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A novel Ultra Wide-Band (UWB) frequency reconfigurable filtering antenna (or reconfiltenna) is presented in this research article. In the first step, a stepped-flower-shaped UWB antenna is optimized having a 3.5–14.1 GHz band. In the next step, a UWB filter with two stubs is designed to pass the frequency band from 3 GHz to 11.2 GHz having a stop band (notch) in between them from 5.9 GHz to 7.1 GHz. Then, the filter is merged with the feedline of the UWB antenna. The radiating patch is coupled at the output of the filter forming the filtering antenna or filtenna. This filtenna operates from 3.52 GHz to 10.1 GHz with a notch band of 5.42 GHz to 6.8 GHz. Finally, six PIN diodes are embedded in the stubs of the filter to vary the effective length of the stubs by switching ON/OFF the PIN diodes in different combinations. This variation, in turn, produces a controllable or trackable notch-band. The proposed reconfiltenna carries a small volume of 32 mm × 27 mm × 0.2 mm with a thin photo paper substrate. It produces a maximum gain and efficiency of around 7.54 dBi and 83% respectively. The simulated outcomes are cross-referenced and confirmed through comparison with experimental results. [ABSTRACT FROM AUTHOR]

The paper presents an UWB antenna for on-body application with advancements in EBG backed reflector incorporating the compatibility and flexibility in structure. The ultra-wideband (UWB) frequency range supported by the designed antenna is between 2.78 GHz and 18 GHz. The antenna is designed with jeans textile substrate for the compatibility in on-body applications, which has appealing qualities such as flexibility and low dielectric properties, while the antenna radiator patch and ground plane are made of copper. The designed antenna is applicable on human body, meticulously designed EBG surface that could minimize antenna frequency detuning, with specific absorption rate (SAR). This allows for a great deal of flexibility in terms of the antenna design, allowing it to realize a high gain, enhanced bandwidth and directional radiation pattern. The antenna gain is increased by 99.8 % once EBG is applied and the SAR is decreased from 22.03 W/kg to 0.104 W/kg. [ABSTRACT FROM AUTHOR]

Continuous observation, recognition and classification of various body movements and activities is essential for the implementation of Wireless Body Area Networks (WBAN) to discern the status of body parts functionalities or abnormalities if any. WBAN can continuously observe various movements of human body parts and human body activities. Recognition and classification of arm activities plays an important role in fitness monitoring, assisted living, and sports tracking, etc. In the presented work, Ultra Wide Band antennas are designed and employed on human body to observe datasets of antenna performance parameters associated with various arm movements and activities. The classification of three arm activities i.e. boxing, rowing, and clapping are implemented using Support Vector Machine, K-Nearest Neighbor, Random Forest and Decision Tree machine learning algorithms. Performance of classification depends on accuracy of implemented algorithm. The highest classification accuracies are found to be 99% in case of Decision Tree algorithm. [ABSTRACT FROM AUTHOR]

This work proposes a small circular monopole antenna with reconfigurable dual bandnotch characteristics designed for ultrawideband (UWB) applications. To provide tunable bandnotched characteristics, varactors are stacked in two via fractal (TVF) and mushroom electromagnetic band gap (EBG) structures. The first varactor diode is in the TVF EBG tuning band notch frequency for the WiMAX band (2.8-3.5 GHz). The second varactor diode is situated at the mushroom EBG tuning band notch frequency for the satellite downlink communication (5.9-7.9 GHz) X band. WiMAX and the X-notched band are achieved by varying the tuning of the varactors. Band notch characteristics is constantly reconfigured by adjusting reverse bias voltage across the varactors. The antenna structure is fabricated on FR4 substrate with a size of 24 × 24 mm2 which provides a size reduction of more than 25% with respect to recent literature. Proposed antenna give a large bandwidth (S11< -10 dB) from 2.8 to 12.0 GHz, excluding notched bands. The band notch frequency is continually adjusted from 2.8-3.5 GHz, and 6.0-7.9 GHz by adjusting the capacitance of the varactor diode from 0.487 to 2.35 pF. The simulated and measured results indicate that the proposed antenna is a good candidate. [ABSTRACT FROM AUTHOR]

Introduction: This paper proposes a novel all-dielectric design of lens antenna and its performance is optimized using genetic algorithm (GA). The optimization objective are 1-dB and steady gain that are directly optimized. The GA also optimizes the topological design of the lens. Methods: The method consists of two main components: the design of the objective function and the initial population selection. The first lens structure fed into the algorithm and the initial population match. The lens has a diameter of 150 mm and a thickness of 30 mm at its thickest point with working frequency of 6–18 GHz. The 3D printing technology is used for the antenna fabrication that reduces the implantation cost. Results: The experimental results show that the gain and peak aperture efficiency of the proposed antenna are 23.8 dBi and 51.9%, respectively, better than those of the existing designs. Discussion: It advantages are low-cost, easy to fabricate, simple design, high gain, narrow beams, low side lobes. It can be used in future ultra-wideband (UWB) applications. [ABSTRACT FROM AUTHOR]

