star-shaped pattern fabricated from vanadium dioxide (VO2) on a silicon dioxide (SiO2) dielectric substrate. The CST Microwave Studio is used for structure's absorption performance. The design employs a sub-wavelength unit cell to create a near-infinite periodic array. Numerical analysis of unit cell's shows absorption of 99.79% at a specific frequency of 4.108 THz. Furthermore, the MPA demonstrates a broad terahertz absorption bandwidth exceeding 90% ranging from 3.541 THz to 4.773 THz, which translates to a bandwidth of 1.232 THz.

This paper presents a novel design of second-order triple band waveguide bandpass filter using planar insert technology. A conventional WR-90 rectangular waveguide has two identical inserts inserted into its transverse plane at an optimal spacing of 8.41mm. The insert consists of a combination of a double-split square resonator and a single split square resonator with stub. These resonators are used to achieve triple-band bandpass characteristics. The structure allows independent control of three center frequencies, insertion loss, return loss and 3-dB bandwidth. The simulation analysis of the proposed filter is carried out using the CST microwave studio, and its frequency response is compared with its equivalent circuit response. To validate the numerical analysis, the WR-90 waveguide and planar insert are fabricated independently and inserted manually. The dual-pole triple band bandpass characteristic of the manufactured filter, with center frequencies of 8.19, 9.39 and 11.09GHz, is shown by the measured data. The complete design process has also been provided, along with a corresponding circuit diagram. The suggested waveguide filter's performance is evaluated against those found in the literature already.

This paper presents, a novel second order E-plane planar insert based dual band bandstop waveguide filter. The circular shape with two T-shape resonators are printed on Roger RO4350 dielectric substrate to form planar insert. The insert are placed in such a way that positioned in E-plane of the standard WR-90 rectangular waveguide. The independent resonant frequency and bandwidth of the stopband can be adjusted by tuning the resonators. To achieve second order dual band bandstop filter response four asymmetrical circular shape with two T-shape resonators are designed on dielectric substrate to form different stopbands and separated by some specific distance to eliminate the unwanted coupling between them. The numerical analysis of the proposed filter is carried out using CST microwave studio. To validate the numerical analysis of the proposed filter, resonator, WR-90 rectangular waveguide is fabricated and measured. The measured results shows stopband characteristics having centre frequencies f01g = 8.56 GHz and f02 = 11.21 GHz and exhibits the bandwidth of 0.4146 GHz and 0.3824 GHz. The simulated and measured result are in good agreement.

In this paper, a PIN diode is employed for frequency reconfiguration. An antenna is operating between 2.57 - 3.52 GHz and 4.89 - 6.18 GHz, it suits Wi-MAX (3.3 GHz), WLAN (5030 - 5990 MHz), and n46 (5150 - 5925 MHz) 5G bands when the diode is ON, and WLAN/n46 bands when OFF. The antenna achieves over 85% radiation efficiency and favorable gain, establishing it as a strong contender for 5G/WLAN/Wi-MAX applications.

In this paper, a PIN diode is employed for frequency reconfiguration. An antenna is operating between 2.57 - 3.52 GHz and 4.89 - 6.18 GHz, it suits Wi-MAX (3.3 GHz), WLAN (5030 - 5990 MHz), and n46 (5150 - 5925 MHz) 5G bands when the diode is ON, and WLAN/n46 bands when OFF. The antenna achieves over 85% radiation efficiency and favorable gain, establishing it as a strong contender for 5G/WLAN/Wi-MAX applications.

In this manuscript, a compact MIMO antenna for wireless application has been presented. The proposed antenna consists of the F-shaped radiator with the circular slot in the center and a rectangular ground plane on the other side of the substrate. The proposed antenna has the overall size of 48 ? 48 mm2. The antenna is designed to work on two frequency bands - from 1.5 to 2.3 GHz, and 3.7 to 4.2 GHz, having the resonating frequency of 1.8 GHz and 3.9 GHz respectively. The diversity performance of the antenna is also observed by using a variety of parameters like envelop correlation coefficient (ECC), Diversity Gain (DG), Total Active Reflection Coefficient (TARC), etc. The value of ECC is 0.02, which shows good diversity performance of the antenna. In order to validate the simulated and measured results, the proposed antenna has been fabricated and shows good agreement with the each other.

This paper presents a light weight second order triple band waveguide band pass filter using planar insert technology. To achieve second order filter characteristics two identical planar insert in which resonators has been designed is inserted into the transverse plane of WR-90 rectangular waveguide at a distance of 8.41mm. The numerical analysis has been done using CST microwave studio, which shows center frequencies of 8.89/ 9.87/ 11.37 GHz, 3-dB bandwidth is 0.32/0.367/0.48GHz and insertion loss of 0.9/0.9/0.7dB respectively.

