Simple Patch Research Articles

Realization of circular polarized multiple band multi-mode OAM antenna using a ring patch for IoT applications

A multiband and multi-mode antenna with circular polarized conical patterns is suitable for achieving desired spectral efficiency, increased capacity, and spatial diversity for IoT applications. However, simultaneous excitation of such circular polarized multiple Orbital Angular Momentum (OAM) modes through a single patch antenna is challenging due to the complexity of simultaneously fulfilling distinct requirements of each mode. In this paper, a ring patch antenna is designed to excite different OAM states at different frequencies simultaneously. First, characteristic mode analysis is used to analyze the possibility of simultaneous excitation of multiple OAM modes at corresponding frequencies through a simple ring patch antenna. Then, a dual port ring patch antenna is designed and fabricated to verify the capability of generating multiple OAM states at corresponding frequencies. Furthermore, it also presents the guidance to suppress unwanted OAM modes.

Temporally robust occupancy frequency distributions in riverine metacommunities explained by local biodiversity regulation

AbstractAimThe mechanisms determining the distribution of the number of sites species occupy, the occupancy frequency distribution (OFD), remain incompletely understood despite decades of research. To explore the dominant mechanisms responsible for the shape and temporal dynamics of empirical OFD, we develop a simple patch occupancy framework with intrinsically regulated local richness and fit the model to a highly replicated dataset describing macroinvertebrate, macrophyte and diatom occupancy.LocationEngland.Time periodUp to years between 1990 and 2020.Major taxa studiedMacroinvertebrates, macrophytes and diatoms.MethodsWe study the OFD in a highly replicated dataset of freshwater metacommunities in England across time. We consider temporal change in species richness, composition, and in the shape of the OFD. Goodness‐of‐fit of the steady state of a simple patch occupancy model—which predicts a log‐series OFD—to the empirical observations is assessed. Additionally, we test the capacity of the model to predict metacommunity‐scale processes.ResultsOur model provides a consistently good fit to empirical OFDs. It can additionally be used to predict metacommunity‐scale species turnover.Main conclusionsOur results support the view that metacommunity structure reflects a dynamic steady state controlled by local limits to coexistence.

A Simple Patch Antenna with Enhanced Isolation Without Extra Structure

A simple patch antenna with enhanced isolation and without extra structure is devised. The isolation is enhanced by 5 dB by loading two shorting pins, and the working frequency is not changed at 3.45 GHz. Radiation pattern is little changed after loading two shorting pins. There is no additional structure between the two antennas. Isolation is strengthened through the structure of the antenna itself.

Peripheral vascular trauma - basic management, diagnosis and treatment.

Peripheral vascular injuries occur in 1-3% of all traumas in civilian settings. The management of these injuries is often based on experience derived from war medicine where these injuries are more common. The goal of this article is to summarize basic guidelines for the diagnosis and treatment of vascular injuries. Western Trauma Association (WTA) and Eastern Association for the Surgery of Trauma (EAST) both have their own guidelines for vascular trauma management. Vascular injuries occur both in penetrating and blunt traumas. Complete vessel disruption occurs more frequently in penetrating traumas. In the case of blunt trauma, intimal defects are more common, resulting in dissection, false aneurysm, or intramural hematoma. The limb is mostly endangered due to ischemia, reperfusion injury and the compartment syndrome. Prompt diagnosis and treatment are paramount. Vascular trauma management is part of the ATLS protocol and life-over-limb principle. The primary goal is to stop the massive external bleeding. Clinical examination and CT angiography are the most helpful for the diagnosis. Surgical revision is indicated when hard signs are present. This can be a damage control surgery with the primary goal to stop the bleeding as quickly as possible. A shunt can be used for temporary reperfusion of the limb. Definitive treatment can take the form of a simple suture, patches or graft interposition; both prosthetic and autologous grafts are used. Sufficient debridement and fasciotomy are important steps in the therapy. In some cases, endovascular treatment can be used. Over the last century, the treatment strategy changed dramatically. Data from recent military conflicts show a decrease in amputation rates, and limb salvage has become a standard.

