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A novel method is proposed to achieve a low-profile miniaturized dual-band dielectric resonator antenna (DRA) for wireless communication applications. The cylindrical dielectric resonator (DR) is fed by a microstrip loop on the top surface of the substrate and a mountain shaped ground on the bottom surface of the substrate. This structure not only effectively transfers energy to the DR but also plays a pivotal role in establishing a lower resonance frequency of 1.73 GHz, achieving this with a compact structure (0.21λ0 × 0.18λ0 × 0.02λ0, and λ0 is the free-space wavelength at 1.73 GHz). HEM11δ mode of the cylindrical DR is employed to cover the upper frequency band of 2.8 GHz. Ultimately, the effectiveness of our suggested approach and the antenna’s performance are confirmed through the measurement. [ABSTRACT FROM AUTHOR]

This research proposition introduces a novel microstrip antenna design that features triple notches for ultra-wideband (UWB) applications. The antenna, measuring 35.4 mm × 28.82 mm × 1.57 mm, incorporates rectangular and semi-circular slots, as well as a pentagonal stub. A modified U-shaped slot on the pentagonal stub creates one notched frequency band at 3.3–3.7 GHz. Additionally, two Split Ring Resonators (SRRs) are integrated into the antenna’s rear surface, resulting in two more notched bands at 5.1–5.8 GHz and 7.1–7.8 GHz. Operating within a frequency range from 3 to 11.2 GHz with VSWR ≤ 2, the antenna effectively excludes the triple stop bands at 3.3–3.7 GHz (11.4%), 5.1–5.8 GHz (12.8%) and 7.1–7.8 GHz (9.4%). The proposed antenna has been successfully prototyped and verified. An extensive result analysis has been conducted, confirming that the developed antenna is suitable for application in a range of wireless systems. Moreover, the article includes the implementation of an equivalent circuit for the proposed antenna. [ABSTRACT FROM AUTHOR]

This work presents a knowledge-based decision-making robust antenna design (KDRAD) method that employs a heuristic-optimisation technique for antenna design. The method is used to create and scale a single-element antenna to operate at multiple frequencies within the 5 G range. In this study, a low-profile planar four-element microstrip antenna of 14.8 mm × 14.8 mm × 0.508 mm gives simulated and measured impedance bandwidths of about 1.18 GHz (26.43–27.61 GHz) and 1.08 GHz (26.42–27.50 GHz), respectively, with a centre frequency of 27 GHz. The mm-wave planar four-port antenna has a maximum gain of 7.2 dBi; isolation of 33.2 dB; and multiple antenna matrices with minimal ECC (0.000000109), high diversity gain (10 dB) and channel capacity loss of 0.00110 bits/s/Hz. [ABSTRACT FROM AUTHOR]

Radio frequency (RF) energy harvesting finds application in wireless sensors, RF codes, smart switches, IoT device applications, etc. Contrary to batteries, RF energy harvesting is open to electromagnetic waves coming from different sources and there is no limitation on the dimension and duration of application. A RF energy harvester captures electromagnetic energy from the source to which it is exposed and convert this energy into usable DC voltage. In this paper we propose the fundamental unit of RF harvester, the microstrip patch antenna. Microstrip patch antenna comes with a host of qualities like small size, low price, simple design, less weight, easy fabrication and many more. The proposed microstrip patch RF energy harvest antenna is developed using FR4 substrate with dielectric constant 4.4 and loss tangent 0.009. The substrate comes in between the ground and copper metal patch. Selected target frequency of operations is 2.4 GHz and 5 GHz, which lie in the Wi-Fi band. A microstrip line of width 1.1 mm for 50Ω impedance load matching is used. The antenna is inset-fed. The design and simulation are carried out using High-Frequency Structure Simulator (HFSS) software and the antenna dimensions are due to standard antenna equations. Simulation results achieved gain of 7 dBi at 2.4 GHz with low return loss (S11 parameter). The return loss stands near – 13 dB. The gain of the RF harvester at 5 GHz frequency operation is obtained to be 6 dBi with a remarkable low return loss of – 28 dB. With the given results and stable omnidirectional radiation pattern, the proposed antenna design is suitable for energy harvesting application for mm wave application viz. Bluetooth, Wi-Fi, and WiMAX applications, as an alternate energy source meeting the global energy requirement due to increase in demand of power [ABSTRACT FROM AUTHOR]

A simple and compact polarization reconfigurable patch antenna design is proposed to operate in WLAN band at a resonant frequency of 2.4 GHz. This antenna consists of a rectangular patch placed on an FR4 substrate. A rectangular slot is cut in the rectangular patch. Two L shaped microstrip strips are placed inside the slot and joined together at the centre of the rectangular patch by inverting the L shaped microstrip. There are three different methods of achieving the reconfigurability namely electrical, mechanical and optical. This proposed structure uses electrical reconfiguration technique. This proposed antenna structure uses PIN diodes for achieving the polarization reconfigurability because of its ease in biasing. Two PIN diodes both being placed on the inverted L shaped structure in order to achieve the polarization modes and these PIN diodes are used to connect this microstrip with the rectangular patch. By switching these two PIN diodes for various biasing conditions, four different polarization modes namely two linear polarization (LP) modes, one Left Hand Circular polarization (LHCP) and one Right Hand Circular polarization (RHCP) mode is achieved. The antenna produces simulated gain of around 1.5416 dB for LP1 mode at 2.41 GHz, 1.7175 dB for LP2 mode at 2.45 GHz, 1.6062 dB for RHCP mode and 1.5922 dB for LHCP mode both at 2.4 GHz. The antenna structure is simulated using Ansys HFSS. [ABSTRACT FROM AUTHOR]

In this proposed article authors present the design and analysis of a miniaturized dual-notched super wideband (SWB) monopole microstrip antenna for various wireless communication applications. Initially a monopole reference SWB antenna is designed by semi-circular shaped radiating patch and perfectly positioned notch loaded reduced ground plane. Final proposed antenna structure incorporates properly positioned ‘U’ shaped slot on the radiating patch and a ‘U’ shaped parasitic strip resonator on the modified ground plane to eliminate mainly 5 GHz WLAN frequency band and 7.2 GHz satellite downlink frequency bands, respectively. The suggested antenna accomplishes two notch bands without the need of two separate filters. Thus, the suggested antenna is likewise smaller one also. Having a footprint of 26 × 27 × 1.588 mm3 the proposed antenna exhibits large impedance bandwidth of 22.64 GHz (2.48 to 25.12 GHz), fractional bandwidth of 164% and Bandwidth Dimension Ratio (BDR) of 3374. Mathematical analysis and modification processes that were included into the original reference antenna to meet the required design objectives have been presented. The proposed antenna has been designed and simulated. The suggested antenna is designed on a Rogers RT/Duroid® 5880 substrate (h = 1.588 mm, εr = 2.2, and tan δ = 0.0009) and simulated by using CST Microwave Studio Suite Software. [ABSTRACT FROM AUTHOR]

