Triangle Patches Research Articles

Metasurface-inspired circularly polarized patch antenna using DGS for sub 6-GHz applications

A novel circularly polarized metasurface inspired regular triangle patch antenna (RTPA) with enhanced gain and bandwidth is proposed in this paper. The antenna is composed of a triangular patch-driven element sandwiched between a 3×3 sub-wavelength square patch metasurface array and the ground plane. Initially, the RTPA is designed, and the ground plane is etched with fractal slots to produce degenerate modes for circular polarization. A metasurface array is used as a superstrate to improve gain and bandwidth in terms of impedance and axial ratio (AR). Another advantage of using a metasurface is the reduction of cross-polar radiation, particularly when employing a triangular-shaped patch antenna. The asymmetry of this structure leads to cross-polar components contributed by dominant modes rather than higher-order modes, and the use of a metasurface markedly diminishes these components. The proposed antenna's experimental results show a 10 dB return loss (|S11|) with a metasurface demonstrates a measured impedance bandwidth and axial ratio bandwidth of 760 and 350 MHz, respectively. The antenna exhibits right-hand circular polarization with a measured gain of 5.87 dBic at the operating frequency.

Miniaturized Wideband Circularly Polarized Triangular Patch Antennas based on Characteristic Mode Analysis

A miniaturized, wideband circularly polarized (CP) antenna based on coupled triangular patches is presented. Initially, two identical triangular patches with shorting pins are placed close to each other in a perpendicular orientation. Hence, a pair of orthogonal modes can be produced based on the coupled resonators. Under the characteristic mode analysis (CMA), it can be found that the 90∘ phase difference is achieved by modulating gap distance and shorting pins numbers. Both the shape of triangle patches and shorting pins contribute to the miniaturization. To further improve the AR bandwidth, a third patch is added to form a new mode. Thanks to the triple modes produced by the three patch elements, two AR minima are constructed to broaden the AR bandwidth. With this compact arrangement and shorting pins, a miniaturized wideband CP patch antenna with a 5.2% AR bandwidth is successfully implemented. The overall size of the antenna is merely 0.34λ0×0.33λ0×0.046λ0.

Cloaking of Equilateral Triangle Patch Antennas and Antenna Arrays with Planar Coated Metasurfaces

We have proposed an effective metasurface design to accomplish the cloaking of equilateral patch antennas and their array configuration. As such, we have exploited the concept of electromagnetic invisibility, employing the mantle cloaking technique with the intention to eliminate the destructive interference ensuing between two distinct triangular patches situated in a very congested arrangement (sub-wavelength separation is maintained between the patch elements). Based on the numerous simulation results, we demonstrate that the implementation of the planar coated metasurface cloaks onto the patch antenna surfaces compels them to become invisible to each other, at the intended frequencies. In effect, an individual antenna element does not sense the presence of the other, in spite of being in a rather close vicinity. We also exhibit that the cloaks successfully reinstate the radiation attributes of each antenna in such a way that it emulates its respective performance in an isolated environment. Moreover, we have extended the cloak design to an interleaved one-dimensional array of the two patch antennas, and it is shown that the coated metasurfaces assure the efficient performance of each array in terms of their matching as well as radiation characteristics, which in turn, enables them to radiate independently for various beam-scanning angles.

Integral Hydro-Bulge Forming Method of Spherical Pressure Vessels Using a Triangle Patch Polyhedron

AbstractThis paper proposes an integral hydrobulge forming (IHBF) method using a triangular patch polyhedron as the closed preform shell. When triangular flat parts are welded along the edges in sequence, triangular patch polyhedra are naturally formed. From the radius of the spherical pressure vessel, a design formula was derived to calculate the side lengths of the triangular flat plate parts. The water pressure, water volume, average strain of molding, and amount of springback after molding, which are necessary for implementing the IHBF for practical use, were also formulated. To verify the forming performance of the spherical pressure vessel using IHBF method, the finite element method was carried out, and a stainless-steel spherical pressure vessel with a thickness of 1.0 mm and a diameter of approximately 500 mm was fabricated using the proposed IHBF method. As a result, the measured shape error expressed as roundness to diameter ratio was 0.52%, and the calculated average plastic strain was 0.02, which was approximately 1/19 times of the forming limit strain of the material. The amount of springback after forming by calculation was approximately 0.7 mm, indicating that the amount of water required for IHBF was 5.90% of the volume of the spherical pressure vessel, while the required water pressure was no bigger than 2.3 MPa. The process directly utilizes triangular flat plate parts, eliminating the need for molds to process closed preform shells resulting in a low average plastic strain during forming, thereby improving the quality of the formed spherical pressure vessels.