The design of a Dielectric Resonator Antenna (DRA) utilizing machine learning approaches is presented in this study.Antennas are an essential part of a wireless network.An antenna with a decent design will reduce system requirements and improve overall system performance.Full-wave electromagnetic simulation is exact and necessary in antenna design.Still, it takes more time to perform, resulting in enormous challenges in designing, optimizing, and performing sensitivity analysis.The data in this study is subjected to several Machine Learning (ML) algorithms for optimizing antenna efficiency and S-parameter value.To expedite antenna design, machine learning-assisted optimization (MLAO) has proven to be the most effective method.A wide range of regression techniques, including as Support Vector Machine (SVM), Decision Tree Regression (DTR), and Random Forest Regression (RFR), have been used in machine learning (ML) techniques to develop antenna models, enabling quick response prediction and optimum S11 value.Multiple MLAO algorithms have been implemented using these machine-learning techniques for various applications out of which Decision Tree Regression and Random Forest Regression outperforms among all the above-mentioned algorithms with 99.98% and 99.99% of accuracy.First, a broad overview of recent advancements in ML approaches for antenna modelling is presented.

This paper presents a compact multiple-inputs multiple-outputs (MIMO) antenna for wireless local area network (WLAN) applications. The proposed four-port MIMO antenna has been incorporated with its four identical elements having dimensions of 10[Formula: see text]mm [Formula: see text] 12[Formula: see text]mm each. The MIMO antenna is designed to operate in the range of 5.17–6.25[Formula: see text]GHz frequency band having impedance bandwidth of 18.91%. The antenna is fabricated on a glass epoxy FR-4 substrate having a thickness of 0.8[Formula: see text]mm for measurement and validation. The measured results show that the antenna has good isolation greater than [Formula: see text]17[Formula: see text]dB to [Formula: see text]25[Formula: see text]dB, better impedance matching and envelope correlation coefficient (ECC) below 0.03 over the entire band of operation. The proposed MIMO antenna is a potential candidate for WLAN applications.

In this article, compact inverted F-antennas (IFAs) operating in the 3.5 GHz band is proposed for future 5G smartphone applications. The conventional IFA is modified to make the structure compact and efficient. The additional IFAs are aligned in face-to-face configuration to reduce the coupling between them up to some extent. Furthermore, a novel decoupling element is incorporated between antenna pairs to effectively enhance the isolation. As a result, the proposed building block exhibits isolation higher than 28.2 dB between two adjacent ports. Based on highly isolated building blocks, a 4 x 4 and 8 x 8 multi-input multi-output (MIMO) antenna array is designed and investigated which is operated in 3.5 GHz (LTE band 42). The proposed 8 x 8 MIMO antenna array has four compact building blocks and reserves sufficient space for integrating other antennas such as 2G/3G/4G antennas. To validate the simulated results, a prototype of the proposed antenna is fabricated and tested. Over the entire operating frequency, the fabricated 8 x 8 MIMO antenna array obtain high isolation of more than 27.3 dB, and high antenna efficiency (>61%). Also, its corresponding measured envelope correlation coefficients are lower than 0.04 and channel capacity was about 39.1-40.6 bps/Hz. The measured results show that the proposed MIMO antenna array is a good candidate for future fifth-generation smartphone applications.

An ultra-wideband, compact planar antenna with defected ground structure (DGS) has been presented in this article for future 5G millimeter-wave applications. The proposed antenna overcomes the limitation of bandwidth of the conventional microstrip patch antenna (typically < 5%). The antenna exhibits an ultra-wideband characteristic covering frequency band from 21.3 GHz to 40.6 GHz which makes the fractional bandwidth of 62.36%. The antenna performance is enhanced by etching slots on the patch and incorporating defect on the ground plane. The antenna achieves gain greater than 4.01 dBi and radiation efficiency greater than 95% throughout the operating band. In the given band it also exhibits very low cross-polarization level as well as stable radiation performance. This antenna is designed to operate in n257, n258, n260 and n261 5G millimeter-wave spectrum.

A combination of lowpass and dual band bandpass filter with improved selectivity is presented in this manuscript. Two circular split ring resonators which are connected at the upper side, provide a lowpass filter characteristics. In order to achieve combined lowpass with dual passband response two L-shape stubs are incorporated into the lowpass filter structure. The parametric analysis of the proposed filter has been carried out using CST microwave studio. The numerical result shows a 3-dB cutoff frequency for lowpass at 1.22 GHz, first and second passband resonant frequencies are 2.44 GHz and 3.7 GHz respectively. The proposed filter is compact and overall size of the proposed filter is 32.9 mm?15mm.