T-shaped Strip Research Articles

Experimental study on hysteretic behavior of energy dissipation braces with bending plates and perforated shear plates

The shear plates had been adopted in the energy dissipation braces, but the ductility of energy dissipation braces with shear plates was poor. In this paper, a new-type bending plate-strip coupling energy dissipation brace (BSEB) with bending plates and perforated shear plates was proposed, and the strips included non-uniform strips, stiffening non-uniform strips, and T-shaped strips. The hysteretic behavior of five BSEBs was investigated through a quasi-static test. The experimental parameters included boundary condition, arrangement of perforated shear plates, and material. The experimental results indicated that the initial stiffness of BSEBs with pinned connection was significantly lower than that with bolted connection; The influence of arrangement of perforated shear plates on seismic performance of BSEBs could be little; The BSEB with perforated shear plates fabricated by stainless steel had higher initial stiffness and ultimate bearing capacity, and lower energy dissipation capacity and ductility; The fracture occurred in stiffening non-uniform strips, T-shaped strips, non-uniform strips, and bending plates in turn, and plastic strain occurred in stiffening non-uniform strips, non-uniform strips, T-shaped strips, and bending plates in turn. Finally, a few formulas for predicting the yield bearing capacity of a BSEB were developed and verified.

A T-Shaped Strips Loaded Wideband Filtering Patch Antenna With High Selectivity

A T-Shaped Strips Loaded Wideband Filtering Patch Antenna With High Selectivity

A compact bent microstrip-based wideband millimeter wave MIMO antenna for 5G applications

Abstract This paper proposes a wideband four-element multiple-input multiple-output (MIMO) antenna operating in the millimeter-wave frequency band for 5G communications from 24.37–39.44 and 45.09–50.62 GHz. The antenna design has been realized using Rogers 5880 substrate and consists of a T-shaped strip that is attached to the top of a 50 Ω feeding line. Two microstrip lines are affixed at the terminal points of T-shaped strip and bent toward the feeding structure. These bent strip lines are then extended by joining two additional L-shaped microstrip lines. On the back, there is a partial defective ground plane featuring a rectangular slot and a thin strip line located at its center. The dimensions of the proposed single element and MIMO antenna are 0.933λ × 0.933λ × 0.024λ and 1.865λ × 1.865λ × 0.024λ, respectively (at 28 GHz), while the edge-to-edge distance between the radiation elements of the MIMO antenna is 4.0 mm. The design incorporates an efficient passive fan-shaped decoupling structure to decrease coupling between antenna elements. Simulations and experimental results show good agreement with each other. For all resonant frequencies the measured peak gain is greater than 4.85 dBi, radiation efficiency is over 90%, diversity gain is greater than 9.5, ECC is less than 0.025, TARC is less than -10 dB and CCL is below 0.4 bits/s/Hz. The proposed MIMO antenna, with its wide bandwidth, high gain, high inter-port isolation, and high efficiency characteristics, can be used for 5G wireless communication applications.

A Dual Port Hybrid Super-wideband MIMO Antenna with Diminished CCL and High BDR for IoT Applications

In this work, a simple hybrid dual port skull-shaped super wideband Multiple Input Multiple Output (MIMO) antenna with improved isolation is designed and analyzed. Each antenna element consists of a skull-shaped radiator along with a rectangular notched chamfered Defective Ground Plane structure (DGS). The proposed antenna’s impedance bandwidth and radiation characteristics are improved by the triple elliptical inclined slot and DGS together. To accomplish the proposed MIMO configuration, the antenna elements are further organized in a linear arrangement. Deteriorated isolation characteristics, which are the key bottleneck for such MIMO schemes, are significantly improved in the proposed design by using a corrugated T-shaped strip decoupling plane. This 2-port MIMO antenna is placed on top of a glass epoxy FR4 substrate and has an overall dimension of 45 × 50 × 0.787 mm3 (0.20λ × 0.19λ × 0.003λ). The proposed MIMO antenna is fabricated and the experimental results are verified with the simulation results. The results indicate that the proposed antenna covers an operational bandwidth of 48.75 GHz (1.25–50 GHz) with a fractional bandwidth of 190.24% and offers an isolation of less than −20 dB throughout the frequency range of operation. The proposed MIMO has an extremely high bandwidth dimension ratio (BDR) of 5092 among the reported antennas. An optimal performance has been achieved with a lower value of Envelope Correlation Coefficient (ECC) ≤ 0.02, high multiplexing efficiency, extremely lower Channel Capacity Loss (CCL) of 0.2, and omnidirectional radiation characteristics. These design metrics show the potential of our antenna to operate for eMBB (Enhanced Mobile Broadband) applications which includes 5G, Augmented reality, and etc.