Compact Slit-Loaded ACS-Fed Monopole Antenna for Bluetooth and UWB Systems With WLAN Band-Stop Capability

A compact asymmetric coplanar strip (ACS)-fed monopole antenna is presented, which operates within the Bluetooth and UWB frequency bands with the capability to simultaneously reject the lower WLAN interfering band. The antenna consists of an inverted right triangle patch monopole loaded by open-ended L-shaped slits not only to produce the additional 2.4 GHz passband to the UWB design but also to achieve stopband characteristics around 5.2 GHz. The conceptual equivalent circuit model as well as characteristic mode analyses are carried out in the design evolution process. The proposed antenna has an overall size of only 20 mm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times10$ </tex-math></inline-formula> mm, having the smallest area among the so far developed designs, which can be easily integrated within any wireless gadgets. A prototype is fabricated and measured to validate the design, demonstrating the predicted behavior fairly achieved by full-wave analysis. The antenna −10 dB operating bandwidth ranges from 2.38 to 2.42 GHz and from 3.35 to 11 GHz while rejecting from 4.69 to 5.2 GHz. Unlike the unwanted stopband, where the radiation characteristics are adequately deteriorated, the proposed antenna fairly provides stable omni-directional radiation patterns in the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${H}$ </tex-math></inline-formula> -plane, and has an average efficiency (gain) of 87.3% (2.6 dBi) in the desired passband. As far as the antenna transient behavior is concerned, an adequate measured (simulated) system fidelity factor of 0.7 (0.68) is achieved for the transmission of impulse-type UWB signals in the face-to-face configuration.

Wideband Ferrite-Loaded Bow-Tie Antenna of Extremely Low-Profile

A large ground plane can severely degrade an antenna’s performance if its polarization is parallel to the ground and its profile is only a very small fraction of the operating wavelength. In this article, a wideband and very low-profile bow-tie dipole antenna is proposed to operate in the VHF/UHF band, which can be placed above a large ground plane. A step-by-step design with three main strategies: adding parasitic shorted walls, inserting parasitic triangle patches, and employing ferrite material, is introduced to make the antenna radiate in a wide band and maintain a very low profile. Another two methods using folded strips and modified interfingered structure are adopted to achieve the challenging goal of its realized gain greater than 2.0 dBi over a bandwidth of 218–650 MHz. The antenna’s profile is only <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.036~\lambda _{0}$ </tex-math></inline-formula> and its area is only <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.22\times 0.44\,\,\lambda _{0}$ </tex-math></inline-formula> , where <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda _{0}$ </tex-math></inline-formula> is the free-space wavelength at the lowest frequency of 218 MHz. Experimental verification is carried out, and the measured results are in good agreement with the simulated ones.

Research on Collision Detection Algorithm for Human-SRL Collaborative Motion Planning

The existing collision detection algorithms are commonly based on triangle patch models, which leads to complex detection logic. Aiming at this problem, this paper proposes a new collision detection algorithm. It has simple detection logic and fast detection speed, and it is mainly used for human-SRL cooperative motion planning. The algorithm is based on a human-SRL skeleton model and a multi-sphere envelope method and includes four sub-algorithms, namely, a multi-sphere envelope sub-algorithm, an SRL collision detection sub-algorithm, a collision detection sub-algorithm between SRL and human, and a collision detection sub-algorithm between SRL and environment objects. This paper first introduces the pseudo-code of the collision detection algorithm. Secondly, the implementation principles of its four sub-algorithms are expounded. Finally, the correctness of the collision detection algorithm is verified by simulation.

