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Öğe Compact 5 G mmWave vivaldi antenna for vehicular communication(Elsevier Inc., 2025) Saleh, Sahar; Saeidi, Tale; Timmons, Nick; Althuwayb, Ayman A.; Razzaz, FaroqAs a key contribution, this article presents the first successful application of the newly developed Vivaldi Non-uniform Profile Antenna (VNSPA) theory to a Vivaldi Tapered Slot Antenna (VTSA) operating in the 26 GHz band (24.25–27.5 GHz). The proposed design achieves both compactness and simplicity while maintaining high performance. This antenna is a promising candidate for vehicular communication applications, aiming to enhance connectivity, road safety, security, and environmental system control. First, a VTSA with a small volume of 8.1 × 8.3 × 0.813 mm3 is designed, fabricated, and tested, providing S11 value < -11.34 dB at 15.96–28.41 GHz and a maximum realized gain of 6 dBi. Second, a 33 % size reduction of its tapered slot profile (TSP) is obtained by applying the VNSPA theory, resulting in the Vivaldi Non-uniform Slot Antenna (VNSA). Based on this theory, two different non-uniform slot profiles (NSPs) are obtained for VNSA 1 and 2 with final 37 % and 32.55 % volume reduction, respectively, based on parametric studies. VNSA 1 and 2 provide S11 values < -11.6 dB and < -14.3 dB at 16.71 to 27.68 GHz and 17.94 to 27.38 GHz with peak realized gains of 4.6 dBi and 5.15 dBi, respectively. Another key contribution of this research is the on-vehicle analysis of the proposed antenna's applicability for communication. This includes testing the antenna in various positions and demonstrating its capability to radiate in multiple directions, enabling effective communication with other vehicles, pedestrians, roadside units, and mobile networks. Another significant aspect of this research is the calculation of specific absorption rate (SAR), which addresses the effects of electromagnetic radiation on the driver, one back-seat passenger, and pedestrians. The Computer Simulation Technology (CST) software is used to carry out the simulation. © 2025Öğe A Deep Analysis of CPW-fed Planar Antennas for Frequencies 2.6 Up to 13.6 GHz(Wydawnictwo Sigma-Not Sp Zoo, 2023) Al-Gburi, Ahmed Jamal Abdullah; Zakaria, Zahriladha; Ibrahim, Imran Mohd; Khabba, Asma; Al-Obaidi, Aymen Dheyaa Khaleel; Saeidi, Tale; Paul, Liton ChandraThis paper presents a deep analysis of coplanar waveguide (CPW) feed Planar antenna for frequencies from 2.6 GHz up to 13.6 GHz, which covers the authorised Ultra-wideband (UWB) from 3.1-10.6GHz and the X-band from 8-12GHz applications. The Parametric analysis will help the researchers understand antenna parameters' effects on the reflection coefficient (S11) variations. These important parameters are the length of the CPW fed (Cl), the width of the substrate (W), the width of the feed-line (Wf) and the gap between the feed-line and CPW disk (g). The total physical planar antenna dimension is 26 mm x 26mm x 1.6 mm, corresponding to the centre frequency range at 7.5 GHz. The UWB CPW planar antenna is fed via a coplanar waveguide (CPW) to attain the best impedance matching for UWB systems. The presented CPW planar antenna has an impedance UWB bandwidth of 11.0 GHz from 2.6 GHz up to 13.6 GHz at -10 dB return loss. The simulated UWB planar antenna displays an omnidirectional radiation behaviour with a simulated gain of 7.3 dB at 13.6 GHz, a directivity of 7.5 dBi at 13.6 GHz and favourable radiation efficiency of 97%. The presented antenna has the specialised prospect to be used for UWB and X-band systems.