Mutual Coupling Reduction in Dual-Band MIMO Antenna Using Parasitic Dollar-Shaped Structure for Modern Wireless Communication

A dual-band Multiple Input Multiple Output (MIMO) antenna with low mutual coupling is analyzed and studied for Fifth Generation (5G) Sub-6 GHz and Wireless Fidelity (Wi-Fi) 6E frequency-band applications. Each of the identical monopole radiators consists of a rectangular patch, inverted-E, and asymmetrical T-shaped strip to generate 5G Sub-6 GHz and Wi-Fi 6E frequency bands. The deployment of the radiators horizontally with end-to-end separation of 5mm makes the antenna compact with an overall dimension of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$45\times 30$ </tex-math></inline-formula> mm2 ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.37\lambda \times 0.25\lambda $ </tex-math></inline-formula> for <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda $ </tex-math></inline-formula> at the lower resonating frequency of 2.5GHz). The antenna achieves measured impedance bandwidths of 2.39-2.57 GHz and 3.82-6.95 GHz, respectively, at two resonating frequencies of 2.5 GHz and 4.5 GHz. A Parasitic Dollar Shaped Structure (PDSS) introduced between the two monopole radiators to suppress the surface waves of each monopole reduces the measured mutual coupling up to -15 dB throughout the operating band. Furthermore, the measured gain, radiation efficiency, Envelope Correlation Coefficient (ECC), and Diversity Gain (DG) values remain in good agreement with simulated values and are well within the minimum limit set by industry standards. These results affirm the applicability of the MIMO antenna for 5G and Wi-Fi 6E frequency bands.

A circular monopole antenna with uniquely packed quad T-shaped strips for WLAN/WiMAX application

Abstract This paper presents a circular monopole antenna with uniquely packed quad T-shaped strips etched on FR4 epoxy substrate having material permittivity 4.4, loss tangent 0.02, and thickness 1.6 mm. The 3.5 GHz band is achieved through this arrangement, which has return loss less than −10 dB while maintaining VSWR &lt;2. It provides a peak gain of 2.65 dBi at 3.5 GHz and average gain of 2.52 dBi in the entire operating frequency band. The radiation pattern is almost omnidirectional in E plane and bidirectional in H plane. The proposed antenna has a compact size of 41.25 mm × 30.55 mm. The simulated results of S11 parameters, gain, VSWR, radiation pattern, and efficiency are studied and verified with the measured results of fabricated antenna as well as its equivalent lumped circuit model. Investigation shows that the proposed antenna can be employed for WLAN/WiMAX applications efficiently.

A polarization-insensitive, wide-angle dual-band tunable graphene metamaterial perfect absorber with T-shaped strips and square ring

Metamaterial perfect absorbers play an essential role in many optoelectronic devices. In this paper, a dual-band tunable metamaterial perfect absorber based on graphene is proposed. The simulation results present that under normal incidence two absorption peaks of 99.9% and 99.9% occur at the frequencies 1.69 THz and 4.30 THz, respectively. Impedance matching theory is employed to elaborate this dual-band perfect absorption phenomenon. While at oblique incidence, the absorption of the absorber remains more than 90% over a wide incident angle from 0° to 75° for the transverse electric (TE) polarization and 60° for the transverse magnetic (TM) polarization separately. Furthermore, it is also independent to the polarization angles. In addition, the effects of different geometrical parameters and the chemical potential of graphene on the resonant frequencies are investigated in detail. The two peaks of the absorber can be dynamically tuned by the variation of the chemical potential of graphene. Due to its good performances, the designed metamaterial perfect system has great potential applications in biosensing, photodetectors, stealth, and imaging devices.