Wideband Three-Way Filtering Power Divider on One Single Multimode Patch Resonator

This article proposes a novel wideband three-way filtering power divider (FPD) based on one single multimode patch resonator (MPR). Firstly, by researching the unique trilateral symmetry properties of equilateral triangle patch resonator (ETPR) modes, the TM11 and TM30 resonant modes have been exploited to establish the three-way power division. Then metallic vias and slots perturbations are introduced to flexibly control the resonant mode frequencies to realize the assumed two-order filtering response. Ultimately, a resistors-grounded isolation network is developed for decent in-band isolations. For validation, a prototype with center frequency at 5.1 GHz and with 3-dB fractional bandwidth (FBW) of 21% is designed, simulated, and fabricated. The measured results show good agreements with simulated ones along with wide passband, good frequency selectivity, and in-band isolation. Finally, an extended discussion is also provided to further demonstrate the flexibility and extendibility of the proposed design method.

Coding‐Feeding Metasurface for Diffusion and Dual‐Band Emission (Adv. Theory Simul. 8/2022)

Coding-Feeding Metasurface for Diffusion and Dual-Band Emission In article 2200006, Si Jia Li and co-workers develop a new type of coding-feeding metasurface by combining an emission patch and two arc triangle patches for polarization conversion in a shared aperture, digitally realizing the scattering diffusion and dual-band radiation simultaneously. This metasurface with a lightweight, compact and low profile has potential applications in stealth aircraft systems and wireless communications.

Coding‐Feeding Metasurface for Diffusion and Dual‐Band Emission

AbstractAs 2D metamaterials, metasurfaces are well known due to the distinctive manipulation of the amplitude, phase, polarization, and propagation for electromagnetic (EM) waves. However, the existing metasurfaces are mainly designed to control the incident waves. Herein, a coding‐feeding metasurface (CFMS) with two functions of dual‐band emission and diffusion for incidences simultaneously is proposed. The zigzag emission patch and two arc‐split triangle patches for polarization conversion are nested together on a shared aperture of a unit cell for CFMS. The genetic optimization algorithm is introduced for diffusion. A prototype is fabricated and measured to validate the proposed CFMS with dual‐function. The experimental results agree well with the simulated data, which verify the diffusion and emission for CFMS. The CFMS with the lightweight, compact, and low profile has the potential applications in imaging, detection, and wireless communication systems for stealth aircraft.

"Roof" technique-a modified aortotomy closure in Y-incision aortic root enlargement upsizing 3-4 valve sizes.

"Roof" technique-a modified aortotomy closure in Y-incision aortic root enlargement upsizing 3-4 valve sizes.

A Compact Multimode OAM Antenna Using Sequentially Rotated Configuration

For multiplex beams of orbital angular momentum, we propose a two-looped concentric uniform circular array consisting of sequentially rotated circular polarization (CP) triangle patches. Generally speaking, the rotation of the CP antenna makes feeding networks free of narrowband phase shifters. Further investigations also reveal that CP performances of elements and the rotation parameters (including directions and centers) are critical factors. Moreover, adopting the triangle patches makes the array compact and wideband. A demonstration with 12 elements is designed and fabricated, whose radius is only 0.76 λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> . Simulations and measurements suggest that it could emit circularly polarized vortex waves of modes −1 and −2 at the X-band simultaneously, and its bandwidth is about 8.7%.

Two- and Three-Way Filtering Power Dividers With Harmonic Suppression Using Triangle Patch Resonator

This paper presents a new approach to design filtering power dividers (FPD) with regular triangle patch resonator (RTPR). According to the electric-field (E-field) distributions of the resonator modes, the TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">10</sub> and TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> modes have been selected to realize two- and three-way power dividers respectively, showcasing the flexible characteristic of the RTPR. Afterwards, an in-phase multiway excitation scheme for the RTPR is developed to well excite the designated modes and suppress multiple spurious modes, simultaneously. Subsequently, to further reject the harmonics so as to extend the upper stopband greatly, shorting posts are deployed at the locations with null electric field distribution for the specified operation mode. Ultimately, to validate the design concept, a two-way and a three-way second-order FPD employed at TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">10</sub> ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$f_{10}= 1.27$ </tex-math></inline-formula> GHz) with fractional bandwidth (FBW) of 7% and at TM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$f_{11}= 2.2$ </tex-math></inline-formula> GHz) with FBW of 4.5% are designed and measured. The measured results of the two fabricated circuits well agree with the simulated ones. Results indicate that both of the two FPDs exhibit properties of good port-to-port isolation, high selectivity with transmission zeros near both sides of the passband, as well as wide stopband extended to 3.35 and 2.9 times of fundamental operation frequencies, respectively.