Öğe Enhancing connectivity/mobility in WBAN applications through detachable wearable multi-band MIMO antenna(Institute of Physics, 2024) Saeidi, Tale; Saleh, Sahar; Timmons, Nick; Karamzadeh, Saeid; Al-Gburi, Ahmed Jamal Abdullah; Razzaz, FaroqThe connectivity and mobility of a miniaturized multi-band four-port textile leaky wave multiple-input multiple-output (MIMO) antenna designed on a layer of denim (ϵr = 1.6, tanδ = 0.006) is enhanced by integrating it with two detachable spiral buttons designed on circular PTFE substrate (ϵr = 2.1, tanδ = 0.001). The connectivity and mobility enhancement of the proposed antenna is evaluated in terms of radiation and diversity parameters. Nested hexagonal split rings behind the buttons, U-shaped slots on textiles, a comb-shaped neutralization network, and an aperture-coupled feed technique are utilized. The unique structure of the buttons on a rigid substrate and the leaky wave antenna on the textile and their integration, the periodic nested elliptical and circular split ring resonators (CSRRs) slots on the aperture coupled to ground, are to expand the connectivity and mobility of the proposed MIMO antenna by offering multiple bands, higher isolation, broadside radiation, and low specific absorption rate (SAR). The leaky wave and button antennas have dimensions of 40 × 30 × 1 mm3 and a diameter of only 13 mm, respectively. The operational bands are 0.86-2.75 GHz, 2.9-4.85 GHz, 5.75-6.15 GHz, and 8-9.85 GHz, covering the L, C, S, and X bands. Additionally, diversity performance is evaluated by defining the envelope correlation coefficient (ECC), diversity gain (DG), Channel Capacity Loss (CCL), and mean effective gain (MEG). The simulation and measurement findings are in good agreement. Following that, it offers a maximum gain of 8.25 dBi, low SAR (<0.05), an ECC below 0.05, DG above 9.85 dB, CCL< 0.25 bits/s/Hz, MEG <−3 dB, Circular polarization (CP), and strong isolation (>22 dB) between every two ports. These features make the proposed antenna an ideal option for MIMO communications and suitable for wireless local area network (WLAN) and fifth-generation (5G) communications. © 2024 IOP Publishing Ltd.Öğe Enhancing connectivity/mobility in WBAN applications through detachable wearable multi-band MIMO antenna(IOP publishing, 2024) Saeidi, Tale; Saleh, Sahar; Timmons, Nick; Karamzadeh, Saeid; Al-Gburi, Ahmed Jamal Abdullah; Razzaz, FaroqThe connectivity and mobility of a miniaturized multi-band four-port textile leaky wave multiple-input multiple-output (MIMO) antenna designed on a layer of denim (epsilon(r) = 1.6, tan delta = 0.006) is enhanced by integrating it with two detachable spiral buttons designed on circular PTFE substrate (epsilon(r) = 2.1, tan delta = 0.001). The connectivity and mobility enhancement of the proposed antenna is evaluated in terms of radiation and diversity parameters. Nested hexagonal split rings behind the buttons, U-shaped slots on textiles, a comb-shaped neutralization network, and an aperture-coupled feed technique are utilized. The unique structure of the buttons on a rigid substrate and the leaky wave antenna on the textile and their integration, the periodic nested elliptical and circular split ring resonators (CSRRs) slots on the aperture coupled to ground, are to expand the connectivity and mobility of the proposed MIMO antenna by offering multiple bands, higher isolation, broadside radiation, and low specific absorption rate (SAR). The leaky wave and button antennas have dimensions of 40 x 30 x 1 mm(3) and a diameter of only 13 mm, respectively. The operational bands are 0.86-2.75 GHz, 2.9-4.85 GHz, 5.75-6.15 GHz, and 8-9.85 GHz, covering the L, C, S, and X bands. Additionally, diversity performance is evaluated by defining the envelope correlation coefficient (ECC), diversity gain (DG), Channel Capacity Loss (CCL), and mean effective gain (MEG). The simulation and measurement findings are in good agreement. Following that, it offers a maximum gain of 8.25 dBi, low SAR (<0.05), an ECC below 0.05, DG above 9.85 dB, CCL< 0.25 bits/s/Hz, MEG <-3 dB, Circular polarization (CP), and strong isolation (>22 dB) between every two ports. These features make the proposed antenna an ideal option for MIMO communications and suitable for wireless local area network (WLAN) and fifth-generation (5G) communications.