In this work, we have used the surrogate model assisted differential evolution (SADEA) to model a one and two-element inset-fed patch antenna array to optimize its parameters for efficiency and usability. The microstrip patch antennas operates in a frequency band of 2.4 GHz. The optimization process focused on fine-tuning the patch length, patch width, and notch width to enhance key performance metrics directivity, return loss, and bandwidth. The design is made in CST software with an FR-4 substrate and simulated in the ADE1.0 software a MATLAB toolbox. Significant enhancements were achieved including a directivity gain of 3.04 dB, and 5.58 dB a return loss of -19 dB, -16 dB, and an expanded impedance bandwidth from 0.0798 GHz, 0.0588 GHz to 0.0951 GHz, 0.0824 GHz respectively. The antenna was constructed and then measured. The findings showed that the measurements and the fabrication process closely matched, especially in terms of return loss. [ABSTRACT FROM AUTHOR]

This paper presents the design of 1x4 array microstrip antenna utilizing modified backline feeding technique at 5.8 GHz frequency band. The antenna, designed on flame retardant (FR-4) substrate with a dielectric constant of 4.4, aims to achieve reduced harmonics and mutual coupling between closely spaced antenna elements. The primary scope of the paper is investigating the performance of a single band microstrip antenna employing the proposed modified backline feeding method. Moreover, developed design came out with the result and critical analysis by various parameters such as, gain, return loss, voltage standing wave ratio (VSWR), and directivity. Therefore, the proposed design of microstrip antenna with backward linefeed (BLF) demonstrates a directivity of 10.29 dBi, return loss of -21.947 dB, and VSWR of 1.173; are significant improvement compared to recent literature shown in this paper. The adoption of proposed back line feeding technique (BLF) represents a promising alternative for addressing poor wireless connectivity issues in terms of antenna design, gain, and direction within microstrip technology. [ABSTRACT FROM AUTHOR]

In this paper, with the promising assumption of using adaptive directional microstrip antenna on user equipment, the problem of joint antenna selection, spectrum assignment, and transmit power allocation for mm‐wave device‐to‐device communications underlying cellular networks is tackled, with the goal of enhancing system throughput and energy efficiency. To address the complexity of this problem, a method based on multi‐agent distributed deep reinforcement learning in which an autonomous intelligent agent is deployed for each user equipment is proposed. The performance evaluation demonstrates its superiority over existing strategies, resulting in improved system performance, reduced outage probability, and enhanced energy efficiency. [ABSTRACT FROM AUTHOR]

A compressed small width circular in shape aerial with fractal characteristics that exhibits minimal delay, cost and better speed with wide band characteristics is modeled. Simulation analysis has been done with software named CST Microwave studio after that it has been verified by experimental analysis. Substrate material used for fabrication is easily available FR-4 (εr = 4.4) with 1.59 mm as thickness of sheet. The dimensions are 24 × 40 mm (W × L). Aerial finds its applications in mobile services. The 5 GHz band is perfect for high-bandwidth devices or activities such as online video games, conference calls and streaming. 6 GHz Wi-Fi range is applicable for recently used short-range, better efficiency, and low delay applications. Proposed antenna covers C, X and Ku bands and conducting from 2.93 to 9.53 GHz with VSWR ≤ 2. This aerial is also performing in ultra wideband (UWB), S, C and partial of the X range. [ABSTRACT FROM AUTHOR]

A new microstrip patch antenna design with a dual-wing construction is introduced to provide diverse multiband characteristics maintaining good antenna performance. The antenna exhibits resonances at multiple frequencies within the X-band due to the use of etched slots on the parasitic patch, considerably broadening its possible applications. This unique configuration is thoroughly investigated using numerical simulations as well as real testing. The proposed design showcases three distinct operational bands, operating at frequencies of 8.32 GHz, 10.33 GHz, and 11.69 GHz. These bands are supported by impedance bandwidths of 300 MHz (ranging from 8.21 to 8.51 GHz), 620 MHz (from 10.01 to 10.63 GHz), and 510 MHz (covering from 11.4 to 11.91 GHz). Furthermore, the antenna delivers favorable gains of 3.31 dB, 7.78 dB, and 7.48 dB at their respective frequencies. A commercially accessible electromagnetic simulation tool is used to simulate the antenna's design. This tool accurately predicts and analyses the performance of the antenna, validating simulated results with the experimental findings. The antenna has compact dimensions of 38 × 38 × 1.6 mm3 due to its unique design, which contributes to multiband capabilities and enhanced bandwidth. The antenna's wing form improves radiation patterns and surface current distribution. The directional flow of currents in distinct modes is recognizable at the three operational frequencies. This novel antenna design holds promise for applications demanding multiband capabilities and enhanced performance. [ABSTRACT FROM AUTHOR]

Nitrogen-vacancy (NV) centers in diamond are promising quantum sensors, where microwave antennas play a crucial role in manipulating the spin states accurately. Conventional microwave antennas often struggle to balance radiation efficiency and bandwidth. To address this challenge, we design a planar double-turn spiral antenna (PDTSA), based on the ring microstrip antenna (RMA). PDTSA demonstrates an ∼4.5-fold increase in radiation efficiency compared to RMA. In addition, the PDTSA allows linear tunability of the resonance frequency up to 500 MHz by adjusting the spiral input length. This feature addresses the limitations of a narrow working frequency range, which are typically caused by the narrowband in high-radiation-efficiency antennas. The experimental results show that at an absolute input power of 1 W, the PDTSA increases the Rabi frequency from 1.72 to 8.06 MHz compared to the RMA. This enhancement accelerates quantum state manipulation and reduces phase accumulation errors. These characteristics make PDTSA suitable for applications in quantum sensing and precision measurements using NV centers. [ABSTRACT FROM AUTHOR]