Broadband inhomogeneous lens with conical radiation pattern

This manuscript presents a lens antenna with simultaneous broadside and conical beams. The lens is designed for the Ku band using the ray inserting method. The proposed conical radiation pattern is broadband due to good matching with the source and surroundings. The simulation is conducted using the CST microwave studio solver. Instead of complex antenna shapes used in other works, a simple circular patch ring and RF connector are used as the lens feed to generate broadside and omnidirectional conical patterns, respectively. To validate the performance of the designed lens and its two-port feed antenna, the lens structure is realized and fabricated using the 3D printing method. Polyethylene terephthalate glycol (PETG) plastic material is utilized for constructing the lens in this work. The electromagnetic characteristics of PETG in the Ku band are accurately measured. The results of simulations and experiments demonstrate the good performance of the designed lens over a wide frequency bandwidth. The advantage of this designed structure over other works is its high gain and broad bandwidth.

Multi-Task Distributed Learning using Vision Transformer with Random Patch Permutation.

The widespread application of artificial intelligence in health research is currently hampered by limitations in data availability. Distributed learning methods such as federated learning (FL) and split learning (SL) are introduced to solve this problem as well as data management and ownership issues with their different strengths and weaknesses. The recent proposal of federated split task-agnostic (FESTA) learning tries to reconcile the distinct merits of FL and SL by enabling the multi-task collaboration between participants through Vision Transformer (ViT) architecture, but they suffer from higher communication overhead. To address this, here we present a multi-task distributed learning using ViT with random patch permutation, dubbed p-FESTA. Instead of using a CNN-based head as in FESTA, p-FESTA adopts a simple patch embedder with random permutation, improving the multi-task learning performance without sacrificing privacy. Experimental results confirm that the proposed method significantly enhances the benefit of multi-task collaboration, communication efficiency, and privacy preservation, shedding light on practical multi-task distributed learning in the field of medical imaging.

Design and Development of Ultrabroadband, High-Gain, and High-Isolation THz MIMO Antenna with a Complementary Split-Ring Resonator Metamaterial.

The need for high-speed communication has created a way to design THz antennas that operate at high frequencies, speeds, and data rates. In this manuscript, a THz MIMO antenna is designed using a metamaterial. The two-port antenna design proposed uses a complementary split-ring resonator patch. The design results are also compared with a simple patch antenna to show the improvement. The design shows a better isolation of 50 dB. A broadband width of 8.3 THz is achieved using this complementary split-ring resonator design. The percentage bandwidth is 90%, showing an ultrabroadband response. The highest gain of 10.34 dB is achieved with this design. Structural parametric optimization is applied to the complementary split-ring resonator MIMO antenna design. The designed antenna is also optimized by applying parametric optimization to different geometrical parameters. The optimized design has a 20 µm ground plane, 14 µm outer ring width, 6 µm inner ring width, and 1.6 µm substrate thickness. The proposed antenna with its broadband width, high gain, and high isolation could be applied in high-speed communication devices.

Investigation of a novel heat dissipation concept with controllable thermal and EM performance for reliable electronics and communication systems

This paper presents a novel efficient heat dissipation concept in electronics with switch controllable thermal and electromagnetic (EM) performance. Besides the traditional implementation of heatsinks on the back of the antenna in communication systems, a passive technique by introducing a reconfigurable heatsink that reuses the air space above the antenna for additional heat dissipation channels is proposed. The non-contact heatsink is lifted with a tiny air gap from the antenna and partially connected with the antenna through physical switches/poles that balance the EM performance and heat dissipation efficiency, which eliminates the negative impact of the heatsink on the antenna EM performance. EM effects of heatsink on the antenna in terms of locations of contacts, states of switches, and various dimensions are thoroughly investigated. To demonstrate the design efficacy for optimized thermal efficiency and EM performance, a properly designed heatsink is implemented on the top of a simple patch antenna. The measured results show that good heat dissipation is achieved without deteriorating the EM performance of the antenna, in respect to return loss, gain, and radiation patterns. When the switches are OFF and ON, the reflection coefficient of the antenna is measured as −20.82 dB and −17.56 dB, respectively. In addition, with a 20 mW heat source at the input port of the antenna to mimic the heat generation from the electronics, the temperature of the antenna surface is reduced with the front-integrated heatsink by 7.4 °C and 13.4 °C when the connection switches are turned OFF and ON. The implementation of the front-integrated heatsink on the antenna fully demonstrates the proposed heat dissipation concept which provides an effective way to solve the tradeoff between thermal inefficiency and EM performance.