Öğe Health Control of Tree Trunk Utilizing Microwave Imaging and Reverse Problem Algorithms(Amer Chemical Soc, 2023) Alhawari, Adam R. H.; Saeidi, Tale; Ismail, Idris; Alsuwian, Turki; Al-Gburi, Ahmed Jamal AbdullahThe voids in their trunk significantly affect tropical trees' health. Both the wood and timber industries may face substantial financial losses because of the lack of an effective technique to inspect the defected trees through deep zonal monitoring. Microwave imaging offers the advantages of mobility, processing time, compactness, and resolution over alternative imaging methods. An ultra-wide band (UWB) imaging system consisting of UWB antennas and a reverse problem algorithm is proposed. Several conditions, such as the size of trunk samples (16-30 cm), number of targets, size of voids, heterogeneity of media, and number of layers, are considered in experimental studies. Based on these studies, cylindrical wooden models with 100 and 140 mm diameters, one void at the center, and three voids in different locations were 3D printed. After proving the system's ability through simulation and measurements on 3D models, a rubber-wood trunk with a length of 75 cm was cut into smaller pieces. The images created utilizing the measured data showed that the system could detect voids in the rubber trunk. Furthermore, the system indicated a high percentage of reliability and repeatability.Öğe High gain couple feed multiband wearable antenna for 5g and sub-6 GHz communications(WILEY, 2022) Saeidi, Tale; Karamzadeh, SaeidA multi-band, small, high gain, low specific absorption rate (SAR), and circularly polarized (CP) textile wearable antenna fed using aperture coupled technique is designed on two layers of denim (epsilon r=1.2$$ {\boldsymbol{\varepsilon}}_{\boldsymbol{r}}=\mathbf{1.2} $$, h = 0.787 mm as feeding layer) and felt (epsilon r=1.3$$ {\boldsymbol{\varepsilon}}_{\boldsymbol{r}}=\mathbf{1.3} $$, h = 1.5 mm as a resonating layer) textile substrates. The antenna is designed on two layers with two relative permittivities to enhance the BW and reduce the negative mutual coupling. Afterward, another layer of denim with the complete ground of ShieldIt conductor is added to decrease the SAR value along with the directive gain. The antenna works for Industrial, Scientific, and Medical (ISM), 5G, and sub-6 GHz communication systems as it operates at 2.45-2.55 GHz and 3.8 GHz (3.6-4.15 GHz), and 5.6 GHz (5.55-5.65 GHz), respectively. The proposed antenna has the maximum directive gain of 8.35 dBi, acceptable SAR values at a 10 mm distance from the human body for both standards. In addition, the antenna's CP is examined, showing AR values of <2.5 dB at the working BW. Finally, the proposed antenna is measured and compared with the simulation results. A good agreement exists between simulation and measurement results.Öğe High gain multi-band circularly polarized wearable leaky wave zipper MIMO antenna(Cell press, 2024) Saeidi, Tale; Saleh, Sahar; Mahmood, Sarmad Nozad; Timmons, Nick; Al-Gburi, Ahmed Jamal Abdullah; Karamzadeh, Saeid; Razzaz, FaroqA miniaturized, multi-band, four-port wearable Multiple Input Multiple Output (MIMO) antenna is proposed, which contains a leaky wave textile antenna (LWTA) on denim (epsilon(r) = 1.6, tan delta = 0.006) as substrate and Shieldit Super Fabric as conductor textile. The concept in this work involves incorporating the metal and plastic zipper into the garment to function as an antenna worn on the body. Simulations and measurements have been conducted to explore this idea. The LWTA has dimensions of 40 x 30 x 1 mm(3). Every two ports are separated by a zipper with two different kinds of materials: Acetal Polymer Plastic (APP) and 90 % brass to improve the isolation, gain, and Impedance bandwidth. The antenna operates in the frequency ranges covering the L, C, S, and X bands. Additionally, diversity performance is evaluated using the Envelope Correlation Coefficient (ECC) and diversity gain (DG). Simulation and measurement findings agree well, with a maximum gain of 12.15 dBi, low Specific Absorption Rate (SAR) based on the standards, DG greater than 9.65 dB, circular polarization (CP), and strong isolation (<-23 dB) between each port. Since the antenna's characteristics do not change significantly under bending and when the zipper is opened, the proposed antenna is a viable candidate for body-centric wireless communications on the battlefield. For example, it can facilitate communication covering wireless local area network (WLAN) and fifth-generation (5G) communications.