In this study, a frequency‐reconfigurable circular patch antenna with a varactor diode has been presented. The proposed antenna has been designed and investigated in four steps: circular patch antenna (Antenna 1), antenna with double slots (Antenna 2), antenna with quad slots (Antenna 3), and antenna with varactor diode (Antenna 4). The proposed antenna has been made compact with rectangular slots and a hyperabrupt junction tuning varactor diode (SMV1249‐079LF). The proposed antenna has been designed and produced in 32 × 32 × 0.64 mm3 dimensions, approximately 80% minimized compared to a microstrip circular patch antenna operating at 850 MHZ resonance frequency. This frequency‐reconfigurable antenna can perform between the range of 0.85–1.3 GHz frequency with 0–3 V DC voltage tuning of the varactor diode. So, using with the varactor diode, the proposed antenna has obtained a 53% tuning range between 0.85 and 1.3 GHz frequencies. This study offers a different antenna design, compactness, and high tuning ratio compared to previous studies. This frequency reconfigurable antenna can be preferred with its wideband structure in different communications areas and wireless energy transfer systems. [ABSTRACT FROM AUTHOR]

Microstrip antennas are increasingly utilized in space‐borne applications, spanning areas such as RFID, mobile communication, and healthcare. This paper introduces a novel wearable ultra‐wideband (UWB) microstrip patch antenna, distinctively designed in a star shape. The antenna, with a total volume of 1172 mmÂş, is crafted on a semiflexible substrate using RT/duroid 5880. It exhibits a low loss tangent of 0.0004 and a relative permittivity of 2.2. The proposed design achieves a resonant frequency of 3.4 GHz, an impressive reflection coefficient of −39 dB, and an extensive bandwidth of 5.6 GHz, ranging from 2.8 to 8.4 GHz. Although the antenna demonstrates modest gain and directivity, its expansive bandwidth is a significant attribute. This wideband antenna is proposed as an ideal candidate for wearable biomedical applications, leveraging its substantial bandwidth and unique design characteristics. [ABSTRACT FROM AUTHOR]

In this study, a single band 28 GHz antenna with defected ground structure (DGS) has been proposed. The integration of a DGS is explored to exploit ground plane defects for achieving wideband operation. Through systematic design and optimization, our approach achieves remarkable bandwidth enhancement, expanding from 0.75 GHz to 5.78 GHz, covering frequencies from 26.43 GHz to 32.21 GHz, resulting in an impressive impedance bandwidth of 20.5%. Notably, the proposed methodology significantly improves the reflection coefficient, reducing it from -16 dB to -57 dB. Furthermore, the antenna demonstrates a gain of 5.123 dBi and an enhanced voltage standing wave ratio (VSWR) of 1.0056348. Comparative analysis against existing works underscores the superior performance of our antenna design, affirming its potential for various applications. This work presents a novel DGS featuring a circular microstrip patch antenna (MPA) with dimensions of 8×8×0.5 m³, utilizing Rogers RT5880LZ substrate (E=2) with a thickness of 0.5 mm. [ABSTRACT FROM AUTHOR]

A ground station antenna system features a conical horn attached to a microstrip antenna as an alternate receiving feed antenna. The proposed microstrip antenna has circular polarization and operates in the X-band. The far-field parameters of the antenna are measured after developing and simulating the combination of a conical horn and a microstrip antenna. The modeling results for a microstrip antenna with a conical horn offer a working bandwidth of 930 MHz, spanning frequencies 7.44 GHz to 8.37 GHz. The axial ratio measurements for a microstrip antenna joined with a conical horn produce a working bandwidth of 150 MHz, covering frequencies ranging from 7.72 GHz to 7.87 GHz. The conical horn is attached to a microstrip antenna and has a gain of 15.1 dB. The proposed antenna is designed to meet ground station antenna requirements by pairing it with a parabolic reflector with a diameter of 3.7 meters. The primary focus antenna of the proposed design was chosen. The feed antenna and parabolic reflector should be positioned at a focus point distance of 1110 mm for a total gain of 38.9 dB at 7.8 GHz frequency. The proposed antenna can be applied on X-band remote sensing ground stations as a receiving antenna. [ABSTRACT FROM AUTHOR]

This paper presents a broadband magneto-electric dipole (MED) circularly polarized (CP) microstrip antenna array with continuous rotating feed (SRF). The antenna element consists of a quarter-circle ring with irregular cross slits and a rectangular patch. The energy is combined with four metallized perforations and then transmitted to the radiating block to better excite the magnetic dipole-electric dipole energy and expand the bandwidth. Then, a 2 × 2 subarray was designed to further increase the axial ratio(AR) bandwidth. Finally, a 4 × 4 circularly polarized array arranged in a diamond shape is designed to utilize sequential rotating feeds to further improve the gain for millimeter-wave applications. Simulation results show that the impedance bandwidth (IBW) of the proposed array is 54.5% (20–35 GHz), and AR bandwidth of 3 dB is 27.2% (22.2–29.2 GHz), and the maximum gain is 16 dBic. [ABSTRACT FROM AUTHOR]

A highly miniaturised electrically small square loop antenna has been designed for operation at 2.5 GHz. The antenna is loaded using a simple series combination of two lumped inductors and two interdigitated capacitors in order to realise inherent impedance matching at a given miniaturisation level with respect to a specified source impedance, without using any external matching network. The designed antenna has an overall size of 0.061λ0 × 0.061λ0, which is approximately 75.6% miniaturised in terms of total loop length and 94% miniaturised in terms of overall footprint. The designed antenna is fabricated and the corresponding impedance matching and radiation patterns are measured, which are found to be in reasonable agreement with their simulated counterparts. Moreover, an investigation with two closely spaced electrically small SLAs, one for transmitting and the other for receiving, is carried out in this work in pursuit of maximising the isolation, which plays a crucial role in the Tx/Rx systems. [ABSTRACT FROM AUTHOR]

This paper presents a low‐profile patch antenna with dual‐axis wide‐beam characteristics. The antenna includes a microstrip patch antenna and four parasitic patch elements. The study demonstrates that both the E‐plane and H‐plane beams can be extended by strategically placing these parasitic patches. The length and distance of these parasitic patch elements play a crucial role in achieving the desired wide‐beam characteristics. A prototype antenna operating at 5.8 GHz is fabricated and measured in an anechoic chamber to validate the concept and design parameters. The measured results confirm the extension of half‐power beamwidth in the E‐plane to 123∘$^{\circ }$ (133%) and in the H‐plane to 120∘$^{\circ }$ (153%). [ABSTRACT FROM AUTHOR]