Highly Efficient and Multiband Metamaterial Microstrip-Based Radiating Structure Design Showing High Gain Performance for Wireless Communication Devices

High-speed wireless communication devices need antennas to operate at multiple frequencies with high gain. The need for such antennas is increasing day by day. The proposed metamaterial superstrate antenna gives a high gain and multiband performance, which is required in high-speed wireless communication devices. The designed antenna is also applicable for C- and X-band communication devices. The structure consists of a simple patch and multiple split-ring resonator metamaterials on the superstrate region. The performance optimization is achieved by adjusting the feed position, varying the height of the superstrate layer and changing the thickness of metamaterial rings. The proposed design is analyzed for 4 GHz to 12 GHz. The performance analysis regarding the reflection coefficient, directivity, gain and electric field is observed. FR4 is used as a dielectric material that makes the design low-cost. The proposed design represents a minimum reflection coefficient response of −49 dB, a bandwidth of 490 MHz, a maximum electric field of 1.29 × 104 v/m, good directivity and a broader radiation pattern. The comparison between the simulated and the measured results is incorporated in the manuscript. A comparison of the presented design with other articles is included to check the novelty of the design. The proposed method helps to target applications such as WiFi, Earth observation and microwave links.

A Compact Circular Rectenna for RF-Energy Harvesting at ISM Band

With low-power gadgets proliferating, the development of a small, effective rectenna is crucial for wirelessly energizing devices. A simple circular patch with a partial ground plane for RF-energy harvesting at ISM (2.45 GHz) band is proposed in this work. The simulated antenna resonates at 2.45 GHz with an input impedance of 50 Ω and a gain of 2.38 dBi. An L-section matching a circuit with a voltage doubler is proposed to provide excellent RF-to-DC transformation efficiency at low power input. The proposed rectenna is fabricated and the results show that the return loss and realized gain have good characteristics at the ISM band with 52% of RF-to-DC transformation efficiency, with an input of 0 dBm power. The projected rectenna is apt for power-up low sensor nodes in wireless sensor applications.

A simple design and fabrication of polarization reconfigurable antenna for industrial scientific and medical-band applications

<span lang="EN-US">This paper proposes a simple microstrip patch antenna (MPA) that can reconfigure its polarization states from linear to circular polarization in real-time by means of a PIN diode. An antenna is fed by a 50 Ω coaxial cable through the substrate of Teflon with relative permittivity of 2.15. The proposed antenna possesses a simple patch with a one-sided corner truncated to achieve polarization reconfigurability. A PIN diode is loaded to connect the main patch with a truncated corner and further maintain dual polarization states such as linear polarization (LP) and circular polarization (CP). Advanced design system (ADS) was used as a simulator to simulate the antenna, and a good understanding was obtained between simulated and measured results. Measured results showed a good agreement with simulated results at all working frequencies of interest. It shows minimum reflection coefficient gain with -10 dB scattering bandwidth 100 MHz for LP states and 170 MHz for CP states. It also shows an axial ratio of 1.56 dB for CP, and the cross-polarization level is also in a satisfying range.</span>

Design and Experimental Evaluation of a Printed Monopole Antenna for GPR Applications

In this paper, a printed monopole antenna is designed and experimentally evaluated for Ground Penetrating Radar (GPR) applications. The antenna resonates at two narrow frequency bands centered at 0.5 GHz and 2 GHz. Four stages are used to achieve the final model, which is based on a rectangular patch, a simple microstrip feed line, and a reduced ground plane. The proposed antenna consists of a simple patch with notches and a quarter-wavelength feed line. The introduced notches help to reduce the conductor losses and decrease the weight of the design. The antenna prototype is fabricated on a low-cost FR-4 epoxy substrate with dimensions of 17.55 cm3, using the LPKF S103 laser printer, and then measured with the R&S®ZNB Vector Network Analyzer. The experimental results demonstrate that the operating bands range between 0.48–0.52 GHz (8%) and 1.94–2.04 GHz (5.02%). The antenna exhibits good radiation patterns with a reasonable gain of 1.5/2.6 dBi and a high radiation efficiency of 97/78% at the two resonating frequencies 0.5/2 GHz, respectively. To validate the usefulness of the designed antenna for GPR applications, a penetrability test is conducted through a concrete separator wall. The electric field probe HZ551 is used to receive the electromagnetic waves behind the obstacle, and the power received by the probe is measured with the GSP-730 spectrum analyzer. The obtained results confirm that the proposed model performs well in the UHF band at 0.5 GHz and 2 GHz, with a high level of penetrability.