Öğe High gain wide band flexible leaky wave MIMO antenna for AIP applications(IEEE, 2022) Saeidi, Tale; Karamzadeh, SaeidA four-port flexible Leaky Wave Antenna (LWA) is designed in the D-band to obtain a pencil beam radiation pattern with consistent gain and miniaturized size for Antenna in Package (AiP) applications. It is designed on a polyimide substrate with dielectric constant of 3.5, tangent loss of 0.006, and thickness of 10 mu m. It consists of two rectangular patches fed through the Coplanar Waveguide (CPW) feeding technique. It also combines transverse and longitudinal slots on the rectangular patches to create circular polarization and improve the open stop-band issue of the LWAs. In addition, a matching element is utilized at each feeding, and then the feed line is cut by H-slots to improve the mutual coupling of the antenna. The proposed antenna offers a wide Bandwidth (BW) of 110- 135 GHz with small dimensions of 6 x 7 mm(2). The main beam scans from -87 degrees at 110 GHz to 0 degrees at 130 GHz. The simulated peak gain of 14.8 dBic is obtained in an almost broadside direction at 115 GHz.Öğe High-performance UWB Vivaldi antenna on FR4: A cost-effective solution for wearable technologies(Elsevier B.V., 2025) Saleh, Sahar; Saeidi, Tale; Timmons, Nick; Alali, Bader; Razzaz, Faroq; Althuwayb, Ayman A.This paper introduces a novel Vivaldi Tapered Slot Antenna (VTSA) designed for wearable Ultra-Wideband (UWB) applications, utilizing a cost-effective FR4 substrate with a thickness of 0.8 mm. The proposed design achieves an 18.81 % size reduction (38.3 mm × 27.06 mm × 0.8 mm), a 36.16 % bandwidth (BW) increase, and a 16.63 % gain improvement compared to a VTSA using a Rogers RO4003C substrate (42.9 mm × 28.28 mm × 0.813 mm). The key contributions of this work include the effective use of the affordable FR4 substrate to achieve high performance, improvements in antenna compactness and BW through innovative slot designs, and the enhancement of gain and radiation pattern stability through the addition of directors to the slots. These modifications significantly boost the antenna's performance while maintaining a compact design. The antenna's suitability for wearable applications was validated through testing on flat and curved human phantoms made of skin, fat, and muscle, showing low Specific Absorption Rate (SAR) values across the UWB spectrum, confirming its safety for body-centric use. Measured results include S11 values below -10.56 dB over the 3.66–20.42 GHz range, a peak gain of 8.1 dBi, stable radiation patterns, and an average group delay of 0.83 ns. Simulations using Computer Simulation Technology (CST) were validated by experimental testing, demonstrating the antenna's potential for wearable and body-centric applications. © 2025 The Author(s)Öğe Meta Surface-Based Multiband MIMO Antenna for UAV Communications at mm-Wave and Sub-THz Bands(Multidisciplinary Digital Publishing Institute (MDPI), 2024) Saeidi, Tale; Saleh, Sahar; Timmons, Nick; Al-Gburi, Ahmed Jamal Abdullah; Karamzadeh, Saeid; Althuwayb, Ayman A.; Rashid, Nasr; Kaaniche, Khaled; Ben Atitallah, Ahmed; Elhamrawy, Osama I.Unmanned aerial vehicles (UAVs) need high data rate connectivity, which is achievable through mm-waves and sub-THz bands. The proposed two-port leaky wave MIMO antenna, employing a coplanar proximity technique that combines capacitive and inductive loading, addresses this need. Featuring mesh-like slots and a vertical slot to mitigate open-stopband (OSB) issues, the antenna radiates broadside and bidirectionally. H-shaped slots on a strip enhance port isolation, and a coffee bean metasurface (MTS) boosts radiation efficiency and gain. Simulations and experiments considering various realistic scenarios, each at varying vertical and horizontal distances, show steered beam patterns, circular polarization (CP), and high-gain properties, with a maximum gain of 13.8 dBi, an axial ratio (AR) <2.9, a diversity gain (DG) >9.98 dB, and an envelope correlation coefficient (ECC) <0.003. This design supports drones-to-ground (D2G), drone-to-drone (D2D), and drone-to-satellite (D2S) communications. © 2024 by the authors.