Phased array antennas are frequently subjected to surface distortions due to environ-mental factors during operation. Such distortions can lead to a deterioration in the electrical performance of the phased array antenna. This study provides an in-depth analysis of the impact of array distortions on electrical performance indicators. An electronic compensation approach, employing an enhanced genetic algorithm, is proposed to mitigate the effects of these distortions. The conventional genetic algorithm has been augmented with an elimination mechanism to boost convergence. This method compensates for amplitude and phase by calculating each element's amplitude and phase of the excitation current, thereby enhancing the convergence performance. Simulations this approach, simulations of rectangular microstrip patch antennas are conducted to validate the effectiveness of this approach. The simulation outcomes reveal that the proposed method significantly improves the antenna's radiation pattern and all performance indicators, confirming its efficacy. [ABSTRACT FROM AUTHOR]

The possibilities for further development of mmWave fifth-generation wireless systems and their deployment in our lives are immense and will make human life simpler and faster. Fifth-generation wireless communication is opening up new possibilities for development in the near future. High data rates, low latency, and enormous bandwidth are the most essential factors. These factors are at the heart of making quality healthcare, smart education systems, and the fast and efficient distribution of energy. In account of the aforementioned benefits, 5G wireless systems are primarily made possible by high gain MIMO antenna with minimal coupling. The integration of traditional wave-guide components with planar circuits, on the other hand, is a difficult issue. SIW solves this problem by providing planar alternatives for waveguide-based devices like filters, antennas, and couplers. The SIW antenna has less interference, low radiation loss, excellent isolation, and outstanding shielding properties as compared with the conventional microstrip antenna. The proposed SISO SIW antenna has gain of 9.05 dBi with 87.54 % radiation efficiency. The −10 dB impedance bandwidth is 27.79–28.19 GHz. The SIW MIMO antenna has gain of 9.05 dBi with 81 % radiation efficiency. The antenna has an isolation 52 dB, and an ECC is 0.65 × 10−7 at 28 GHz. The proposed SIW MIMO antenna's MEG lies below −3 to −5 dB for Gaussian and isotropic medium. The CCL for the proposed MIMO antenna is 0.29–0.36 bits/s/Hz in the operating band. This article presents a high-gain and high-isolation substrate integrated waveguide (SIW) MIMO antenna using orthogonal diversity for increasing isolation between the radiating elements. The designed MIMO antenna is operating in the 28 GHz band (27.42–28.79 GHz), which comes under the n261 (FR2 5G-New Radio frequency band) band used for 5G wireless communication. [ABSTRACT FROM AUTHOR]

This study investigates the effects of various antenna parameters, such as the substrate material, thickness of the superconducting patch, and operating temperature, on the resonance frequency and surface resistance/reactance of an H-shaped patch antenna printed on a uniaxial anisotropic substrate using a hybrid cavity model and fabricated with superconductor material. This model stands out for its simplified mathematical approach and cost effectiveness. Importantly, the numerical results demonstrate a high level of agreement with the experimental findings reported in the literature, reinforcing the reliability of our study. Additionally, other numerical results demonstrate the impact of the superconductivity materials on the resonant characteristics of the H-shaped compact microstrip antenna. [ABSTRACT FROM AUTHOR]

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Textile-based antennas are of great importance for wearable devices due to their flexible and compact design, which allows the creation of efficient wearable technologies. However, the use of flexible substrates in wearable antennas presents a number of challenges, including frequency shifts that occur during bending. A comprehensive analysis of the bending characteristics of flexible substrates is absent from the existing literature. The objective of this study is to analyze the performance of a Wi-Fi Microstrip Patch Antenna (MPA) designed to operate at 2.4 GHz using flexible substrates, such as leather, fleece, and felt, with a detailed examination of their bending characteristics. A bending analysis was conducted to measure the impact on performance metrics, such as return loss, bandwidth, gain, and Voltage Standing Wave Ratio (VSWR) under bending angles from 0° to 17°. The leather substrate exhibited minimal degradation in performance. The antenna demonstrated a return loss below -15 dB, a bandwidth exceeding 4%, a gain exceeding 5 dB, and a VSWR lower than 2.5 across all tested conditions. The leather substrate has emerged as a promising candidate for wearable Wi-Fi applications due to its ability to maintain stable performance metrics under bending conditions. [ABSTRACT FROM AUTHOR]

A dual-band, dual-pattern antenna is presented for 1.437 GHz L-band and 2.45 GHz Industrial Scientific and Medical (ISM) band applications. The antenna is based on multilayer circular patches with symmetric slots and two asymmetric cylindrical vias that shorten the multiple layers with the ground plane using Plated Through-Holes (PTHs) to generate the required resonant modes. The first mode is operated at 1.437 GHz, providing an omnidirectional radiation pattern, while the second mode is operated at 2.45 GHz, providing a directional or broadside radiation pattern. The antenna was fabricated to validate the simulation results and excellent agreement was found between the simulation and experimental results. The antenna has a total size of only 6x6x0.443 cm³, which corresponds to an electrical size of 0.5λ0x0.5λ0x0.03λ0 at 2.45 GHz and 0.28λ0x0.28λ0x0.02λ0 at 1.437GHz, thanks to the loading effect of shorting vias. The gain of the antenna is 1.62 dBi at 1.437 GHz and 6.48 dBi at 2.45 GHz, along with quite good radiation efficiencies of 83.4% and 96%, respectively. For body-centric applications, the performance of the antenna was also examined in close proximity to the human body. Nearly stable performance was found in close proximity to the human body, comparable to free space performance in terms of both impedance matching and radiation patterns. The 10g Specific Absorption Rate (SAR) of the antenna was also measured and found to be below the international compliance limits. These characteristics make the antenna a very promising choice for body-centric communications. The antenna also applies to other wireless systems such as MIMO, wireless ad hoc networks, etc. It offers radiation pattern diversity in a single planar package with a highly flexible and adaptable design by providing much more degrees of freedom than classical microstrip antennas. [ABSTRACT FROM AUTHOR]