In modern wireless communication, ultra-wideband (UWB) antennas are becoming increasingly popular. A novel compact MIMO antenna with a unique "Palms-Up Together" shape, symbolizing a praying gesture linked with specific religious sects is shown in this paper. With a remarkable impedance bandwidth of 171%, the antenna can cover almost the whole UWB spectrum, from 2.2 to 27.7 GHz. It attributes nine distinct resonance frequencies and a gain ranging from 2.9 to 9.5 dBi, except at 10.4 GHz. The antenna's performance was simulated using CST software, revealing four hexagonal slots in the truncated ground plane that improved impedance bandwidth. A simple stub improves isolation and reduces mutual coupling between radiating elements. The antenna measures 0.36λ * 0.28λ, where λ is the wavelength at 2.2 GHz. At lower frequencies, the stub ensures sure isolation stays below 15 dB, and at higher frequencies, it remains below 20 dB. The design satisfies essential performance requirements, as demonstrated by the results of simulation for parameters including ECC, CCL, MEG, DG, and TARC. To evaluate its performance even more, the design was compared with previous studies, highlighting potential areas for improvement. 2.8, 4.9, 6, 10.4, 12.5, 15.1, 19, 23, and 24.9 GHz are the nine resonance frequencies that have been observed. This makes the antenna particularly well-suited for UWB MIMO applications, including sub-6 GHz, C-band, X-band, Ku-band, and radar systems. [ABSTRACT FROM AUTHOR]

The present work introduces a novel low‐profile antenna for UWB applications through the use of a frequency‐selective surface (FSS). The FSS reflector uses a 7 × 7 array with a unit cell of 12.4 × 12.4 mm. By incorporating this periodic structure, the antenna's peak gain reaches 11 dBi, covering a UWB frequency range from 3.01 GHz to 13.5 GHz. Both FSS and UWB antennae are printed on the same type of substrate (FR4‐epoxy). The gap between the FSS layer and antenna is a half wavelength (18 mm) to obtain the best performance. The fabricated optimized antenna prototype shows a reasonable accord between numerical and experimental results. These results are compared to the existing literature designs. Overall, the proposed antenna system has reduced complexity and size, while offering a very wide bandwidth and high gain, making it a good candidate for imminent wideband and high‐gain wireless communication systems. [ABSTRACT FROM AUTHOR]

This study presents a thorough report on the development, design concept, and actual realization of multifunctional antennas (MFA). Originally developed as a clever way to counteract poor spectrum utilization through opportunistic spectrum allocation policies, MFAs are now an essential part of many contemporary wireless applications, including software-defined radio (SDR) environments and multi-standard radios (CR). Multiple radiating components on a shared substrate are used in traditional MFA realizations, which increases design constraints related to mitigating/reducing parasitic coupling and spurious impacts of the rotational arrangements needed for actuating diverse radiating elements. This study reports on a recent research contribution on the design of MFAs using a single UWB radiating element. This paper provides comparative Analysis of antennas system for Time and Frequency Division Spectrum Sensing Frameworks in Cognitive Radio Network application. In Time Division Spectrum Sensing Frameworks (TDSSF), it would consist of only one antenna that performs both sensing & communication functions. In TDSSF technique, there is discontinuity and interruption in data transmission due to sensing period in the frame. Reconfigurable antennas or Tunable antenna are used in TDSSF technique. Frequency Division Spectrum Sensing Frameworks (FDSSF) allows simultaneous spectrum sensing and data transmission over the complete spectrum for full frame duration. Multi-port antennas are used in FDSSF Technique. In FDSSF technique, one UWB antenna is used for continuously sensing and other NB antennas are used for data transmission. Theses antennas system may be used for public safety wireless communication, marine radio navigation, X-band satellite communication, mid-band 5G, ISM/WLAN/Military applications, and C-band operations [ABSTRACT FROM AUTHOR]

This study proposes a flexible MIMO antenna with improved isolation and connected ground designed on a flexible substrate that makes it compatible with various shapes and surfaces, including curved, irregular, or non-planar structures. The suggested single unit consists of a slotted rectangular radiator on the front layer with a partial ground connected to a circular stub on the other side. As well it is created on a flexible substrate (Rogers RO3003) that has a dielectric constant (εr) of 3 and a thickness of 1.52 mm. The Four copies of the single unit with orthogonal orientation are added to improve the system performance. The antenna units are connected through their ground to introduce the connected ground antenna. The size of the proposed design is compact (50 × 50 × 1.524 mm3). The simulating and testing results demonstrate that the antenna operates within a frequency range of 3–12 GHz and achieves a high isolation of ≥ 17 dB over most frequency range. The MIMO parameters and the radiation patterns are analyzed to evaluate the performance of the MIMO antenna. Finally, the four elements of the flexible antenna are fabricated and tested under flat and bending conditions. The simulation and testing results demonstrate that the suggested design exhibits excellent performance, such as broad bandwidth, high isolation, simple structure, and decreased correlation coefficient, which suggest it for the UWB applications and its flexibility allows it for integration into a wide range of devices, such as wearable technology, Internet of Things (IoT) devices, and curved surfaces of vehicles or aircraft. [ABSTRACT FROM AUTHOR]

