In this article, high-gain ultra-wideband (UWB) monopole antenna is presented. The UWB monopole antenna is a semicircular-shaped antenna with a semicircular slot at the top side. The bottom plane ...consists of partial ground with triangular and rectangular slotted structures to improve the impedance bandwidth of the proposed antenna. In order to enhance gain, a 6×6 metallic reflector (FSS) is placed below the antenna. The performance of the offered design is validated experimentally. The simulated results show resemblance with the measured results. The antenna resonates for the UWB ranging from 3 to 11 GHz. Moreover, the integration of FSS improves the average gain by 4 dB, where peak gain obtained is 8.3 dB across the UWB. In addition, the reported unit cell having dimension of 0.11λ×0.11λ gives wide bandwidth (7.2 GHz) from 3.3 GHz to 10.5 GHz. The performance of the proposed antenna determines its suitability for the modern day wireless UWB and GPR applications.
This work presents an eight element array antenna with single layer frequency selective surface (FSS) to obtain high gain. The eight elements are fed by single port. The FSS consists of 14 ...<inline-formula> <tex-math notation="LaTeX">\times </tex-math></inline-formula> 6 unit cells with one unit cell size is 5 <inline-formula> <tex-math notation="LaTeX">\times </tex-math></inline-formula> 5 mm 2 having wideband behavior. The antenna uses Rogers RT Duroid 5880 substrate and giving very wide bandwidth from 20 GHz to 65 GHz, covering millimeter wave 5G bands (including 28 GHz, 38 GHz and 60 GHz). The designed FSS is showing stop band transmission characteristics below −10 dB threshold from 25 GHz to 42 GHz and 59 GHz to 61 GHz. The eight element antenna integrated with the FSS reflector, which results an improvement in the gain level from 12 dB to 15 dB at 28 GHz, from 10 dB to 12 dB at 38 GHz, and from 9.5 to 11 dB at 60 GHz. The dimensions of the antenna are 65 <inline-formula> <tex-math notation="LaTeX">\times </tex-math></inline-formula> 27 <inline-formula> <tex-math notation="LaTeX">\times </tex-math></inline-formula> 0.857 mm 3 . The proposed antenna shows stable gain and directional radiation patterns. The simulation findings are experimentally confirmed, by testing the fabricated prototypes of the proposed antenna system.
This paper presents a 10-ports, hybrid multiple-input multiple-output (MIMO) antenna system for 5G Smartphone applications. The proposed antenna system comprises two types of antenna modules: (1) ...multi-band module consists of two identical multiband antenna elements, each antenna element in this module covers the 2G bands (GSM 850/900/1800/1900 MHz), 3G band (UMTS 2100 MHz) and 4G bands (LTE 2300/2500), and (2) single-band module consists of eight identical L shape elements, each antenna element in this module covers the C-band (3400-3600 MHz) for 5G mobile application. The overall dimensions of the proposed antenna system are <inline-formula> <tex-math notation="LaTeX">150\times 80\,\,mm^{2} </tex-math></inline-formula>. The proposed antenna system is fabricated and tested. Experimental results show reflection coefficients better than -6 dB and -10 dB for multi-band and single-band modules, respectively, with high isolation levels between the antenna elements in both modules. Moreover, the measured envelop correlation coefficients (ECC) is well below 0.3 and 0.1 for the proposed multi-band and single-bands modules, respectively. In addition, single antenna elements in both modules show good radiation characteristics with maximum peak gain between 2 dBi and 4 dBi. Finally, 43 bps/Hz channel capacity is achieved in the single-band module. With these characteristics, the proposed antenna system can be a good candidate in the modern mobile communication systems.
This paper presents the design of three types of dual band (2.5 & 5.2 GHz) wearable microstrip patch antennas. The first one is based on a conventional ground plane, whereas the other two antennas ...are based on two different types of two-dimensional electromagnetic band gap (EBG) structures. The design of these two different dual-band EBG structures using wearable substrates incorporates several factors in order to improve the performance of the proposed conventional ground plane (dual band) wearable antenna. The second EBG with plus-shaped slots is about 22.7% more compact in size relative to the designed mushroom-like EBG. Subsequently, we have demonstrated that the mushroom-like EBG and the EBG with plus-shaped slots improve the bandwidth by 5.2 MHz and 7.9 MHz at lower resonance frequencies and by 33.6 MHz and 16.7 MHz at higher resonance frequencies, respectively. Furthermore, improvements in gain of 4.33% and 16.5% at a frequency of 2.5 GHz and improvements in gain of 30.43% and 4.57% at 5.2 GHz have been achieved by using the mushroom-like EBG and EBG with plus-shaped slots, respectively. The operation of the conventional ground plane antenna is investigated under different bending conditions, such as wrapped around different rounded body parts. The proposed conventional ground plane antenna is placed over a three-layered (flat body phantom (chest)) and four-layered (rounded body parts) tissue models, and a thorough SAR analysis has been performed. It is concluded that the proposed antenna reduces SAR effects (<2 W/kg) on the human body, thereby making it useful for numerous critical wearable applications.