Stacked T-Shaped Strips Compact Antenna for WLAN and WiMAX Applications

A compact triple band antenna with stacked T-shaped strips inside a rectangular ring monopole has been proposed. This novel structure with a slot in the defected ground achieves triple band opration i.e. 2.47–2.77 GHz, 3.3–3.7 GHz and 5.10–6.62 GHz. These bands find application in important wireless communication standards like WiMAX (3.3–3.8 GHz, and 5.25–5.85 GHz, WLAN (2.4 G-2.5 GHz, 5.1–5.3 GHz, and 5.72–5.85 GHz). The antenna is printed on a FR-4 substrate with an overall dimension of 33 times 17 times 1.6 ;{text{mm}}^{3}. An impedance bandwidth of 11% (2.47–2.77 GHz), 11% (3.3–3.7 GHz) and 25% (5.10–6.62 GHz) is obtained. A good conjunction between the simulated and measured results is inferred from the antenna design analysis.

Performance of Reconfigurable Antenna Fabricated on Flexible and Nonflexible Materials for Band Switching Applications

In this article, a novel frequency slot-based switchable antenna fabricated on flexible and nonflexible materials is presented for suitable reconfigurable radiations of Bluetooth, WiMAX, and upper WLAN applications. Initially, the performance of this structure was simulated using a CSTTM simulator and evaluated experimentally using a nonflexible FR4 structure. The same antenna was implemented on a flexible (jean) substrate with a relative permittivity of 1.7. The proposed textile antenna prototypes were fabricated by optimal dimensions of an E-shaped slot with a variation on the shape of the ground layer, integrated using a crossed T-shaped strip with ON/OFF switchable state operations. The proposed antenna prototype is compact (20 × 20 mm2), providing switchable radiations with tri bands, has frequencies ranged at 2.36–2.5 GHz for Bluetooth, 3.51–3.79 GHz and 5.47–5.98 GHz for the distinct bands of WiMAX and WLAN, respectively, as well as part of UWB operations.

Low-RCS feature for UWB antenna with band-notch characteristics

This paper presents a new technique to reduce radar cross-section (RCS) of dual-band antennas. In order to show that the proposed method can be applied in various types of monopole antennas, two different patch antennas are designed one of which is fabricated. The primary model of the fabricated antenna without modification is composed of a circular radiator with two pairs of T-shaped strips. To reduce the RCS of the antenna, a half of its radiator that is not connected to the feed line is removed with its substrate. A perfect electric conductor (PEC) wall is designed and located in front of the remained half patch to generate an image of it. The results indicate that the proposed structure offers an omni-directional radiation pattern over a wide frequency range and a very wide impedance bandwidth with a WLAN band rejection as well as an in-band and out-of-band RCS reduction.

Design and development of a singly-fed circularly polarized rectangular dielectric resonator antenna for WiMAX/Satellite/5G NR band applications

A circularly polarized rectangular dielectric resonator antenna (DRA) has been designed (3.7–4.2 GHz) for WiMAX, satellite, and sub-6 GHz 5G NR band communications. A new T-shaped monopole has been used to excite the rectangular DRA. Using proposed conformal metal strip, the higher-order degenerate modes TEδ13x and TE1δ3y have been excited to achieve circular polarization (CP) with improved gain. Further, the bandwidths enhancement has been achieved by placing a parasitic patch of optimized height and width at a specific distance from T-shaped strip on DRA surface to cover the desired frequency band. A signaficant enhancement of ~73% in the impedance-matching bandwidth and ~75.5% in axial ratio (AR) bandwidth has been achieved. The |S11|≤10 dB over a wide bandwidth of ~17.3% has been offered by the antenna. A broad axial ratio bandwidth of ~17.2% along with a useful gain of ~6.32 dBic has been provided by the antenna. The antenna designing and optimization has been carried out using CST® Microwave Studio. A reasonable agreement between simulated and measured results has been observed.

