Conventional Patch Research Articles

A novel wideband dual‐polarized heptagonal magnetoelectric dipole antenna loaded with inverted L‐shaped structures

AbstractA novel dual linearly‐polarized magnetoelectric (ME) dipole antenna with wide bandwidth is presented in this letter, where two orthogonally placed Г probes are utilized to realize dual polarizations. In particular, four heptagonal patches are first adopted in lieu of the four conventional rectangular patches to obtain a wider bandwidth. In the sequel, four inverted L‐shaped parasitic elements are loaded on the periphery of the four patches to further enhance the bandwidth of ME dipole antenna. A prototype is fabricated and measured to verify the properties of the proposed antenna. The simulated and measured results show that the overlapped 10 dB bandwidth of 99.2% can be achieved ranging from 1.2 to 3.56 GHz, and the available peak gain can be as high as 12 dBi. Meanwhile, its cross‐polarization level (CRPL) is lower than −22 dB, and the isolation between the two ports is larger than 20 dB across the operating frequency.

An Analytical Framework of Multisector Rectenna Array Design for Angular Misalignment Tolerant RF Power Transfer Systems

A design procedure is presented for an angular misalignment-tolerant multisector rectenna array used as a wireless energy harvesting (WEH) system. The proposed analytical framework derives constraints on the synthesized harvested dc power pattern of the rectenna element as a solution to completely mitigate the angular misalignment. The derived constraints determine the optimal number of sectors required to ensure uniform harvesting capability across the entire azimuth plane. This is analytically verified for a conventional patch antenna used in the rectenna element of the multisector WEH system. The design constraints give <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$N=8$ </tex-math></inline-formula> and 12 sectors the optimal solution for single patch and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2 \times 1$ </tex-math></inline-formula> patch array rectenna. Furthermore, a new multilayer wide-beam rectenna is proposed at 5.8 GHz requiring <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$N=6$ </tex-math></inline-formula> sectors to mitigate the angular misalignment with 36.5% size reduction when compared with the conventional patch WEH system. The prototype of the WEH systems using the conventional patch rectenna and the proposed rectenna is fabricated and measured. The measurement results corroborate the analytical and simulation results validating the capability of the proposed framework to achieve uniform energy harvesting in the entire azimuth plane.

A Broadband Circularly Polarized Single-Layer Metasurface Antenna Using Characteristic-Mode Analysis

In this work, we propose a low-profile single-layer coplanar waveguide (CPW)-fed metasurface (MTS) antenna with broadband circular polarization (CP) radiation. With the help of characteristic-mode analysis (CMA), a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\textbf {3}\times \textbf {4}$ </tex-math></inline-formula> MTS is analyzed to reveal the useful modes supported by the structure. Consequently, two modes with orthogonal current distribution, broadside radiation, and nearly <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mathrm{90}^{\circ} $ </tex-math></inline-formula> phase difference over a wide frequency band are chosen as operation modes. Moreover, the modal near field of the aforementioned modes shows that, unlike conventional microstrip patches, the entire proposed MTS supports two kinds of extraordinary TM modes, namely, e-TM30 and e-TM04. Accordingly, a rotated CPW feeding line is used to excite the two modes without adding an extra layer as reported in the literature, making the design simpler and easier to manufacture. Based on that, a low profile antenna of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\textbf {0.058}\lambda _{0}$ </tex-math></inline-formula> has been designed and fabricated. The measured results show an impedance bandwidth (IBW) of 25% (4.870–6.26 GHz), 3 dB axial ratio (AR) band of 19.42% (5.30–6.44 GHz), and a maximum gain of 8 dBi.

Analysis of On-Antenna Power Combining for Realization of Pattern-Reconfigurable Multifeed Microstrip Antennas

This article explores an on-antenna power combining concept for multifeed microstrip antennas. We incorporated different radiation modes of multifeed antennas, thereby optimally exploiting the given space of a single radiator. The analytical cavity model is revisited to facilitate analysis of the on-antenna power combining mechanism in planar topologies. The analytical modeling is first aimed to apply to conventional patch structures and offers an in-depth design methodology. As the analytical method is facing limitations in irregular-shaped antennas we proposed a reliable and computationally cheap numerical method based on the eigenvalue analysis of the scattering matrix. The proposed method can be used to extract the optimum excitation and impedance of each port of resonant-type multifeed antennas. Due to the proposed numerical method, one can examine the excitation vector and the active impedance values for different radiation modes of multifeed antenna concurrently. Next, the reliability of the solutions of the proposed numerical method is evaluated against the analytical solutions through some examples. A multifeed structure not only can furnish on-antenna power combining but also assist with tailoring reconfigurable antennas. Finally, a practical planar radiator topology featuring multifeed excitations exhibiting a high-gain reconfigurable antenna with sum and difference patterns is devised.