A compact triple band notched ultra-wideband (UWB) monopole antenna is presented in this paper. Split Ring Resonator (SRR) structure is exploited in various forms like Complementary Split Ring Resonator (CSRR), Split Ring Resonator Pair (SRRP) and CSRR on Electromagnetic Band Gap (EBG) structure to produce triple band notched characteristics in UWB spectrum. The proposed antenna produces triple band notched functions with integration of all three types of SRR on primary antenna. The parametric analysis of each form of SRR is presented along with their current distribution effects on triple band notched antenna. The proposed antenna prototype is fabricated and measured results are also compared with simulated one to understand the discrepancies. The measured and simulated results are presented to investigate the band notching characteristics of suggested antenna in terms of VSWR and radiation characteristics. [ABSTRACT FROM AUTHOR]

This paper presents a reconfigurable single-filtenna system with three different modes for cognitive radio applications. The filtenna has three independent ports for Ultra Wideband (UWB), WiMAX narrowband mode, and WLAN narrowband mode, respectively. Three PIN diodes (D1, D2, and D3) are attached within the filtenna system and are used to switch between the three different modes in order to achieve frequency reconfiguration. UWB mode for sensing purposes is produced by a monopole antenna and is excited by port P1, which is controlled by D1. The desired frequencies of the narrowband communication modes are achieved by using two narrowband bandpass filters. The 5.2 GHz WLAN narrowband mode is produced by a U-shaped filter. This mode is excited by port P2 and controlled by D2. The second-order rectangular open loop resonator creates the 3.5 GHz WiMAX narrowband mode, which is excited by port P3 and controlled by D3. The simulated (measured) impedance bandwidth covers the range 2.54-12 GHz (2.54-11 GHz) for the UWB mode, with a gain value of 4.89 dB (4.5 dB). The WLAN mode covers the simulated (measured) range 5-5.36 GHz (5-5.26 GHz) with a gain value of 2.24 dB (1.92 dB), and the simulated (measured) bandwidth coverage of the WiMAX mode is 3.33-3.84 GHz (3.15-3.72 GHz) with a gain value of 3 dB (2.65 dB). The mutual coupling values are less than -22 dB for all three modes. [ABSTRACT FROM AUTHOR]

This paper presents a stepped electromagnetic bandgap(EBG) hosted on the T-shaped stepped stub with an inverted H-shaped slot etched on the ground to enhance bandwidth and improve isolation for a compact UWB-MIMO antenna developed from our previous design. The characteristic mode analysis is used to offer physical insight into the operation phenomena taking place in the evolution of antenna. The proposed antenna has a compact size of $27\times 22\times 0.8$ mm and realize bandwidth from 3.07 GHz to 11.1 GHz, keeping the isolation more than 20 dB. Key parameters evaluating the antenna performance like radiation pattern, gain, radiation efficiency above 75% and envelope correlation coefficient below 0.05 are investigated. The simulated and measured results agree well, testifying the proposed MIMO antenna is a suitable candidate for UWB applications.

Diagnosis of neural diseases can be performed using microsystems that record neural signals collected simultaneously after neural simulations. Headstage and homecage-based recording systems can be implanted on small freely-moving animals to test such system which requires miniaturized, lightweight, and high gain antennas in order for the small animals to carry them easily while also decreasing loss during data transmission. This paper proposes a $15\times $ 15 mm2 slot antenna with a $50~\Omega $ microstrip excitation line. The slot antenna is created by the addition of slots in the ground plane which is a common miniaturization method as it results in ultrawideband operating frequency. A lumped component-based model along with a 3D EM model of the modified SMA connector used for the measurement and headstage model is also developed to observe the effect on the antenna performance. The antenna achieved an operating frequency of 4.25 - 9.4 GHz and a bidirectional radiation pattern with gain ranging from 2.24 to 4.35 dBi. The proposed antenna is also circularly polarized and achieves 80.6% - 90.8% radiation efficiency over the operating BW. It can transmit a maximum of 20 dBm of power over the operating frequency without exceeding the FCC-imposed SAR limit. Based on the performance, the antenna is suitable for headstage and homecage-based neural signal recording systems with IR-UWB transmitter for high data rate transmission.

Partial discharge (PD) occurrence in high-voltage (HV) and medium-voltage (MV) power assets is a warning sign of insulation system degradation or defective manufacturing/assembly, that may cause catastrophic damage and eventually lead to the breakdown of the power equipment. Ultra-high frequency (UHF) PD measurement technology has extensively been used to monitor insulation health of the HV or MV equipment due to its high immunity against ambient noise and conducted disturbances. This paper presents experimental validation of a new design of a UHF planar rectangular microstrip antenna that can be used for PD monitoring of HV and/or MV power equipment, such as power transformers. The designed planar rectangular microstrip antenna has a compact size of 80mm $\times 70$ mm $\times 1.6$ mm. Laboratory experiments were performed to validate the antenna sensitivity to PD activity caused by insulation defects created inside an oil-filled transformer tank model. PD measurement results confirm that the proposed rectangular microstrip antenna has high sensitivity and high signal-to-noise ratio (SNR), thanks to its capability to suppress external noise disturbances, especially during the online PD monitoring. Thus, the proposed UHF antenna seems to be a promising and alternative PD sensor that can be employed in UHF PD monitoring systems of HV or MV power equipment.