In this paper a triple-band dielectric resonator antenna (DRA) is designed using a 0.8 mm thicker Arlan FR-25 substrate, having relative dielectric constant of 3.58 and loss tangent of 0.0035. The ...antenna works in three unique frequency bands of 15, 16.3 and 18.5 GHz, lying in the sub-20 GHz spectrum. A stack of ten radiating elements of AR100 material, are installed at the centre of the proposed antenna structure. The DRA is excited through an elliptical aperture in the metallic plane via a 50 Ohm microstrip feed line, etched on the rear side of the Arlan FR-25 substrate. Stacked parasitic elements are incorporated around the central radiating element for achieving enhanced gain. The proposed DRA gives satisfactory gain and fractional bandwidth of (8.06 dB, 12%), (10.7 dB, 3%) and (7.03 dB, 2.73%) at 15, 16.3 and 18.3 GHz bands, respectively. The simulation results of the DRA are compared and validated using three different analysis techniques i.e., FIT (Finite Integration Technique), FDTD (Finite Difference Time Domain) Method and FEM (Finite Element Method). The designed antenna can be used for future fifth generation (5G) systems (15 GHz), internet of things (IoT) based device-to-device (D2D) communication and satellite applications (16.3–18.3 GHz).
The increasing demand for wireless communication in wearable devices has led to the need for wearable antennas with a low profile, flexibility, robustness, low SAR, and acceptable on-body performance ...for WBAN applications. This study presents a low-profile dual-band wearable antenna for WBAN applications operating at 2.45 and 5.8 GHz. The antenna is integrated with a <inline-formula> <tex-math notation="LaTeX">3\times3 </tex-math></inline-formula> artificial magnetic conductor array to reduce backward radiation and improve performance when worn on the human body. It is designed and fabricated on a 2 mm-thick flexible felt substrate with a relative permittivity of 1.3 and loss tangent of 0.044. A 0.17 mm-thick superconductive shieldit material is used as conductive material for the antenna and AMC array. The proposed antenna and AMC array have overall volumes of <inline-formula> <tex-math notation="LaTeX">0.41\lambda _{0} \times 0.45\lambda _{0} \times 0.016\lambda _{0} </tex-math></inline-formula> and <inline-formula> <tex-math notation="LaTeX">0.83\lambda _{0} \times 0.83\lambda _{0} \times 0.016\lambda _{0} </tex-math></inline-formula>, respectively. Results indicate that the AMC structure enhances the antenna's gain, radiation efficiency, and bandwidth. The use of AMC reduced the SAR by greater than 98% for 1 and 10 g of human tissue at 2.45 and 5.8 GHz. The proposed design is suitable for WBAN applications due to its low profile, flexibility, robustness, low SAR, and acceptable on-body antenna gain and bandwidth.
We analyzed smut fungi (
Ustilaginales
) parasitizing nine poaceous hosts from three districts (Shangla, Mansehra, and Dir Upper) of Khyber Pakhtunkhwa Province, Pakistan. Eight taxa were identified ...in two genera using both morphological and molecular techniques by amplifying ITS and LSU regions. We describe
Ustilago pseudosyntherismae
sp. nov. on
Digitaria sanguinalis
and
Dactylis glomerata
as new to science and
U. neocopinata
as a new record for Pakistan. We provide updated distribution records for six smut species viz.
U. maydis
,
U. tritici
,
Sporisorium cruentum
,
S. moniliferum
,
S. reilianum
, and
S. schweinfurthianum
.
Veloporphyrellus latisporus is proposed as a new species based on morphological characters and supporting molecular data from the ITS and LSU regions of the nuclear DNA. The new species is ...characterized by its red to reddish brown granulose pileus and comparatively broader basidiospores. A key to the species of Veloporphyrellus is provided. This is the first report of any Veloporphyrellus species from Pakistan.
This study designed and analyzed an artificial magnetic conductor (AMC)-based fabric antenna for body-centric communication. The antenna was made of felt and had a loss tangent of 0.044 and relative ...permittivity of 1.3. The proposed antenna was built to function in the frequency band centered at 2.45 GHz, widely used in wireless communication devices. The antenna's performance was evaluated using the electromagnetic simulation software CST MWS. A 50 Ω SubMiniature version connector was used to excite the proposed antenna. A 2 × 2 AMC array was integrated into the antenna below it to improve its performance in terms of radiation efficiency, gain, and backward radiation reduction. The antenna and AMC array were fabricated on flexible fabric substrates. The total volume of the AMC-integrated antenna is 0.55λ 0 × 0.55λ 0 × 0.016λ 0 . It was demonstrated that adding an AMC array enhanced the radiation properties of the antenna and significantly decreased its back lobes. The on- and off-body maximum gains of the AMC-integrated antenna are (≥ 4.11 dBi) and 5.23 dBi, respectively. Furthermore, employing the AMC array, a significant reduction in the specific absorption rate value, which is (≤ 0.43 W/kg) for human body tissue chest/back and (≤ 0.75 W/kg) for human body tissue arm, was obtained, ensuring safety for human use. The simulated and measured results were in agreement. The tested on- and off-body radiation efficiencies in the frequency band centered at 2.45 GHz is (>67%) and (>83%), respectively. The proposed antenna can potentially be used in various applications such as healthcare monitoring, wearable electronics, and Internet of Things (IoT) systems, where reliable and efficient communication is required in a body-centric environment.
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