A Terahertz Metamaterial Absorber-Based Temperature Sensor Having Nine Resonance Peaks

Design and investigation of a polarization-insensitive nine-band tunable metamaterial absorber at THz frequencies with equal to or more than 90% absorption ratio in all of the bands are reported. The tunable metamaterial absorber consists of four isosceles triangle patches with four U-shaped cut paths on top of an indium antimonide substrate, which has a fully metallic ground plane at the backside. Numerical analyses show that the metamaterial absorber has wide-angle characteristics under transverse-electric and transverse-magnetic modes. The permittivity of indium antimonide is highly dependent on temperature variations due to its temperature-dependent intrinsic carrier density, leading to shift of nine absorption peak frequencies upon change of environment temperature. Broadband switching of nine absorption peak frequencies with maximum 71.5% shift ratio between 190 K and 230 K is obtained. Temperature sensing performance of the metamaterial absorber is further evaluated and the sensitivities are found to be 11.5 GHz/K, 9.2 GHz/K, 8.3 GHz/K, 7.6 GHz/K, 7.0 GHz/K, 6.2 GHz/K, 5.3 GHz/K, 4.5 GHz/K and 4.2 GHz/K, from the first to ninth absorption band, respectively. Therefore, the proposed nine-band metamaterial absorber sensor has great potential in sensitive and accurate temperature measurement, absorption tuning in optoelectronic applications and as frequency selective thermal emitters.

Design of super compact ultrathin perfect wide‐angle polarization independent metamaterial absorber for C, X, and Ku band applications

AbstractThis article focuses on the design of super compact, polarization insensitive with wide angular stability, ultrathin triple‐band metamaterial absorber. The unit cell comprising patches achieves almost perfect absorption (close to 100%) at C, X, and Ku band thereby justifying the term perfect metamaterial absorber. The structure provides 99.96%, 99.98%, and 99.62% absorptivity at the 4.75 GHz (C‐band), 9.47 GHz (X‐band), and 14.40 GHz (Ku‐band), respectively. The dimension of the structure is super compact of the order of 7.2 × 7.2 × 0.8 mm3 along with the ultrathin profile. The unit cell thickness is 0.012 λlowest (where λlowest is at a lowest cut‐off frequency). The proposed absorber comprises an outermost ring, split ring, innermost ring and square line with triangle patches at the boundary. The combinational effect of rings and internal patch provides perfect absorption at designated frequencies. Further, equivalent circuit is explained for the proposed design. The absorptivity remains insensitive towards transverse electric and transverse magnetic polarized wave and exhibits matched absorption. Moreover, the stability of the proposed design is validated with the different incident (for TE and TM modes) and polarization angles. The results are found close to perfect absorption. Finally, the simulated results are validated with measured results and found in close agreement.

A wideband microstrip triangle patch antenna with double dumbbell shaped Defective Ground Structure for 5G application

In the 5G cellular communication system requires an antenna that has a wide bandwidth and works at millimeter-wave frequencies. In this study, the addition of defective ground structure (DGS) to a microstrip triangle antenna was developed to improve bandwidth performance. Development is carried out through the addition of a double dumbbell-shaped at the DGS antenna structure that works at 28 GHz for 5G applications. The sample design is 4T4R microstrip antenna using Rogers RT5880 substrate material with a dielectric constant (ε_r) of 2.2, h = 0.787 mm. The sample antenna design has dimension 30.11 × 19.89 mm. This study uses a research and development approach through the calculation of DGS structure and design of multiple dumbbell-shaped on the ground layer. The simulation and measurement results show a significant increase in bandwidth performance compared to without using DGS. This study also shows the improvement in bandwidth performance and the gain of microstrip antenna with the addition of double dumbbell-shaped compared to the addition of single dumbbell-shaped in previous studies.