Öğe A Miniaturized and Highly Sensitive Microwave Sensor Based on CSRR for Characterization of Liquid Materials(Mdpi, 2023) Al-Gburi, Ahmed Jamal Abdullah; Zakaria, Zahriladha; Abd Rahman, Norhanani; Althuwayb, Ayman A.; Ibrahim, Imran Mohd; Saeidi, Tale; Dayo, Zaheer AhmedIn this work, a miniaturized and highly sensitive microwave sensor based on a complementary split-ring resonator (CSRR) is proposed for the detection of liquid materials. The modeled sensor was designed based on the CSRR structure with triple rings (TRs) and a curve feed for improved measurement sensitivity. The designed sensor oscillates at a single frequency of 2.5 GHz, which is simulated using an Ansys HFSS simulator. The electromagnetic simulation explains the basis of the mode resonance of all two-port resonators. Five variations of the liquid media under tests (MUTs) are simulated and measured. These liquid MUTs are as follows: without a sample (without a tube), air (empty tube), ethanol, methanol, and distilled water (DI). A detailed sensitivity calculation is performed for the resonance band at 2.5 GHz. The MUTs mechanism is performed with a polypropylene tube (PP). The samples of dielectric material are filled into PP tube channels and loaded into the CSRR center hole; the E-fields around the sensor affect the relationship with the liquid MUTs, resulting in a high Q-factor value. The final sensor has a Q-factor value and sensitivity of 520 and 7.032 (MHz)/e(r)) at 2.5 GHz, respectively. Due to the high sensitivity of the presented sensor for characterizing various liquid penetrations, the sensor is also of interest for accurate estimations of solute concentrations in liquid media. Finally, the relationship between the permittivity and Q-factor value at the resonant frequency is derived and investigated. These given results make the presented resonator ideal for the characterization of liquid materials.Öğe A Miniaturized Full-Ground Dual-Band MIMO Spiral Button Wearable Antenna for 5G and Sub-6 GHz Communications(Mdpi, 2023) Saeidi, Tale; Al-Gburi, Ahmed Jamal Abdullah; Karamzadeh, SaeidA detachable miniaturized three-element spirals radiator button antenna integrated with a compact leaky-wave wearable antenna forming a dual-band three-port antenna is proposed. The leaky-wave antenna is fabricated on a denim (epsilon(r) = 1.6, tan delta = 0.006) textile substrate with dimensions of 0.37 lambda(0) x 0.25 lambda(0) x 0.01 lambda(0) mm(3) and a detachable rigid button of 20 mm diameter (on a PTFE substrate epsilon(r) = 2.01, tan delta = 0.001). It augments users' comfort, making it one of the smallest to date in the literature. The designed antenna, with 3.25 to 3.65 GHz and 5.4 to 5.85 GHz operational bands, covers the wireless local area network (WLAN) frequency (5.1-5.5 GHz), the fifth-generation (5G) communication band. Low mutual coupling between the ports and the button antenna elements ensures high diversity performance. The performance of the specific absorption rate (SAR) and the envelope correlation coefficient (ECC) are also examined. The simulation and measurement findings agree well. Low SAR, <-0.05 of LCC, more than 9.5 dBi diversity gain, dual polarization, and strong isolation between every two ports all point to the proposed antenna being an ideal option for use as a MIMO antenna for communications.Öğe A Miniaturized Multi-Frequency Wide-Band Leaky Wave Button Antenna for ISM/5G Communications and WBAN Applications(Amer Geophysical Union, 2023) Saeidi, Tale; Karamzadeh, SaeidA low-profile multi-frequency leaky wave button antenna for body-centric communications is presented. A leaky wave antenna loaded with U-slots (a combination of U-slots and slits) and tapered slot structures to improve the radiation efficiency, broadside radiation pattern, and widen the steering range is designed. Furthermore, it comprises a whole ground to meet the Specific Absorption Rate standard requirements based on the known standards. The antenna's performances are examined for on and