Summary: A compact and novel ultrawideband (UWB) antenna integrated with Ku band for microwave imaging applications is reported. The reported antenna consists of a novel patch structure along with a tapered feed structure on top of FR‐4 substrate having a compact dimension of 16 × 22 mm2 and novel semicircular defected ground structure (SC‐DGS) etched below the substrate. The proposed antenna covers a wide impedance bandwidth of 15.07 GHz spanning from 3.51 to 18.58 GHz with a fractional bandwidth (FBW) of 136%. The intended antenna performance is analyzed for S11, peak gain, efficiency, and radiation patterns in frequency domain, and group delay, isolation (S21), and linear phase response in time domain. The simulated and measured results of reported antenna are well matched for the usage in practical portable UWB applications. More importantly, the proposed antenna system is simulated for the detection of breast cancer tissue by comparison of S21 results, current densities, and specific absorption rate with and without tumor conditions. These findings show that the radiator and the whole system work well in detecting the breast tumor. [ABSTRACT FROM AUTHOR]

In this work, a compact, edge-fed modified rectangular patch size, monopole, and ultra-wideband antenna has been presented for their good suitability to millimeter (mm) wave and upper sub-6 GHz frequency range (FR2) for next-generation (5G and beyond) communications. The patch size enhancement approach has been utilized without affecting the original size of the substrate and rectangular patch. The technique provides better impedance matching at the designed frequency of 32.5 GHz. The minimum acceptable gain for an antenna to work well is 5 dBi. The proposed design achieves peak gain of 5.43 dBi and 10.86 dBi at two resonance frequencies of 32.5 GHz and 48.12 GHz within the specified ultra-wideband (UWB). The antenna has low loss as it is fabricated on a compact Rogers RT Duroid 5880 of thickness 1.6 mm. The measured reflection coefficients are found in good agreement with the simulated one. The resultant performance parameters like radiation pattern, reflection coefficient, peak gain, and − 10 dB bandwidth reveal that the antenna performs excellently within 26 to 40 GHz with excellent impedance matching at the resonance frequency. At higher frequencies, the time domain response of the proposed design is also presented. The RLC electrical equivalent circuit of the proposed design is presented at the end and validated using ADS software. [ABSTRACT FROM AUTHOR]

This article proposes a low‐profile ultra‐wideband (UWB) antenna for breast tumor detection using the monostatic radar‐based microwave imaging (RBMI) technique. The proposed UWB antenna consists of a circular patch and ground plane along with a modified tapered feed line having a total size of 13 × 9 × 1.6 mm3. The designed antenna operates from 4 to 11 GHz based on a −10 dB reflection coefficient with a peak gain of 9.5 dBi at 4.8 GHz. Experimental validation is carried out after fabricating the prototype of the UWB antenna and the breast mimic. The measured backscattered signals are captured using the vector network analyzer (E‐5063A) by keeping the antenna at 10 mm from the breast phantom. After that, post‐processing of the measured data is done to detect the exact depth and location of the malignant tissue. The proposed antenna uses UWB band frequency of operation because it has some unique features, that is, it provides immunity to multipath fading, has a simple design, has a low cost of fabrication, and has biological friendliness. Moreover, due to the proposed antenna's resonance at a lower resonant frequency better depth of penetration is achieved in human body phantoms and the proposed antenna provides specific absorption rates (SAR) of 0.877 W/kg over 1 g of tissue at 4.8 GHz, which is an acceptable limit for SAR as per FCC guidelines. Therefore, the proposed antenna and monostatic RBMI technique are good candidates for breast tumor detection. [ABSTRACT FROM AUTHOR]

The design and analysis of a four-port multi-input multi-output (MIMO) super wideband antenna (SWB) with a metamaterial superstrate are proposed. Initially, a single antenna is constructed with a hexagonal radiator loaded with dodecagon slots along with a slotted partial ground. An impedance bandwidth of 4.1–14.7 GHz is achieved by using symmetric coplanar waveguide feeding technique and three iterations of dodecagon slot-loaded radiating element. The design is extended to a 2 × 2 MIMO antenna with dimensions 50 × 50 × 1.6 mm3. The four symmetrical SWB antennas are placed orthogonally to each other at four corners of a square-shaped FR4 substrate. A metamaterial superstrate is used above the four-port antenna to increase the antenna's performance characteristics. A 7 × 7 array of rectangular metamaterial unit cells acts as a building block for the metamaterial superstrate to improve impedance matching, enhance isolation between the elements, and boost the antenna's gain. The metamaterial unit cells are made up of three rectangular rings that are put on top of a 1.6 mm thick FR4 substrate. With a mutual coupling of (>15 dB), the antenna achieved S11 < −10 dB for an impedance bandwidth of 11 GHz. The gain enhancement of up to 1.73 dB is obtained in C and X bands using metamaterial superstrate. The antenna characteristics mainly peak gain, return loss, bandwidth, and isolation are examined. The simulated results affirm a decent deal with experimental results. [ABSTRACT FROM AUTHOR]