A Low-Profile Wideband Antenna With Monopolelike Radiation Characteristics for 4G/5G Indoor Micro Base Station Application

A wideband, low-profile, vertically polarized antenna with monopolelike radiation characteristics is proposed for 4G/5G indoor base station applications. The design of this antenna is based on the traditional monocone antenna with internal matching and reactive load. The structure of monocone is realized by crossed substrate, which reduces the antenna weight and improves the design flexibility simultaneously. Then, reactive loading of capacitively coupled triangle patches and shorting pins are used to reduce the height of antenna profile to 0.08 λ min, where λ min is the free-space wavelength at the lowest operation frequency. An interdigital capacitor is etched near the antenna's input to adjust the impedance matching. The proposed antenna demonstrates consistent monopolelike, omnidirectional radiation patterns within the operating band. A measured impedance bandwidth for voltage standing-wave ratio (VSWR) < 2.2 of about 81% ranging from 1.66 to 3.95 GHz is achieved, which covers 1.7–2.7 GHz 4G Long-Term Evolution band and 3.3–3.8 GHz 5G N78 band simultaneously. The proposed antenna is tailored for the ceiling micro base station in indoor distributed system.

Simple primitive recognition via hierarchical face clustering

We present a simple yet efficient algorithm for recognizing simple quadric primitives (plane, sphere, cylinder, cone) from triangular meshes. Our approach is an improved version of a previous hierarchical clustering algorithm, which performs pairwise clustering of triangle patches from bottom to top. The key contributions of our approach include a strategy for priority and fidelity consideration of the detected primitives, and a scheme for boundary smoothness between adjacent clusters. Experimental results demonstrate that the proposed method produces qualitatively and quantitatively better results than representative state-of-the-art methods on a wide range of test data.

Transient Electromagnetic Analysis of Multilayer Graphene with Dielectric Substrate Using Marching-on-in-Degree Method

The marching-on-in-degree (MOD) method is applied in this paper to analyze the transient electromagnetic scattering of multilayer graphene and a dielectric substrate. The time domain resistive boundary condition (TD-RBC) integral equation and time domain Poggio–Miller–Chang–Harrington–Wu (PMCHW) integral equation of electric and magnetic currents are employed to model graphene and the dielectric substrate, respectively. These two sets of equations are coupled and solved with the MOD method. The dispersion of multilayer graphene’s surface conductivity/resistivity in the frequency domain is taken into account in the analytical convolution of temporal surface conductivity/resistivity and magnetic/electric current densities. The Rao-Wilton-Glisson (RWG) basis function over triangle patches and weighted Laguerre polynomial (WLP) are used as the spatial and temporal basis/testing functions, respectively. The orthogonal WLPs are defined from zero to +∞ and are convergent to zero with time passing. These advantages ensure late time stability of the transient solution. A stable electric/magnetic current is achieved. A radar cross section and extinction cross section in the frequency domain are also obtained and compared with commercial software results to verify the proposed method.

Miniaturized Spoof Surface Plasmon Polaritons Low-Pass Filter With a Novel Transition Structure

In this letter, a miniaturized spoof surface plasmon polaritons (SSPPs) low-pass filter with a novel transition structure is proposed. The novel transition structure is designed by two rectangular strips with an inclination of 17° and right-angled triangle patches. In this letter, we analyzed the normal and azimuthal components of the electric field perpendicular to the plane of the filter at different locations, verifying the effectiveness of the transitional structure. Besides, efficient conversion between quasi-transverse electromagnetic (TEM) waves and transverse magnetic (TM) polarized SSPPs waves are achieved by loading the novel transition structures. The designed filter can suppress unnecessary radiation loss and increase transmission efficiency. More importantly, the filter size is 47.52 mm $\times7.47$ mm and its length is reduced by at least 61% compared with the other low-pass filters with the same cutoff frequency. This letter has promoted the development and application of SSPPs low-pass filter and related equipment in microwave frequencies.