Summary In this paper, a 4 × 4 MIMO (multiple‐input multiple‐output) antenna with metasurface (MS), which is composed of dual circularly polarized (CP) patch antennas, is proposed for 5G (sub‐6 GHz) applications. The MIMO antenna consists of four microstrip patch antennas. In order to improve the isolation of the MIMO antenna, parasitic elements are placed on the MS and layer of patch antennas. In addition, a substrate‐integrated waveguide (SIW) structure is used at the center of the MIMO antenna for this purpose. The proposed MIMO antenna is fabricated for validation tests. The antenna has overall dimensions of 115 mm × 115 mm × 3.2 mm (1.219 λ0$$ {\lambda}_0 $$ × 1.219 λ0$$ {\lambda}_0 $$ × 0.033 λ0$$ {\lambda}_0 $$, where λ0$$ {\lambda}_0 $$ is the free space wavelength at the lowest operating frequency in 10‐dB impedance bandwidth). The MIMO antenna has 10‐dB impedance bandwidth (IBW) from 3.3 to 3.8 GHz (14.08%), 3‐dB axial ratio bandwidth (ARBW) from 3.42 to 3.69 GHz (7.59%), and 6.36‐dBi peak gain. The isolation is greater than 28.14 dB in the n78 frequency band (3.3–3.8 GHz). [ABSTRACT FROM AUTHOR]

This review offers an extensive examination of the evolving landscape of Long Range (LoRa) Microstrip Patch Antennas (MPAs), highlighting their crucial role in optimizing LoRa systems within the Internet of Things (IoT). As the demand for energy-efficient standards like LoRa grows with the expanding IoT market, this research becomes increasingly relevant. This comprehensive review, the first of its kind, serves as a foundational resource for researchers seeking to optimize LoRa systems within the IoT. The study has categorized these LoRa MPAs – including monopole, Planar Inverted F Antenna (PIFA), dipole, yagi-uda, and array – into single band, dual-band, multiband, and wearable antennas, thus providing substantial viewpoints on their diverse design architectures and performance characteristics. Through systematic tabulation, the review facilitates a thorough comparison of antenna advancements. Notably, the review addresses inherent challenges in LoRa MPAs, emphasizing critical aspects that necessitate attention, including the need for miniaturization and integration, advancements in substrate materials and fabrication techniques, and the imperative for reconfigurable and adaptive antennas. Various approaches to enhance antenna performance are explored, including the metamaterial incorporation, slot-based enhancements, Electromagnetic Band Gap (EBG), dielectric resonator antennas (DRAs), substrate material considerations, and corrugation techniques. Looking ahead, the paper explores the future trends and subtle considerations that are poised to shape the trajectory of LoRa MPAs. To the best of our knowledge, this paper represents the first comprehensive review on the multifaceted topic of LoRa MPAs, serving as a foundational resource for researchers in the field. [ABSTRACT FROM AUTHOR]

Summary: A compact, double‐sided four‐port printed antenna with pattern and polarization diversity performance is proposed for super‐wideband (SWB) applications. The proposed printed antenna consists of microstrip line‐fed corner truncated four identical square patches. One pair of patches is placed strategically on the top side of the substrate, and another pair is on the bottom side with rotational symmetry to realize a compact four‐port antenna with higher port isolation (>25 dB) throughout the operating band along with pattern diversity. A half‐circular slit is etched in the partial ground plane of all four antennas to achieve SWB (1–19.81 GHz) response. A meander‐shaped decoupling structure is incorporated on both sides of the substrate to enhance the port isolation. T‐shaped slots on the patch and corner truncations are conceived to achieve circular polarization (CP) across 5.15–5.83 GHz. The beauty of this structure lies in the easy switching between LHCP and RHCP by just controlling the port excitation. Moreover, the strategic placement of antenna elements produces bidirectional patterns with proper choice of port excitation. A good agreement is observed between the measured and simulation results. [ABSTRACT FROM AUTHOR]

Summary: A design problem of multiband multi‐input, multi‐output (MIMO) antenna arrays for maximal side lobe level lessening with constraint of a fixed beam width is dealt with. Multiband MIMO antenna is the most promising solution in a communication system, due to its maximal speed, higher data rate, and short‐range communication. Conversely, MIMO faces several complications including designing a proper antenna for a specific bandwidth and lesser antenna efficacy. In this manuscript, a high‐resolution CP multiband MIMO (HS‐CPMB‐MIMO) antenna design for wireless communication is proposed. MIMO antenna plays a vital part in the present wireless technology at MSA. A multiband microstrip line‐fed two‐port hybrid CPMIMO antenna is intended and fabricated. The proposed microstrip feed antenna contains a tapering structure, and the inverted L‐shaped slots in the radiating element are opened on both sides to present notches in sub‐6‐GHz frequencies. The inverted L‐shaped slots is positioned in the middle of asymmetric Z‐shaped radiating elements for enhancing the isolation among the two ports. The invention of a multiband MIMO antenna with four CP bands has an efficient ECC value because of a large L‐shaped slot in the ground as well as a protruding Z‐shape ground stub embedded with circular rings to have highly isolated cells. Finally, the proposed HS‐CPMB‐MIMO antenna design is implemented by utilizing simulation software CST Microwave Studio, and it is evaluated with the performance metrics. The simulation outcomes of the proposed HS‐CPMB‐MIMO antenna provide 36.34%, 57.36%, and 25.33% higher BW, 24.13%, 15.96%, and 21.22% higher gain compared with existing methods. [ABSTRACT FROM AUTHOR]

Summary: To improve the gain of the corner‐slotted, wideband microstrip patch antenna (MPA), a three‐dimensional (3D) hemispherical dielectric lens (DL) and dielectric cylinder‐based hybrid structure is introduced. DL is constructed and integrated on the surface of the patch antenna to increase the gain performance. Three‐dimensional printing techniques contribute considerably to lens production. The 3D manufacturing technique provides greater freedom and versatility than conventional manufacturing methods. The DL increased the proposed single‐patch antenna gain from 6.2 to 13.7 dBi with stable gain fluctuation in the working frequency spectrum spanning between 27.5 and 31 GHz. This implies a notable increase in gain of 7.5 dBi and a consistently uniform gain characteristic throughout a 5‐GHz wide frequency range. Furthermore, the DL‐loaded antenna parameters such as |S11|, gain (dBi), axial ratio (AR), radiation efficiency (%), and radiation patterns measured results are compared with simulated plots. Overall, the measured results agree well with the simulated findings. Based on the results, the compact antenna can be chosen for different wireless applications, especially for satellite communication in the proposed band. [ABSTRACT FROM AUTHOR]