off-body conditions. For demonstration, a prototype is implemented, and the measurement is performed on the chest. The antenna operates at multi bands of 1.7-3.3 GHz (Industrial, Scientific, and Medical and 5G communication) and 4.15-10 GHz (sub-6 GHz and X-band communications). The peak gains of 6.9 and 8.2 dBi were obtained for on and off- body conditions, respectively. Furthermore, the antenna offers maximum radiation efficiencies of 89.3% and 99.3% for on-body and free-space conditions. The specific absorption rate (SAR) values obtained for body-centric communications meet the regulation requirements (e.g., on body tissue at 3.2 GHz, it is 0.78 (1 g) and 0.44 (10 g) W/kg). With an overall miniaturized size, the proposed button antenna could be integrated with clothes. In addition, a multi-wide bandwidth, circularly polarized radiation, a small size, high efficiency and gain, and low SAR values prove that the proposed antenna can be a potential candidate for wireless body area network and simultaneous wireless information and power transfer applications.Öğe Simple compact UWB vivaldi antenna arrays for breast cancer detection(MDPI, 2024) Saleh, Sahar; Saeidi, Tale; Timmons, NickIn this study, at ultra-wideband (UWB) frequency band (3.1-10.6 GHz), we propose the use of compact 2:1 and 3:1 nonuniform transmission line Wilkinson power dividers (NTL WPDs) as feeding networks for simple 2 x 1 linear UWB Vivaldi tapered and nonuniform slot antenna (VTSA and VNSA) arrays. The 2:1 and 3:1 tapered transmission line (TTL) WPDs are designed and tested in this work as benchmarks for NTL WPDs. The VTSA array provides measured S-11 < -10.28 dB at 2.42-11.52 GHz, with a maximum gain of 8.61 dBi, which is 24.39% higher than the single element. Using the VNSA array, we achieve 52% compactness and 6.76% bandwidth enhancement, with good measured results of S-11 < -10.2 dB at 3.24-13 GHz and 15.11% improved gain (8.14 dBi) compared to the VNSA single element. The findings show that the NTL and Vivaldi nonuniform slot profile antenna (VNSPA) theories are successful at reducing the size of the UWB WPD and VTSA without sacrificing performance. They also emphasize the Vivaldi antenna's compatibility with other circuits. These compact arrays are ideal for high-resolution medical applications like breast cancer detection (BCD) because of their high gain, wide bandwidth, directive stable radiation patterns, and low specific absorption rate (SAR). A simple BCD simulation scenario is addressed in this work. Detailed parametric studies are performed on the two arrays for impedance-matching enhancement. The computer simulation technology (CST) software is used for the simulation. Hardware measurement results prove the validity of the proposed arrays.Öğe Ultra-wideband (UWB) antennas for breast cancer detection with microwave imaging: A review(Elsevier B.V., 2025) Saeidi, Tale; Mahmood, Sarmad Nozad; Saleh, Sahar; Timmons, Nick; Al-Gburi, Ahmed Jamal Abdullah; Razzaz, FaroqIn recent years, microwave imaging has attracted much attention and offers several advantages over existing imaging systems. It allows for a thorough examination of biological tissues, making it possible to identify changes in their shape and pinpoint their exact locations. One exciting development in this field is ultra-wideband (UWB) microwave imaging, which delivers superior results while using radiation that is not harmful. Antennas are a crucial part of UWB systems and require careful optimization, especially considering their proximity to the human body. Various factors need to be considered when designing antennas, including the choice of materials and dimensions, operational bandwidth, the impact of the human body on antenna performance, and the dynamics of short-pulse propagation. Recent research has focused on improving electromagnetic sensors used in these systems, whether as standalone units or as part of antenna arrays. This paper aims to comprehensively review significant advancements in high-performance UWB antenna sensors used in microwave imaging systems utilized for breast cancer detection. © 2025 The Authors