Dual polarization and mutual coupling improvement of UWB MIMO antenna with cross shape decoupling structure

A simple, compact MIMO antenna that operates in the UWB frequency band is presented in this paper. The proposed antenna consists of four elements where the shape of the radiators derived from series modifications of a conventional rectangular patch antenna. Radiators are placed orthogonally to each other to achieve the dual polarization operation and cross shape Defected Ground Structure (DGS) is inserted in the ground plane to improve decoupling between the antenna elements. The designed model was fabricated on FR-4 substrate with dimensions of 48 × 44 × 1.6 mm3 and measurements were performed to validate the simulated results. The fractional bandwidth reaches 112% from 3.1 GHz to 11 GHz with reflection coefficient less than -10 dB and mutual coupling between antenna elements is less than -20 dB. The antenna has a stable radiation pattern, and low gain variation. In addition, the time domain characteristics and diversity performance indicators were evaluated and compared with the standard values. The miniaturized dimensioning of the antenna along with the good performance metrics indicates that the proposed antenna can be used in various UWB applications such as portable handheld devices.

Supramolecular Dissolving Microneedle Patch Loading Hydrophobic Glucocorticoid for Effective Psoriasis Treatment.

Glucocorticoid-based creams are commonly used for treatments of psoriatic skin lesions while showing poor permeation because the thickened stratum corneum severely limits drug absorption. Although dissolving microneedle (DMN) patches have been employed in treating skin disease by virtue of their direct target to the lesion site, conventional DMN patches are generally fabricated from the water-soluble matrix, making them difficult to efficiently encapsulate hydrophobic glucocorticoids. Here, we develop a mechanically robust supramolecular DMN composed of hydroxypropyl β-cyclodextrin (HPCD) to effectively and uniformly load triamcinolone acetonide (TA). The TA-loaded HPCD DMN (TAMN) exhibits excellent mechanical performance that can easily pierce the thickened psoriasis lesions and deliver TA efficiently. Owing to the increased water solubility and bioavailability of TA after inclusion into HPCD, TAMN shows a superior in vitro inhibitory effect on immortalized human keratinocyte (HaCaT) cells. Importantly, the administration of TAMN twice a week effectively alleviates psoriatic signs and reduces the expression of Ki67, IL-23, and IL-17 in the ear lesions of imiquimod-induced psoriasis-like mice. This supramolecular DMN provides a promising strategy for the efficient treatment of psoriasis and other skin diseases, greatly broadens the applications of supramolecular materials in transdermal drug delivery, and widens the range of drugs in DMNs.

Ultrabroadband RCS Reduction and Gain Enhancement of Patch Antennas by Phase Gradient Metasurfaces

In this letter, a novel design based on phase gradient metasurfaces (PGMs) is proposed to reduce the radar cross section (RCS) and enhance the gain of patch antennas. The PGM unit consists of a cross-dipole and three square-dipole rings. The proposed antenna is composed of a conventional patch radiator and four surrounding sequential-rotated PGMs. On the one hand, an ultrabroadband RCS reduction is achieved due to the PGMs phase discontinuity deflects the signal away from the specular direction by the PGMs. On the other hand, a gain enhancement is achieved because the enlarged equivalent radiation aperture owing to the coupling effect between the PGMs and the patch. A prototype operating at Ku band is designed, fabricated, and measured. It is demonstrated that an over 6 dB RCS reduction is obtained from 9.31 to 28.22 GHz, and an average 1.5 dB gain enhancement is obtained within the working band of 14.2–15.5 GHz, which can be used in stealth platforms.

Commonly Used Therapeutics Associated with Changes in Arousal Inhibit GABAAR Activation.

GABAA receptor-positive modulators are well-known to induce sedation, sleep, and general anesthesia. Conversely, GABAA receptor negative allosteric modulators (GABAARNAMs) can increase arousal and induce seizures. Motivated by our studies with patients with hypersomnia, and our discovery that two GABAARNAMs can restore the Excitation/Inhibition (E/I) balance in vitro and arousal in vivo, we chose to screen 11 compounds that have been reported to modulate arousal, to see if they shared a GABA-related mechanism. We determined modulation with both conventional and microfluidic patch clamp methods. We found that receptor activation was variably modulated by all 11 compounds: Rifampicin (RIF), Metronidazole (MET), Minocycline (MIN), Erythromycin (ERY), Ofloxacin (OFX), Chloroquine (CQ), Hydroxychloroquine sulfate (HCQ), Flumazenil (FLZ), Pentylenetetrazol (PTZ), (-)-Epigallocatechin Gallate (EGCG), and clarithromycin (CLR). The computational modeling of modulator-receptor interactions predicted drug action at canonical binding sites and novel orphan sites on the receptor. Our findings suggest that multiple avenues of investigation are now open to investigate large and brain-penetrant molecules for the treatment of patients with diminished CNS E/I balance.