A4-port multiple-input multiple-output (MIMO) antenna exhibiting low mutual coupling and UWB performance is developed. The octagonal-shaped four-antenna elements are connected with a 50 Ω microstrip feed line that is arranged rotationally to achieve the orthogonal polarization for improving the MIMO system performance. The antenna has a wideband impedance bandwidth of 7.5GHz with S11 <-10 dB from (103.44%) 3.5-11GHz and inter-element isolation higher than 20 dB. Antenna validation is carried out by verifying the simulated and measured results after fabricating the antenna. The results in the form of omnidirectional radiation patterns, peak gain (≥4 dBi), and Envelope Correlation Coefficient (ECC) (≤0.01) are extracted to validate the suggested antenna performance. As well, time-domain analysis was investigated to demonstrate the operation of the suggested antenna in wideband applications. Finally, the simulated and experimental outcomes have almost similar tendencies making the antenna suitable for its use in UWB MIMO applications. [ABSTRACT FROM AUTHOR]

This paper presents a 3D-printed hemispherical lens integrated with a planar ultra-wideband (UWB) antenna. The flower-shaped stub slot UWB antenna is made of 0.8-mm FR-4. The operating frequency of the UWB covers 3.10 GHz – 11.6 GHz with a nominal gain at zero degrees of 1.74 dBi. To enhance the UWB antenna’s high-gain radiation, a 3D-printed additive hemispherical lens is designed and fabricated from acrylonitrile butadiene styrene (ABS). The electrical properties, i.e., relative permittivity and loss tangent, of ABS are 2.66, and 0.003, respectively. Four different lens radii (8 mm, 10 mm, 12 mm, and 14 mm) are chosen to investigate the gain of the antenna. In all four cases, the 3D-printed lens is fixed in place in front of the UWB antenna with an optimum gap of 3 mm chosen to reduce the wave reflection between the lens and source antenna. Based on the measurement results, the reflection coefficient, $S_{11}$ , of four conditions still covers the UWB frequency range. The nominal gain at zero-degree values for lens radii of 8 mm, 10 mm, 12 mm, and 14 mm are 3.43 dBi, 4.22 dBi, 4.73 dBi, and 5.18 dBi, respectively. The proposed additive 3D-printed dielectric lens antenna also offers many advantages, i.e., ease of design and assembly, low-cost fabrication, and size reduction for high-gain antennas. Furthermore, the high-gain antenna provides a narrow half power beamwidth, which can be implemented to increase the resolution of the imaging system.

Ultra Wideband (UWB) technology is an unmodulated wireless digital communication system that uses an extremely short duration pulse to transmit information bit. Because of this pulse, the UWB system needs a very wide bandwidth. Federal Communication Commission (FCC) has regulated the 3.1 – 10.6 GHz frequency spectrum for UWB. Since FCC released this frequency, many research in telecommunication have been done on UWB systems. One of them is a development of an Antenna that is suitable for UWB devices. UWB antenna characteristics require FCC band, omnidirectional radiation pattern, and compact size. In order to meet these needs, an antenna with a simple structure in the form of a monopole patch antenna with a similar patch size and ground width has been designed. The antenna is built on an FR4 – epoxy substrate material, with 4.4 dielectric constant and 1.6 mm thickness. The antenna feeding structure consists of two 100 Ω and 50 Ω lines with a wideband impedance matching scheme using tapered side and tapered transformers. The antenna design and optimization processes are conducted using electromagnetic simulation software, and measurements are carried out in an anechoic chamber. Simulation and measurement results show good agreement, and the antenna can work at frequencies 3.5 - 11.3 GHz with a gain of 1.5 – 3.25 dBi and stable omnidirectional radiation patterns. The antenna has dimensions of 27 × 8 × 1.6 mm, which are smaller than the antenna reported in the last research and suitable to be applied on various UWB devices.

The objective of this paper is to develop a wearable circular UWB MIMO antenna array, consisting of four elements, that is capable of detecting and locating tumor cells within a heterogeneous breast phantom. The antenna element operates within a bandwidth from 2.4 GHz to 10.6 GHz when FR4 is used as the substrate, and extends from 2.57 GHz to 12.6 GHz when a Dacron fabric is used instead. The antenna is fabricated and measured, yielding highly similar results to the simulated outcomes. In the suggested detection system, one antenna is used for transmission, while the other antennas receive the transmitted signal. The employed antenna demonstrates gains of 5.49 dBi, 9.87 dBi, 11.9 dBi, and 14.7 dBi at resonant frequencies of 2.84 GHz, 3.87 GHz, 5.83 GHz, and 8.24 GHz, respectively, when a Dacron fabric is used as the substrate. Moreover, the proposed antenna exhibits a flexible shape with minimal vertical and horizontal bending effects across the entire operating frequency band. The antenna has a compact size of 42.85 × 42.85 mm2 and is printed on an FR4 substrate with a dielectric constant of 4.5 and a thickness of 1.6 mm for testing purposes. The S-parameters of the suggested system can effectively identify and precisely locate small tumors. Furthermore, the SAR findings indicate that the amount of power absorbed by the breast phantom tissues complies with the IEEE standards, thus confirming the suitability of the recommended antenna for the early detection and localization of breast cancer. [ABSTRACT FROM AUTHOR]