METHOD OF DESIGNING ANTENNAS BY SYNTHESIS OF A BAND FILTER

A novel antenna design technique is proposed, which offers bandwidth enhancement up to the limits defined by element radiation efficiency. The employed technique is referred as frequency pulling (FP) as it mimics the insertion loss design methodology of bandpass filters. This is essentially a wideband matching approach pushing the antenna efficiency to the limits set up by radiation efficiency. There are three options towards this trend: (1) first to enhance a single element bandwidth (compact element) exploiting its possibly multiple symmetrical feeding points as distinct resonator ports, (2) frequency pulled array as to design a small antenna array (less than about 10 elements) where eachelement acts as a resonator and (3) second order frequency-pulled array as to build a small array using compact elements of category (1). Similar to the band-pass filter design, all antennas or distinct-port circuits resonate at the same resonant frequency when isolated, cascading two or more of them; FP yields to multiple-overlapping successive resonances in their overall response. Although the proposed technique is general within this first effort, it is applied to simple patch antenna elements exhibiting multiple symmetrical feeding points, namely two-for rectangular, four-for square and five-for pentagonal. The third option is applied to an array of three compact 4-feeding point square elements offering triple bandwidth with respect to the already wideband single element. However, this is achieved at the expense of a significant beam squint. Thus, in general, these wideband compact elements should be used within a classical array design. Further bandwidth enhancement using FP to antenna elements with inherent multiple resonances as patches with slots or truncated edges constitutes our next task. Their inherent wider bandwidth in radiation efficiency is expected to allow multiply higher bandwidths when exploited with our FP technique.

Design and Fabrication of the Split Ring Resonator Shaped Two-Element MIMO Antenna with Multiple-Band Operation for WiMAX/5G/Zigbee/Wi-Fi Applications.

In this manuscript, we proposed the split ring resonator loaded multiple-input multiple-output (MIMO) antenna design for the frequency range of 1 and 25 GHz. The proposed antenna is numerically investigated and fabricated to analyze the different antenna parameters. We provided statistics on a wide range of antenna parameters for five different designs, including a simple circular patch antenna, a single-split-ring antenna, and a double-split-ring antenna. Reflectance, gain, directivity, efficiency, peak gain, and electric field distribution are all analyzed for all proposed antennas. The maximum achievable bandwidth is 5.28 GHz, and the double-split-ring resonator structure achieves this with a return loss of -20.84 dB. The radiation patterns of all the antenna with different port excitation conditions are presented to identify the behavior of the antenna radiation. We found the effect of the split-ring resonators to form radiation beams in different directions. We found the maximum and minimum half-power beam widths of 75° and 2°, respectively, among the different antenna designs. It was found that the split-ring resonator geometries in patch antenna convert wide-beam antenna radiation patterns to several narrow-beam radiation patterns. We found that each antenna's bandwidth, gain, and return loss performance significantly differs from the others. Overall, the proposed results of the antenna may apply to a wide range of communication applications, including those for Wi-Fi, WiMAX, and 5G.

Application of Dielectric-Artificial Magnetic Conductor Composite Substrate to Design Miniaturized P-Band Microstrip Antenna for Wireless Underground Sensor Network

In the modern era of wireless Internet of Things designing a planar antenna at relatively low frequency (P-band) with positive gain and high efficiency is exacting task. In this letter, a planar P-band microstrip antenna (a simple rectangular patch of size 0.16λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> ×0.20λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> ×0.01λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> , smaller than classical quarter-wave patch) for wireless underground sensor network (WUSN) is proposed. The proposed structure yields high gain with the judicious use of four shorting vias, which are collocated along the side edges of the patch with a composite substrate (dielectric-artificial magnetic conductor). The results shows that the designed antenna resonates at 413 MHz with gain and efficiency of 3.1 dBi and 75%, respectively, with a 10 dB impedance bandwidth of 2% (408–416 MHz)

MIPNet

We present MIPNet, a novel approach for SVBRDF mipmapping which preserves material appearance under varying view distances and lighting conditions. As in classical mipmapping, our method explicitly encodes the multiscale appearance of materials in a SVBRDF mipmap pyramid. To do so, we use a tensor-based representation, coping with gradient-based optimization, for encoding anisotropy which is compatible with existing real-time rendering engines. Instead of relying on a simple texture patch average for each channel independently, we propose a cascaded architecture of multilayer perceptrons to approximate the material appearance using only the fixed material channels. Our neural model learns simple mipmapping filters using a differentiable rendering pipeline based on a rendering loss and is able to transfer signal from normal to anisotropic roughness. As a result, we obtain a drop-in replacement for standard material mipmapping, offering a significant improvement in appearance preservation while still boiling down to a single per-pixel mipmap texture fetch. We report extensive experiments on two distinct BRDF models.