Radial Point Interpolation-Based Error Recovery Estimates for Finite Element Solutions of Incompressible Elastic Problems

Error estimation and adaptive applications help to control the discretization errors in finite element analysis. The study implements the radial point interpolation (RPI)-based error-recovery approaches in finite element analysis. The displacement/pressure-based mixed approach is used in finite element formulation. The RPI approach considers the radial basis functions (RBF) and polynomials basis functions together to interpolate the finite element solutions, i.e., displacement over influence zones to recover the solution errors. The energy norm is used to represent global and local errors. The reliability and effectiveness of RPI-based error-recovery approaches are assessed by adaptive analysis of incompressibility elastic problems including the problem with singularity. The quadrilateral meshes are used for discretization of problem domains. For adaptive improvement of mesh, the square of error equally distributed technique is employed. The computational outcome for solution errors, i.e., error distribution and convergence rate, are obtained for RPI technique-based error-recovery approach employing different radial basis functions (multi quadratic, thin-plate splint), RBF shape parameters, different shapes of influence zones (circular, rectangular) and conventional patches. The error convergence in the original FEM solution, in FEM solution considering influence-zone-based RPI recovery with MQ RBF, conventional patch-based RPI recovery with MQ RBF and conventional patch LS-based error recovery are found as (0.97772, 2.03291, 1.97929 and 1.6740), respectively, for four-node quadrilateral discretization of problem, while for nine-node quadrilateral discretization, the error convergence is (1.99607, 3.53087, 4.26621 and 2.54955), respectively. The study concludes that the adaptive analysis, using error-recovery estimates-based RPI approach, provides results with excellent accuracy and reliability.

Design of a Wideband CPW Fed Fractal Antenna for Satellite Communication

A novel ‘T’ square wideband fractal antenna is proposed for satellite communication. The Wideband is achieved through the ‘T’ square fractal design and CPW feed. At first, a conventional square-shaped patch antenna is designed. Then the square-shaped patch is replaced by a Type-I fractal to achieve wideband. Finally, a Type-II fractal with an L-Shaped boundary is used to enhance the bandwidth to a greater extent. The gain of the proposed antenna ranges from 4 dB to 6.3 dB for the entire frequency range of 6.2 GHz to 14 GHz. The radiation efficiency of the antenna is noticed up to 84%. The fractal antenna resonates well throughout the entire frequency range with a VSWR of less than 2. The antenna having such a wide band characteristic can be found suitable for a wide range of applications like earth exploration satellites, fixed satellites, radiolocation, maritime radio navigation, and aeronautical radio navigation. A metal reflector is also introduced at the bottom of the antenna to produce a unidirectional radiation pattern. This increases the gain up to 9.8 dBi and a front-to-back ratio is noticed above 20 dB. The design is fabricated and the measurement results are found to be in good agreement with the simulation results.

An electrophysiological approach for low turnover and intracellular transport proteins: Improving amplification and accessibility.

SSM-based electrophysiology is an emerging technique extending the range of applications in electrophysiology. The method allows adsorption of any membranes, native, cell culture derived or organellar, to a lipid coated sensor (solid supported membrane, SSM). The large sensor of 3-mm diameter generates a 1000-fold or higher amplification compared to conventional patch clamp. These two features render the method ideal for electrogenic transporters and channels which are difficult to access by other electrophysiological methods due to their low current amplitude or because of their expression in intracellular membranes.

Design and Analysis of MSPA using FR-4 Epoxy Dielectric for Wireless Broadband Application

In modern communication devices, microstrip patch antennas are preferred to conventional antennas due to their size. In this review, a survey of commonly used techniques and designs for microstrip antennas is conducted. These techniques and designs were used by the authors to design an effective, low-profile, small, compatible, and affordable microstrip antenna. They were mostly used to design reconfigurable, multiband, and wideband antennas. After that, a initiator patch design with dimensions is provided on which technique will be used to analyze various antenna parameters. In recent years, research into microstrip patch antennas has made significant progress. Microstrip patch horns outperform conventional microstrip patches in a number of ways, including their low cost, ease of integration with integrated microwave circuits (MICs), low volume, small size, high performance, and low weight.