Summary In this paper, a high gain self‐triplexing antenna based on the substrate integrated waveguide (SIW) leaky wave technology is presented for tri‐frequency operation. Three identical T‐shaped slots are embedded on the upper layer of the proposed SIW antenna, which are energized by two tapered microstrip lines and a simple microstrip line; and the antenna resonates at three different frequencies (7.75 GHz, 9.1 GHz, and 10.15 GHz). The transverse part of the T‐slot achieves the first band (8.8 to 9.3 GHz), while the longitudinal part of the T‐slot achieves the second band (9.6 to 10.9 GHz), and when excited transversely, the T‐slot achieves the third band (7.5 to 8.2 GHz). The isolation level between the ports is more than 25 dB, which contributes to the phenomenon of self‐triplexing. The gain of the presented antenna is high when compared with other self‐triplexing antennas. [ABSTRACT FROM AUTHOR]

The growing demand for space-efficient antennas compatible with portable electronic gadgets inspired the integration of recursively iterated fractal geometries (characterized by self-similarity, space-filling, and multiband/wideband capabilities) in antenna designs. Therefore, this article conducts an extensive survey on fractal-based single-port and multi-port patch antenna designs with multiband and ultrawideband characteristics for their implementation in 5G/IoT (Internet of Things) devices. The survey begins with a basic overview of fractal geometries and the iterated function system (IFS) technique employed for their generation. Further, it highlights the limitation of multipath fading prevalent in single-port antenna arrays that can be overcome by adopting multiple-input multiple-output (MIMO) technology. The MIMO antenna systems are vital for 5G networks to enhance data transmission rate, network capacity, and system reliability. Apart from these admirable attributes, the closely packed antenna elements in the MIMO configuration result in a severe mutual coupling. To address this limitation, various isolation enhancement techniques developed by distinguished researchers are thoroughly discussed in this article, detailing their merits and demerits. At last, this article portrays diverse band-notch structures integrated into the antenna designs to eradicate the existing interfering narrow bands in the ultrawideband (UWB) spectrum. The underlying reason for conducting this survey is to aid antenna designers and academicians with a thorough knowledge of distinct fractal geometries, various isolation improvement approaches, and band-notch techniques on a single platform, desired for designing 5G/IoT-based antenna systems. [ABSTRACT FROM AUTHOR]

In this manuscript, Conformal Mapping Technique (CMT) is applied to predict the resonant frequency of an Equilateral Triangular Microstrip Antenna (ETMA). The ETMA is mapped into a simple circular geometry with the aid of CMT. The wave equation is solved in the transformed domain using Galerkin technique to obtain the approximate solution of eigenfunction and eigenvalue. Twenty-three measured data are collected from the open literature to validate our theory. Our theoretical results are also compared with several CAD models to show the effectiveness of the present theory. It is found that our proposed theory can predict the resonant frequency of the ETMA with an error of less than 1.5%, whereas those CAD models can produce a large error (sometimes, 10-19% error). Internal field patterns, input impedance, far-field radiation patterns, quality factor, bandwidth gain, and directivity of the ETMA for the dominant mode are also investigated using CMT. [ABSTRACT FROM AUTHOR]

Cogeneration helps to optimise the energy consumption in modern greenhouse systems. A cogeneration plant produces electrical and thermal energy close to the greenhouse. Thermal energy is used for heating the plants, while electric energy powers the lights. A patent from the University of Genoa proposes to use part of the electricity produced by the cogeneration system to power a low-power microwave heating system that provides additional thermal energy input to the plants. This innovative approach showcases the integration of diverse energy sources for enhanced efficiency. The project aims to create a cost-effective dielectric heating system with feasible installation expenses, underpinned by a comprehensive analysis of power requirements and electric field dynamics that are essential for optimal plant heating. Four microstrip antennas for microwave generation have been designed. Their performance has been compared. A laboratory and an industrial prototype of microwave heaters have been created. The results are discussed. The successful testing of a prototype heater in a small greenhouse environment is a significant step towards the feasibility of this heating solution. The modular heater proposed makes the product suitable for different greenhouse sizes. [ABSTRACT FROM AUTHOR]

This letter proposes a novel four‐degrees of freedom (4‐DOFs) antenna for 5.8 GHz wireless local area network band communications. The proposed antenna realizes 4‐DOFs with a low profile (0.11λ), which is composed of ±45°‐polarized dipole (DP), an artificial magnetic conductor (AMC) reflector, and a dual‐polarized slot‐loaded microstrip antenna (MA). The whole size of the proposed antenna is 83 mm × 83 mm × 5.9 mm (1.6λ × 1.6λ × 0.11λ). The DP is printed on the substrate with the wideband characteristic, and the MA operates at TM50 mode. The AMC reflector operating for the DP is designed for the low profile, causing the low isolations between the DP and the MA. The broadside radiation with 4‐DOFs is first reported. The envelope correlation coefficients are lower than 0.07, and the DOFs are 3.75. The measured results are in accord with the simulated results. [ABSTRACT FROM AUTHOR]

In the field of antenna optimization design, traditional electromagnetic softwares adopt the method of sweeping with parameter, which causes the problems of large amount of calculation and low efficiency. In view of this problem, a joint optimized design based on flamingo search algorithm and HFSS (High Frequency Structural Simulator) is proposed in this study. This method is realized through the co-simulation of MATLAB and HFSS. MATLAB generates a VBS (Visual Basic Script) script for HFSS to call by writing the code of the design and simulation about antenna in MATLAB. HFSS returns the result of electromagnetic simulation to the function about fitness calculation. The flamingo search algorithm optimizes the particle position according to the fitness value until the optimal result is found and the optimal antenna size parameters are determined. In the co-simulation design, the optimal size parameters are found after 23 iterations, so that the fitness value of the optimized antenna in the two working frequency bands is optimized from -483.37 dB to -771.15 dB. The results of simulation show that the proposed algorithm has strong optimization ability and fast speed of convergence, which significantly improves the efficiency of the design of antenna optimization. [ABSTRACT FROM AUTHOR]