Ultra-wideband (UWB) technology is widely used in many communication scenarios. However, narrowband systems can easily interfere with the UWB system, which generates multipath fading. In order to solve these interferences and meet the design requirements of high isolation of multiple-input multiple-output (MIMO) antennas, two MIMO antennas with double-notch structures are designed. Firstly, two U-shaped slots are etched on the radiating patch and feeder to achieve notch characteristics in WiMAX and ITU bands. Using this antenna element, a two-element antenna is put symmetrically in parallel, and two rectangular branches are loaded to improve the isolation. The size is 0.57λ × 0.32λ × 0.013λ (at 2.5 GHz). Then, a four-element antenna is designed to meet the requirements for another application; here, each element is placed orthogonally to each other, and the isolation is improved through loading a cross-shaped branch in the middle of these elements. The size is 0.57λ × 0.57λ × 0.013λ. Both antenna samples are tested to verify the design. Measurement results show that the working bandwidth is 2.45–14.88 GHz and 2.14–14.95 GHz, the isolation is greater than 17 and 20 dB, and the peak gain is 5.7 and 5.9 dBi for the two- and four-element MIMO antenna, respectively. Compared to the references, the designed antennas have a wider bandwidth and a higher gain and radiation efficiency. They are well-suited for diverse wireless applications. [ABSTRACT FROM AUTHOR]

This paper presents a novel multi-objective naked mole-rat (MONMR) algorithm to optimize two printed monopole patch antenna structures for ultrawideband (UWB) applications. The design includes basic-ultrawideband and triple band-notch characteristic antennas. The performance of MONMR is evaluated for two objectives: minimize pass-band signal reflection and maximize the gain of the antenna. In resultant, MONMR provided multiple optimum antenna designs instead of a single antenna design by mapping solutions to the Pareto-front (PF) boundary in the objective space. The simulated results matched with the experimental results and hence MONMR has proved to be an effective approach in the field of electromagnetics. Moreover, the obtained PF designs are better than the reported UWB antennas in terms of the gain and reflection coefficient. [ABSTRACT FROM AUTHOR]

In this article, a Metallic Via(M-Via) based eight-port compact Ultra-Wideband (UWB) MIMO antenna is introduced for IoT applications. In proposed UWB MIMO antenna design, we employed a simple Metallic Via(M-Via) integration technique to achieve UWB bandwidth with a compact size of 54 × 54 mm 3 . The important antenna parameters, such as reflection coefficient, mutual coupling, the Peak gain, radiation pattern, and radiation efficiency, are analysed. In addition, MIMO parameters such as ECC, DG, TARC, and CCL are experimentally analysed. Also, the proposed antenna is demonstrated in a real-time environment. [ABSTRACT FROM AUTHOR]

Proposal and comprehension of spur line embedded frequency notched Ultrawideband antenna is projected in this paper. The performance of the antenna is enhanced by using square shaped metamaterial. Quarter-wavelength long spur line (lines) on the feeding microstrip line of UWB antenna backs a notch-filtering action to provide single/double/triple notch (notches) within the UWB spectrum of the antenna. The planned method is very simple and radiator independent. The conventional monopole antenna is loaded with square shaped metasurface (MS) to enhance the performance of the antenna. With and without metamaterial loaded single, double and triple spurline embedded microstrip fed circular monopole antennas are separately designed, fabricated and measured. All the deliberate models are fabricated and considered for measurement of impedance and radiation characteristics. Measured results show very good consistency with that of results obtained from full wave simulation. [ABSTRACT FROM AUTHOR]

Abstract In this article a low profile asymmetrical slotted Ultra-Wide Band (UWB) antenna is proposed for Wireless Body Area Networks (WBANs) applications. The antenna was fabricated using Printed Circuit Boards (PCBs). An improved radiation pattern was obtained with an optimized patch shape of the antenna that broadens the bandwidth and lowers the antenna’s profile. The proposed antenna is simulated in HFSS and CST Simulator, and the proposed antenna is fabricated on FR4 substrate with the reduced ground plane. In frequency ranges from 2.50 to 10.97 GHz simulation as well as measured results show that the reflection coefficient (S 11) of the antenna is below − 10 dB and increased impedance bandwidth of 126%. The proposed antenna has desired radiation pattern and gain for wearable application. The wearable performance of proposed antenna on chest, leg, and the arms of the human body is analyzed with Specific Absorption Rate (SAR). The maximum value of the SAR is 0.785 W/Kg which is less than threshold value of 1.6 W/kg. The time-domain behavior of proposed antenna is investigated with the time domain parameters such as Group delay, Fidelity factor and Mean realized gain. The time domain results are evident for the proposed antenna is capable of pulse signal transmission and reception.