Preparation and Characterization of Patch Loaded with Clarithromycin Nanovesicles for Transdermal Drug Delivery

Clarithromycin (CLR), categorized as a Biopharmaceutical Classification System class II drug, has several gastrointestinal tract side effects and an extremely unpalatable bitter taste. The current study aimed to design transdermal patch-embedded CLR niosomes to overcome the aforementioned CLR-related challenges. Various niosomal formulations were successfully fabricated and characterized for their morphology, size, in vitro release, and antimicrobial efficacy. Subsequently, the CLR niosomes were loaded into transdermal patches using the solvent casting method. The polydispersity index of the niosomes ranged from 0.005 to 0.360, indicating the uniformity of the niosomes. The encapsulating efficiency (EE)% varied from 12 to 86%. The optimal Chol: surfactant ratio for drug release was found to be 0.5:1. In addition, the encapsulation of CLR into niosomal nanovesicles did not reduce the antibacterial activity of the CLR. The niosomal patch had a significantly higher permeability coefficient of CLR than the conventional patch. In addition to that, a shear-thinning behavior was observed in the niosomal gels before loading them into a niosomal patch. The flux (Jss) of the niosomal patch was significantly higher than the conventional patch by more than 200 times. In conclusion, niosome-based transdermal patches could be a promising method for the transdermal drug delivery of class II drugs and drugs experiencing GIT side effects.

Peripheral Microneedle Patch for First-Aid Hemostasis.

Despite the minimized puncture sizes and high efficiency, microneedle (MN) patches have not been used to inject hemostatic drugs into bleeding wounds because they easily destroy capillaries when a tissue is pierced. In this study, a shelf-stable dissolving MN patch is developed to prevent rebleeding during an emergency treatment. A minimally and site-selectively invasive hemostatic drug delivery system is established by using a peripheral MN (p-MN) patch that does not directly intrude the wound site but enables topical drug absorption in the damaged capillaries. The invasiveness of MNs is histologically examined by using a bleeding liver of a Sprague-Dawley (SD) rat as an extreme wound model in vivo. The skin penetration force is quantified to demonstrate that the administration of the p-MN patch is milder than that of the conventional MN patch. Hemostatic performance is systematically studied by analyzing bleeding weight and time and comparing them with that of conventional hemostasis methods. The superior performance of a p-MN for the heparin-pretreated SD rat model is demonstrated by intravenous injection in vivo.

Investigations on the Wideband Characteristics of a Cylindrical Conformal U-slot Loaded Microstrip Patch Antenna for X-Band Airborne Applications

A U-slot located symmetrically at the centre of the patch has been utilized to enhance the patch antenna’s operating bandwidth compared to the standard conventional patch. The operating frequency range of the circumferential patch antenna is from 8.61 to 11.43 GHz, while the axial patch covers the frequency range 8.71 to 11.33 GHz (covering X band). The antenna shows excellent gain with minimal variation in both E and H-planes across the operating frequency range. Moreover, the antenna achieves less than −10 dB sidelobe levels in both E and H-planes across all frequencies and configurations. The co and cross-polarization plots are also depicted to show the excellent polarization purity of the antenna for the planar and cylindrical conformal configurations. The antenna may be suitable for airborne applications where the conformability to the Arial host body is of prime importance.

A miniaturized rectangular microstrip patch antenna with negative permeability unit cell metamaterial for the band 2.45 GHz

This work presents a miniaturized rectangular patch Antenna with negative permeability metamaterial unit cell etched on the ground plane of a conventional patch antenna operating at 3.3 GHz. The new compact metamaterial (MTM) antenna is resonating at 2.45 GHz. It is 44,82% smaller than a conventional rectangular patch antenna resonating at 2.45 GHz and has a bandwidth of 183.3 MHz, a reflection coefficient of -45,36 dB and a gain of 1.37dB, the materials used for the conception are FR-4 dielectric as a substrate, its permittivity is 4.4 and cooper annulled as metal for radiating element and the ground plan, the simulation of the antenna was done with CST solver.

T-SLOT RECONFIGURABLE MICRO-STRIP PATCH ANTENNA WITH CAPACITIVE LOADING TECHNIQUE FOR WIMAX AND S-BAND APPLICATION

A lightweight, reconfigurable frequency T-slot S-band antenna (2.01 GHz) and WiMAX (3.5 GHz) implementations are suggested in this document. The T-slot is inserted into the center of the square micro-strip patch antenna. In the T-slot antenna, a 10 pF capacitor is used with the help of the capacitor frequency and a configurable antenna is obtained. This design has an advantage of size reduction up to 70.50&amp;#37; for the resonant frequency compared to a conventional square patch antenna. HFSS software is used for design and simulation of the proposed antenna.