In this paper, a novel method for detecting breast cancer utilizing an ultra-wideband (UWB) microstrip patch antenna operating in the UWB frequency range is presented. The promise of non-invasive, radiation-free breast cancer screening is provided by UWB technology. We give a brief overview of the difficulties in detecting breast cancer as well as the benefits of UWB technology in medical applications in this study. This study presents a compact printed microstrip patch antenna used for the bio-medical application at industrial, scientific, and medical (ISM) and UWB frequencies. The proposed antenna consists of a hexagonal-shaped microstrip patch antenna with a slotted ground antenna used for high bandwidth for a wider range of applications. The compact biomedical antenna is printed on Roger 5880 substrate with an overall dimension of 25*25 mm. Due to the high demand for results accuracy, Roger 5880 substrate material is used because it has good dielectric characteristics and loss factors that are appropriate for medical and radio frequency (RF) applications. A 50-ohm impedance line is used to feed the antenna. The proposed antenna has a higher bandwidth of almost 12.5 GHz at such a low frequency, starting from 3.53 to 16 GHz. The antenna has an acceptable gain of 3.38 Db, which is enough for the required application. The UWB microstrip patch antenna has the potential to improve breast cancer detection accuracy and reliability, which would aid in early diagnosis and better cancer patient treatment. This work represents a major advancement in the development of non-invasive, low-cost breast imaging methods for early cancer diagnosis. [ABSTRACT FROM AUTHOR]

A microstrip circularly polarized (CP) leaky-wave antenna (LWA) operating in the X-band, and having the characteristics of a broad axial ratio bandwidth is proposed. The proposed LWA is made up of 13 unit cells in series through microstrip feeding lines. Elliptical and rectangular slots are etched in each unit cell to achieve the radiation of CP waves. The open stopband at the broadside frequency can be suppressed by shifting the feeding line position and etching two circular notches on both sides of each radiation patch. To validate the proposed method, a prototype antenna operating in the X-band is manufactured and measured. The measured result demonstrates that the -10-dB impedance bandwidth of the microstrip CP LWA is 42.2% (7.96-12.22 GHz); the 3-dB axial ratio bandwidth is 26.4% (9.2-12.2 GHz); the gain of the antenna is 16.0 dBic. Besides, the main beam maintains good CP radiation properties while it continues to scan from -22° to +18°. [ABSTRACT FROM AUTHOR]

Antennas are of great importance in energy harvesting systems. It is possible to collect more energy with RF energy harvesting systems by using multiband antennas. In this study, a microstrip antenna was designed and fabricated for operation at 307 MHz, 1721 MHz, and 5447 MHz carrier frequencies. The designed multiband antenna with size of 82.05x104.76x1.60 mm3 was optimized for collecting more energy and then, implemented on FR4 substrate. Return loss, voltage standing wave ratio, and impedance of the manufactured multiband microstrip antenna were measured by vector network analyzer. The multiband antenna gain was calculated as 2.02 dBi. Furthermore, a good agreement was noted between the measurement and simulation results of the multiband microstrip antenna. As a result, it is determined that the produced multiband microstrip antenna is a useful and suitable antenna for RF energy harvesting circuits. [ABSTRACT FROM AUTHOR]

The paper proposes a single antenna that can generate dual‐mode plane spiral orbital angular momentum (PS‐OAM) beams. Six Vivaldi antennas placed in a tangential circular array make up the antenna, and the antenna is etched onto a substrate material and has a flat design, allowing for easy integration with other system components. The neighbouring ports of the antenna elements have phase differences, so phase‐shifting in the feeding network is unnecessary. When fed with the same phase and amplitude, the antenna can produce PS‐OAM beams with mode +1 at 7 GHz and mode +2 at 14 GHz, and the measured purity is 80.6% and 63%, respectively. The method may provide a new way to produce multi‐mode orbital angular momentum. [ABSTRACT FROM AUTHOR]

A circular polarization (CP) compact single-layer millimeter-wave antenna is proposed for 5G communication systems. The antenna is excited by a microstrip line. Its design is inspired by the Exotic Tri Shakti shape (L = 35.44 mm, W = 45.65 mm), which combines three different shapes: Trishul, Om and Swastik. The primary objective of this research is to design a CP antenna. The antenna is designed using RT/Duroid 5880 (ɛr = 2.2) substrate material, The choice of this substrate material is crucial in achieving the desired antenna performance. The proposed antenna shows multiple resonant frequencies with the max gain produced by the antenna are 15.03 dBi, 14.51 dBi, and 14.27 dBi at frequencies 40.42 GHz, 41.38 GHz and 53.43 GHz respectively and the max efficiency of 99% at the frequency 30.41 GHz (VSWR ≤ 2). The max impedance bandwidth is 3.05 GHz for the frequency range (25 GHz-60 GHz) and the Axial ratio bandwidths are 60 MHz and 13 MHz at frequencies 40.42 GHz and 57.19 GHz respectively. [ABSTRACT FROM AUTHOR]

This article introduces a compact, inconspicuous antenna designed for 5G wireless communications, utilizing a broad-spectrum meta surface. The suggested antenna employs an FR4 epoxy substrate with a dielectric constant of 4.4 and a thickness of 1.6. It is engineered to resonate at a frequency of 34 GHz for the meta surface radiator. Employing HFSS, the proposed radiator is replicated to assess the antenna's functionality with appropriate operational characteristics. The meta surface antenna exhibits a bandwidth spanning 28 GHz to 41 GHz, featuring a maximum reflection coefficient of 50 dB, utilizing a low-profile antenna with dimensions of 2.27λ0 × 2.27λ0 × 0.186λ0, the final outcomes were both designed and measured. The measurements reveal that the recommended antenna achieves a 10 dB impedance bandwidth, accompanied by a gain of 9 to 10 dBi and an optimal axial ratio. The performance of this unobtrusive, highgain microstrip antenna is primarily contingent on its radiating parameters. The meta surface plays a crucial role in regulating radiating properties, creating stringent operating conditions for the proposed antenna. In line with cutting-edge technology, communication systems demand additional resources and circular polarized radiation for the comprehensive operation of 5G antennas. The meta surface can be configured to optimize gain and reshape the radiation pattern, enhancing both bandwidth and gain. [ABSTRACT FROM AUTHOR]