SEMICIRCULAR SLOT BASED UWB MICROSTRIP PATCH ANTENNA FOR VARIABLE BAND NOTCHED APPLICATIONS

The patch antenna with Ultra-Wide Band (UWB) characteristics is a promising candidate for wireless communication. It is a major research problem to mitigate electromagnetic interference (EMI) with narrowband technologies such as 5G lower band, Wi-MAX, WLAN and satellite band, which are all in the UWB region. This study describes a UWB antenna with variable band rejection that can be used to avoid interference with Wi-MAX and 5G lower band applications. The UWB characteristics of a simple rectangle patch antenna with a faulty ground structure has been designed for operational bandwidth (2.7–13) GHz. A novel method semicircular slot (SCS) at the radiation patch creates a band notched from (3.25–3.80) GHz and (3.4–4) GHz. Variable band rejection between (2.95–4.40) GHz can be achieved by adjusting the “Wa” values. When measured over the band rejection frequency, the return loss (S11) and VSWR values are very close to 0 dB and larger than 2. The simulated and measured results such as return loss, VSWR, 2-D polar pattern and gain have almost similar agreement. The design of the suggested antenna is simple, compact and efficient for Wi-MAX application, this is an ideal UWB antenna with the band notch characteristics.

Practical Approach to Minor Burns

Most mild burns may be treated well in an outpatient environment and recover with little intervention. An precise categorization of burns is essential to ensuring effective treatment. Any non-superficial burn should be treated with a topical antibiotic to avoid infection. Although partial and full-thickness burns frequently require dressings, superficial burns typically do not. Especially in an emergency situation, a simple gauze patch offers enough burn protection. Increasing burn depth and contracture, monitoring for symptoms of infection, and providing appropriate analgesia are all parts of follow-up treatment. All suspected partial or full-thickness burn infections require prompt treatment, which may include hospitalization and parenteral antibiotics. Burn infections can increase the depth and breadth of a burn, turning a superficial partial-thickness burn into a deep partial-thickness or full-thickness burn in addition to producing sepsis.

Water Pollution Level Detection using Patch Antenna Measurements at Microwave Frequencies

The detection of pollutants and their concentrations in water is very important because they can be a public hazard. The level of pollution in water can be determined using various microwave and chemical measurement/analysis techniques. This work aims at demonstrating a new technique of determining the pollution levels in water by detecting the change in resonant frequency of simple patch antenna while immersed in water that is mixed with chemicals of various concentrations. Water mixed with chemi-cals has a dielectric constant different from that of pure water. This change in the dielectric constant of water will result in shift of resonant frequency of antenna (when the antenna is immersed in water). In addition, a theoretical study has been performed to determine the dielectric constant of water with different concentrations of sodium chloride. The calculated dielectric constant is used to set the parameters in a simulation software that also simulates the shift in resonant frequency when an antenna is immersed in water. Both the simulated and the measured shift in resonant frequency is found to be comparable. The effectiveness of this method is demonstrated by performing antenna measurements immersed in water collected from various sources in Kerala, India.

Circular slotted patch with defected grounded monopole patch antenna for microwave-based head imaging applications

Medical microwave imaging (MWI) research has gained more attention in recent decades, particularly with regard to the early detection of brain tumors. It offers numerous benefits over existing imaging technologies, including magnetic resonance imaging (MRI) and computed tomography (CT) scans. Antennas represent a key element of MWI systems, so optimizing their performance is critical. A new, simple patch antenna for MWI is presented in this article. The radiating patch has a circular slot and a tiny triangular cut at the top right corner, and it is designed and manufactured with a low-cost FR4-epoxy substrate with a loss tangent of 0.02 and a dielectric constant of 4.4. The overall dimensions are 0.28λ × 0.22λ × 0.005λ (where λ is the wavelength of a lower frequency of 1.22 GHz). A total impedance bandwidth (<-10 dB) of 2.23 GHz (1.22–3.45 GHz) is achieved with a very decent gain of above 5 dBi (measured) and above 85 % efficiency over the functional range. Time-domain assessment of the antenna confirms minimum signal distortion and shows a better response in terms of group delay (GD) and fidelity factor (FF, 92 %). Measurements confirm the results from simulations (CST and HFSS) with a reasonable degree of agreement. Finally, the 3D-electromagnetic CST simulator was utilized to analyze the behavior of a nine-antenna array placed around a 3D-realistic Hugo-head model; it yielded satisfactory results and proved the practical utility of the proposed antenna in the intended MWI application.