Design of rectangular microstrip patch antenna with E-slot

The integration of an E-slot within the conventional microstrip patch antenna structure offers improved radiation characteristics and bandwidth. This research presents the design and analysis of a rectangular microstrip patch antenna with an E-slot. The proposed antenna is designed to operate at a specific frequency in the microwave range. The design process involves determining the dimensions of the rectangular patch, feedline, and E-slot to achieve the desired resonance frequency. The simulation and optimization are carried out using electromagnetic simulation software, considering the dielectric substrate properties and other relevant parameters. The E-slot is strategically placed within the patch structure to enhance the antenna's performance. It acts as an additional resonating element, contributing to increased bandwidth and improved radiation characteristics, such as gain and directivity. The integration of the E-slot modifies the current distribution on the patch, resulting in enhanced radiation properties. The performance of the proposed antenna is evaluated through various parameters, including return loss, radiation pattern, and bandwidth. Overall, the rectangular microstrip patch antenna with an E-slot presents a promising solution for achieving enhanced performance in terms of bandwidth and radiation characteristics. The proposed design opens up possibilities for further advancements in microstrip antenna technology, facilitating the development of an efficient and compact antenna structure for modern wireless applications.

Hexagonal-Triangular Combinatorial Structure Based Dual-Band Circularly Polarized Patch Antenna for GAGAN Receivers

A multilayer gap-coupled dual band hexagonal microstrip patch antenna is presented for GPS Aided GEO Augmented Navigation (GAGAN) receivers. GAGAN is developed by AAI (Airport Authority of India) and ISRO (Indian Space Research Organization) exclusively for aviation purposes with the GPS frequencies L5 (1176.45 MHz) and L1 (1575.42 MHz). The proposed GAGAN antenna has three trapezoidal and four equilateral triangular patch resonators configured to form a gap-coupled hexagonal patch on the top layer and seven equilateral triangular patches with slots in between to form the middle layer. Both the layers are fed by a single coax feed to achieve a dual band compact microstrip antenna of size 55 mm x 55 mm x 3.2 mm. Instead of designing the hexagonal antenna conventionally from a circular patch antenna, the sides of the equilateral triangular patch are truncated to obtain the proposed compact hexagonal antenna as the triangular antenna occupies less area when compared to circular or square patches for a fixed frequency. To bring in novelty with improved performance, the combinatorial structured configuration has been explored through step-by-step optimization. The aspects of GAGAN requirements like circular polarization with a single input, dual band operation and high gain with gain flatness are achieved with this compact structured antenna when compared to square and circular patch antennas. The combinatorial structures such as perturbation and truncation introduced in the patches are responsible for exciting two near-degenerate orthogonal modes producing circular polarization (CP). A cross slot etched in the center patch results in gain enhancement with a gain above 3.2 dBi over a bandwidth of 20 MHz in both the bands. Five shorting pins are added to achieve high impedance matching and good CP with an axial ratio (AR) below 2 dB. The simulated and measured results are found to be in good agreement with greater than 20 MHz operational bandwidth exhibiting CP with an omni-directional radiation pattern having high cross polar levels of -22 dB. The size reduction achieved in the proposed design is 56.79% when compared to the conventional hexagonal patch antenna. The measured 10 dB impedance bandwidth is 2.7% and 2.1% for L5 and L1 bands respectively with a 3 dB AR bandwidth of 2.3% for L5 and 2.0% for L1, satisfying GAGAN requirements.

Novel Metasurface based Microstrip Antenna Design for Gain Enhancement RF Harvesting

This paper presents an enhancement in radio frequency (RF) harvesting for conventional patch antenna using a metasurface layer (MSL). The key point behind such enhancement is inspired by Friis’ equation which states; increasing the antenna gain leads to an increase in the received power. To achieve this goal, a MSL consists of 5×5-unit cells of a modified Jerusalem cross are proposed. The proposed MSL provides gain enhancement of about 10 dBi while the gain of the patch antenna is about 1 dBi. The proposed MSL is fabricated, compacted to the antenna and experimentally characterized. The empirical results indict an excellent agreement with the numerical results in terms of |S11| and radiation patterns. In addition, a set of RF harvesting measurements are made for patch antenna with and without the MSL. The comparison between measurements shows a significant enhancement in the output voltage when the MSL is involved.