In this proposed article authors present the design, analysis and development of the hybrid shaped multiband microstrip patch antenna for various wireless communication applications. Multiband characteristics of the proposed antenna is achieved by modifying the conventional circular radiating patch into “DUMBBELL” shaped hybrid patch geometry along with slotted reduced finite ground plane. A circular shaped reference patch is modified into dumbbell shaped patch by loading another circular shaped patch. Initial ground plane of same dimension as substrate is first decreased in width and four rectangular shaped slots are loaded in the appropriate locations to construct the final ground plane. Physical and electrical dimension of the proposed antenna are 24 mm × 40 mm × 16 mm and 0.18λ × 0.3λ × 0.12λ where λ represents wavelength corresponding to lowest operating frequency of 2.3 GHz. Proposed antenna is designed using FR-4 substrate (1.6 mm thick, loss tangent (tanδ) of 0.02, dielectric constant (εr) of 4.4) and simulated by CST Microwave Studio software. Antenna prototype is fabricated, measured and compared with the simulated results. The proposed hybrid shaped antenna exhibits measured multiband characteristics (2.3-2.5 GHz, 2.6-3 GHz, and 6.9-7.1 GHz) with centre frequency at 2.4, 2.7 and 7 GHz. Observed Reflection Coefficient, efficiency, peak gain and E plane and H plane radiation pattern of the antenna are very close to simulation result. Antenna can be suitably used for 2.4 GHz Wi-Fi and Bluetooth application, 5G mid band spectrum (3 GHz) and 7 GHz VSAT applications as well. [ABSTRACT FROM AUTHOR]

This work proposes the integration of a monopole antenna with a frequency selective surface (FSS) with double square loop geometry, which operates in the ISM (2.4 - 2.4835 GHz) and IEEE 802.11 WLAN (5.15-5.725 GHz) bands. The FSS was developed to be integrated into a microstrip monopole antenna, aiming to improve some of its radiative features, such as gain, directivity, and front-to-back ratio (FBR). We show that the double square loop FSS operates in bands from 1.91 to 3 GHz and from 4.64 to 6.56 GHz, fully covering the bands of interest. A prototype of the proposed structure was assembled and both the numerical simulation and the experimental results show that the antenna integrated with FSS presents significant improvements in all parameters, compared to the antenna without FSS. Because of the interest frequency ranges the proposed structure can be applied in non-invasive biomedical applications. [ABSTRACT FROM AUTHOR]

A new type of compact line-fed MIMO antenna for 5G wireless communication is presented in this paper. A rectangular microstrip patch antenna with an inset feed is designed for the 28 GHz and 38 GHz bands. T-shaped patch contains inverted I-shaped slots, providing a dual-band response at 28 GHz and 38 GHz. By integrating two T-shaped patches, the MIMO (Multiple Input Multiple Output) antenna significantly improves signal diversity and data throughput, making it highly suitable for modern wireless applications such as 5G networks. Slot-formed defected ground structures (DGSs) are inserted into a partial rectangular ground plane. To fit into handset devices for the upcoming 5G mobile revolution, the antennas are modestly configured on a substrate measuring 14×28 mm², occupying minimal area and reducing mutual coupling. The ECC, MEG, TARC, and radiation efficiency values obtained from the antenna systems are suitable for 5G mobile applications, with excellent reflection coefficient characteristics. [ABSTRACT FROM AUTHOR]

A broadband artificial magnetic conductor (AMC) metasurface for radar cross section reduction is proposed. Modified Jerusalem cross unit and quasi-circular unit can achieve effective reflection phase difference of 180° (±37°) within a wide frequency range from 8.95 to 17.3 GHz. The broadband metasurface consists of chessboard-arranged 3 × 3 block arrays, and each block array is composed of 4 × 4 AMC units. The proposed AMC metasurface is applied to a microstrip antenna for reducing RCS. The measurement results show that the low RCS antenna can obtain 10 dB RCS reduction from 7.93 to 17.5 GHz. The relative bandwidth is 75.2%, and the maximum reduction value is 30.2 dB. Also, radiation performance of the antenna is well maintained. [ABSTRACT FROM AUTHOR]

This study investigates the potential for significant enhancements in the gain and return loss of a microstrip antenna through the meticulous design of slits and a triangular slot in the radiation patch, coupled with precise dimensioning of these elements and careful selection of the feeding point. To this end, a microstrip patch antenna with multiple slits and a triangular slot was designed and simulated on an FR-4 with a dielectric constant (ε) of 4.4. In the initial configuration, the antenna exhibited a gain of 2.3 dB at 5.79 GHz for the maximum Eɵ at θ = 6º, with an S11 value of -16.5 dB. The antenna biasing and feed position were carefully optimized to achieve the desired performance improvements, in addition to meticulous design considerations for gain and return loss enhancements. The optimized antenna demonstrated a gain of 6.2 dB at 6 GHz for Eɵmax at θ = 0º, along with an S11 value of -24.3 dB. The final optimized configuration was fabricated and subjected to rigorous laboratory measurements for validation. The proposed antenna demonstrated an S11 value of -18.6 dB, along with a corresponding gain of 5.4 dB for Eɵmax at θ = 0º at 6 GHz. Furthermore, it was observed that the bandwidth increased by 330 MHz compared to its initial state. Finally, a comparative table is presented comparing the proposed antenna with other similar antennas found in the literature. Based on this table, it is evident that the gain enhancement can be achieved in a remarkable manner without altering the overall dimensions of the antenna and without the need for an expensive substrate with high permittivity. [ABSTRACT FROM AUTHOR]

This paper presents microstrip patch antenna array inspired by split ring resonators (SRR) for 5.8 GHz applications. The proposed microstrip patch antenna array inspired by split ring resonators is designed using FR-4 material with dielectric constant of 4.4, 1.6-mm thick substrate and loss tangent of 0.02. The split ring resonator has been loaded into the designed microstrip antenna array. Unloaded antenna arrays have a gain of 5.41 dB at 5.8 GHz, However split ring resonator-loaded antenna arrays provide a gain of 7.28 dB at the same 5.8 GHz resonant frequency. This microstrip patch antenna array inspired by split ring resonators is simulated using 3DEM of Mentor graphics electromagnetic simulator. To verify the theoretical and simulated results, antenna measurements are being prepared. [ABSTRACT FROM AUTHOR]