In this paper, a miniaturized textile microstrip antenna is proposed for wireless body area networks (WBAN). The ultra-wideband (UWB) antenna used a denim substrate to reduce the surface wave losses. The monopole antenna consists of a modified circular radiation patch and an asymmetric defected ground structure, which expands impedance bandwidth (BW) and improves the radiation patterns of the antenna with a small size of 20 × 30 × 1.4 mm3. An impedance BW of 110% (2.85–9.81 GHz) frequency boundaries was observed. Based on the measured results, a peak gain of 3.28 dBi was analyzed at 6 GHz. The SAR values were calculated to observe the radiation effects, and the SAR values obtained from the simulation at 4/6/8 GHz frequencies followed the FCC guideline. Compared to typical wearable miniaturized antennas, the antenna size is reduced by 62.5%. The proposed antenna has good performance and can be integrated on a peaked cap as a wearable antenna for indoor positioning systems. [ABSTRACT FROM AUTHOR]

An ultra-wideband (UWB), geometrically simple, compact, and high-gain antenna with a WLAN notch band is presented for future wireless devices. The antenna is printed on the top side of the Rogers RT/Duroid 5880 substrate and has a small dimension of 10 mm × 15 mm × 0.254 mm. The primary radiator of the proposed coplanar waveguide-fed monopole antenna is comprised of a rectangular-shaped structure initially modified using a slot, and its bandwidth is further enhanced by loading a Y-shaped radiator. As a result, the antenna offers a –10 dB impedance matching bandwidth of 11.55 GHz ranging from 3–14.55 GHz, covering globally allocated C-, S-, and X-band applications. Afterward, another rectangular stub is loaded in the structure to mitigate the WLAN band from the UWB spectrum, and the final antenna offers a notched band spanning from 4.59 to 5.82 GHz. Moreover, to validate the simulated results, a hardware prototype is built and measured, which exhibits good agreement with the simulated results. Furthermore, the proposed work is compared to state-of-the-art antennas for similar applications to demonstrate its design significance, as it has a compact size, wider bandwidth, and stable gain characteristics. [ABSTRACT FROM AUTHOR]

The demand for high-speed wireless communication systems has led to the development of ultrawide-band (UWB) antennas with a compact size and high performance. In this paper, we propose a novel four-port multiple-input multiple-output (MIMO) antenna with an asymptote-shaped structure that overcomes the limitations of existing designs for UWB applications. The antenna elements are placed orthogonally to each other for polarization diversity, and each element features a stepped rectangular patch with a tapered microstrip feedline. The unique structure of the antenna significantly reduces its dimensions to 42 × 42 mm2 ( 0.43 λ × 0.43 λ @   3.09 GHz ), making it highly desirable for use in small wireless devices. To further enhance the antenna's performance, we use two parasitic tapes on the ground plane at the back as decoupling structures between adjacent elements. The tapes are designed in a windmill shape and a rotating extended cross shape, respectively, to further improve the isolation. We fabricated and measured the proposed antenna design on a single-layer substrate (FR4) with a dielectric constant of 4.4 and a thickness of 1 mm. The measured results show that the impedance bandwidth of the antenna is 3.09–12 GHz, with an isolation of −16.4 dB, an envelope correlation coefficient (ECC) of 0.02, a diversity gain (DG) of 9.991 dB, an average total effective reflection coefficient (TARC) of −20 dB, an overall group delay value less than 1.4 ns, and a peak gain of 5.1 dBi. Although there may be some antennas that have better performance in one or two specific aspects, our proposed antenna has an excellent trade-off among all the antenna characteristics including bandwidth, size, and isolation. The proposed antenna also exhibits good quasi-omnidirectional radiation properties, making it well-suited for a range of emerging UWB-MIMO communication systems, particularly in small wireless devices. In summary, the compact size and ultrawide-band capabilities of the proposed MIMO antenna design, coupled with its improved performance compared to other recent UWB-MIMO designs, make it a promising candidate for 5G and next-generation wireless communication systems. [ABSTRACT FROM AUTHOR]

This work introduces the design and the fabrication of high gain, ultra wideband Antipodal Vivaldi Antenna (AVA) with dual band-notches behavior. The antenna is designed using 70×55×1 mm3 FR4-dielectric substrate with er=4.4. The proposed antenna satisfies the Ultra-Wide Band (UWB) characteristics and has maximum gain of 9.3 dB. The spurline slot technique is used to achieve two band-notches. The first band-notch is obtained at worldwide interoperability for microwave access (WiMax) band, while, the second band-notch is obtained for Wireless Local Area Network (WLAN) IEEE systems in order to reduce the electromagnetic interference in these bands. By etching out two spurline slots from the transmission line structure, high band-notches characteristics are achieved. Moreover, the current distribution in the antenna wings has no effect, as well as the radiation pattern shapes, and high gain is achieved. The simulation and the measurement results have a high level of agreement. [ABSTRACT FROM AUTHOR]