1-D Electronic Beam-Steering Partially Reflective Surface Antenna

A 1-D electronic beam-steering partially reflective surface (PRS) antenna using a new reconfigurable PRS unit cell is proposed in this paper. The proposed work addresses the challenge to achieve a large beam steering angle with small gain variation and a small number of active/lumped elements by using a reconfigurable PRS superstrate only. The PRS unit cell consists of two back-to-back T-shaped strips with one PIN diode inserted between them and a pair of trapezoid patches (a rectangular patch and a pair of triangle parasitic patches). Beam steering is achieved by controlling the different states of PIN diodes. Thanks to the trapezoid patches, the proposed unit cell can generate a larger phase difference between different states, thereby leading to a larger beam steering angle. Furthermore, due to the addition of more degrees of freedom in the proposed unit cell, the phase difference can be easily manipulated. Moreover, since the T-shaped strips in each unit cell is connected with adjacent ones, the biasing network is very simple without needing a large number of lumped elements and dc biasing lines. The beam steering property is analyzed by using phased array theory. An antenna prototype with a main beam direction towards 0°, -18° and 18° operating at 5.5 GHz in the H-plane is fabricated and measured. Good agreement between the predicted simulation and measurement results for the input reflection coefficients and radiation patterns is achieved, which validates the feasibility of the design. The measured realized gains are over 11 dBi for all states with a 0.8 dBi gain variation.

Asymmetric U-shaped printed monopole antenna embedded with T-shaped strip for bluetooth, WLAN/WiMAX applications

In the present paper, a microstrip line fed compact monopole printed antenna is designed for Bluetooth, WLAN and WiMAX applications. The designed antenna has a compact size of dimensions 34 × 20 × 1.6 mm3. The proposed antenna comprises asymmetric U-shaped radiator embedded with a T-shaped strip in the middle of the patch. Stair shaped defected ground plane with rectangular slit is used for the bandwidth enhancement. The antenna design achieves the maximum impedance bandwidth of 107.35% (2.27–7.53 GHz). Radiation efficiency is higher than 70.0% throughout the entire operating band. The simulated and measured realised antenna gains are in good agreement and vary in the range of 2.14–4.83 and 2.20–4.91 dBi respectively. Radiation patterns are almost omnidirectional in H-plane and bidirectional pattern in E-plane. The antenna characteristics are calculated using CST Microwave Studio and the results are compared with the measured results.

Design of reconfigurable monopole antenna with switchable dual band-notches for UWB applications

AbstractA compact printed reconfigurable monopole antenna with switchable band-notches is designed and manufactured. The proposed antenna mainly consists of a disc-like radiator with two pairs of T-shaped strips protruded inside a rectangular aperture. Five PIN diode switches are employed to bridge or open the slots, which allow the antenna to be configured into three different structures functioning as an ultra-wideband (UWB) antenna, or an antenna with notched frequencies at WLAN or WiMAX band. Design and optimization of the antenna are done using CST Microwave Studio. After fabrication on an FR4 substrate with dimensions of 35 mm (width) × 41 mm (length) × 1.5 mm (thickness), numerical and experimental results of the proposed reconfigurable antenna are presented and discussed. The experimental results confirm the design as a good candidate for UWB applications.