In this article, a single-layer frequency selective surface (FSS)-loaded compact coplanar waveguide (CPW)-fed antenna is proposed for very high-gain and ultra-wideband applications. At the initial stage, a geometrically simple ultra-wideband (UWB) antenna is designed which contains CPW feed lines and a multi-stub-loaded hexagonal patch. The various stubs are inserted to improve the bandwidth of the radiator. The antenna operates at 5–17 GHz and offers 6.5 dBi peak gain. Subsequently, the proposed FSS structure is designed and loaded beneath the proposed UWB antenna to improve bandwidth and enhance gain. The antenna loaded with FSS operates at an ultra-wideband of 3–18 GHz and offers a peak gain of 10.5 dBi. The FSS layer contains 5 × 5 unit cells with a total dimension of 50 mm × 50 mm. The gap between the FSS layer and UWB antenna is 9 mm, which is fixed to obtain maximum gain. The proposed UWB antenna and its results are compared with the fabricated prototype to verify the results. Moreover, the performance parameters such as bandwidth, gain, operational frequency, and the number of FSS layers used in the proposed antenna are compared with existing literature to show the significance of the proposed work. Overall, the proposed antenna is easy to fabricate and has a low profile and simple geometry with a compact size while offering a very wide bandwidth and high gain. Due to all of its performance properties, the proposed antenna system is a strong candidate for upcoming wideband and high-gain applications. [ABSTRACT FROM AUTHOR]

This article presents an ultra-wideband (UWB) monopole antenna with triple band notch characteristics. The proposed antenna consists of an octagonal patch, fed with a 50 Ω line, which occupies a compact size of 40 mm × 29 mm (0.36λ × 0.26λ, λ is computed using 2.7 GHz frequency) and resonances at a relatively low frequency (2.94 GHz). Specifically, an L-shaped stub, an inverted C-shaped slot, and a pair of U-shaped resonating structures are introduced into the design, which allow antenna to generate three band notches at 3.22–3.83 GHz, 4.49–5.05 GHz and 7.49–8.02 GHz, corresponding to WiMAX band, Indian national satellite (INSAT) band, and X-band satellite frequencies, respectively. In the center of the notched band, the antenna has lower efficiency and gain, essentially indicating that the antenna has good interference rejection performance. To evaluate its performance, the proposed antenna has been fabricated and measured, and the relevant functional parameters, such as S-parameters, voltage standing wave ratio (VSWR) and radiation property, have been studied. [ABSTRACT FROM AUTHOR]

In this work, two elements and four elements compact UWB MIMO antennas are designed and fabricated. A printed circular disc with five circular slots is selected in this work due to its UWB performance and compact size for the MIMO antenna system. CST software is used in the simulation process. Measured S parameters show that the MIMO antennas work well from 3 GHz up to 20 GHz (maximum working frequency of the measurement instruments). The two elements MIMO antenna has a size of 70 × 40 mm2 meanwhile the four elements MIMO antenna has a size of 70 × 70 mm2. Measurement results show that the isolation among the antenna elements is higher than 20 dB. The envelope correlation coefficient, diversity gain, channel capacity loss, mean effective gain and total active reflection coefficient are studied in this paper. Simulations results show that the MIMO antennas have a satisfactory performance up to 50 GHz. [ABSTRACT FROM AUTHOR]

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This paper discusses an elliptical ultrawideband (UWB) antenna and a dual-band UWB notch antenna. To achieve a UWB bandwidth, two corner cuts are etched into the rectangular slot on the partial ground plane. An inverted-U-shaped and conductor-shaped resonator are utilized to achieve dual-band notch characteristics on a partial ground plane. The suggested antenna has an overall dimension of 24 × 32   mm 2 . The suggested UWB antenna has a gain of 4.9 dB, a bandwidth of 2.5–11 GHz, a linear phase response, a group delay of less than 1 ns, and a steady radiation pattern. The suggested UWB notch rejects WLAN and ITU bands from 5.2–5.7 GHz and 7.2–8.5 GHz, respectively, with an impedance bandwidth of 2.5–11 GHz. The UWB notch antenna features a linear phase, a group delay of less than 1 ns, and a stable radiation pattern. [ABSTRACT FROM AUTHOR]

In this communication, the design and analyses of the novel printed ultra wide band ring monopole antenna is presented. The recommended antenna has a pretty small size of 20 x 26 x 1.6 mm3 which is printed on the FR4 dielectric material which has the dielectric constant of 4.4 ad loss tangent of 0.02. The general geometry of the radiating part of the antenna is composed of the circular ring. The antenna has a defected ground structure which has the circular corner points. The antenna feed is placed in asymmetrical position with respect to the x-axis as a the microstrip line. The findings obtained by examining the general antenna performance criteria are presented in a systematic way. The results indicate that the proposed antenna has a suitable performance parameters at the UWB frequency range.

This communication describes the development and assessment of the genuine Antipodal Vivaldi MIMO antenna operating in the ultra-wideband spectrum. FR4 dielectric material, which is widely used in antenna designs and has characteristic features, is selected and used as a dielectric. The single antenna component has two asymmetric flares obtained with different parameters, and it also has a rectangular ground plane combined with a bottom flare. In the MIMO configuration, the single-antenna is built in a rotationally orthogonal way to generate a four-port system with the dimensions of 45 × 45 × 1 mm3. The vertical and horizontal stubs are added to the ground flare to obtain a common ground structure and increase the performance of the novel antenna design. It has a bandwidth of approximately 9 GHz, which starts from 2.85 GHz and ends at 11.8 GHz. The antenna has reasonable gain values and a high isolation value between the elements in the operation range. In this context, it is foreseen that the developed structure can be utilized in distinct multiport UWB applications. [ABSTRACT FROM AUTHOR]