FREQUENCY RECONFIGURABLE PATCH ANTENNA FOR 4G LTE APPLICATIONS

A compact printed multi-band frequency reconfigurable patch antenna for 4G LTE applications is presented in this paper (50 x 60 x 1.6 mm3). The antenna consists of W-shaped and Inverted-U shaped patch lines connected in a Tree-shape on the front side of the antenna. The back-side of the antenna contains a 90°-tilted T-shaped strip connected with an Inverted-L shaped strip which is shorted with a patch on the front side for increasing the electrical length to cover lower frequency bands. Frequency reconfigurability is achieved by inserting three switches i.e., PIN diodes. The most critical part of this work is the designing of RLC-based DC line circuits for providing the DC biasing to the PIN diodes used as switches and inserting them at optimum locations. This antenna is reconfigurable among eight different 4G LTE frequency bands including 0.9 GHz, 1.4 GHz, 1.5 GHz, 1.6 GHz, 1.7 GHz, 1.8 GHz, 2.6 GHz, 3.5 GHz and WLAN band 2.5 GHz. The antenna exhibits different radiation patterns having a different direction of peak gain at different frequencies and for different switching combinations. The antenna is simulated with CST, and a prototype is fabricated to compare the measured and simulated results with good accuracy.

Compact Tri-Band Notched Characteristics UWB Antenna for WiMAX, WLAN and X-Band Applications

Compact microstrip-fed printed monopole antenna with triple band-notched characteristics is suggested for ultra-wideband (UWB) applications. The antenna is constructed of a conventional rectangular microstrip patch antenna with partial ground plane and T-shaped strip employed in the ground plane as well as an inverted Ω- and L-shaped slots incorporated within the radiated element. The notched functions are created by the inverted Ω- and L-shaped slots, which are realized for WiMAX (from 2.69 to 4.5 GHz) and WLAN (from 5.49 to 6.37 GHz). The T-shaped parasitic strip generates the third notch for the X-band uplink satellite communication (from 8.15 to 9.61 GHz). The measured operating -10 dB bandwidth of the proposed antenna extends from 2.39 to more than 18 GHz except at the notched bands. The prototype antenna has a total area of 20×20×1.6 mm3. Electromagnetic (EM) simulations are carried out using 3D full-wave FEM-based simulator. EM simulation results are in good agreement with measurement results. The radiation pattern of the proposed antenna is nearly Omni-directional over the whole targeted band.

G‐shaped band‐notched ultra‐wideband MIMO antenna system for mobile terminals

Low-profile band-notched G-shaped ultra-wideband (UWB) multiple input multiple output (MIMO) antenna design for mobile terminals has been presented. In this context, two UWB MIMO antenna systems have been designed: The first is with square elements and the second is with G-shaped elements. An MIMO antenna with two symmetrical square elements each of 8 × 8 mm 2 operating between 2.2 and 13.3 GHz was firstly designed for the UWB applications. Each square element was fed through a 50-Ω microstrip transmission line (MTL). A thin strip line was designed at the end of MTL to provide impedance matching. Although the isolation level between the elements was satisfactory for efficient MIMO implementation, a T-shaped strip on the ground was employed to further improve the isolation for low frequency. The frequency range of 4.4-6.2 GHz which is an important band of wireless local area network (WLAN) standard was then notched by forming a G-shaped structure on the square element. The performance of G-shaped antenna system was studied in terms of important antenna characteristics and MIMO parameters. The results demonstrate that the G-shaped MIMO antenna has nearly omnidirectional patterns, stable gain and good diversity performance besides having low-profile elements.

Three-dimensional interaction diagram for the undrained capacity of inverted T-shape strip footings under general loading

This paper presents new solutions of a three-dimensional (3D) interaction diagram for the undrained capacity of inverted T-shape strip footings under general loading. The two-dimensional plane strain finite-element analysis was employed to determine the stability of this problem. Parametric studies were performed to study the interactions of the combined vertical load (V), horizontal load (H) and bending moment (M) that were applied on top of the inverted T-shape footing. The combined action of vertical forces included both tensile (upward) and compressive (downward) loadings. The results of these analyses were summarised in terms of the dimensionless factors for V, H and M. Failure mechanisms associated with different locations on the 3D interaction diagram were compared and discussed. A closed-form approximate solution of the 3D interaction diagram for inverted T-shape strip footings under the V–H–M loading was proposed and compared with the finite-element solutions.

Broadband Circularly Polarized 2 × 2 Antenna Array with Sequentially Rotated Feed Network for C-Band Application

In this paper, a unique broad-band circularly polarized antenna array with sequentially rotated feed-network for C-band applications is proposed. In order to, implement presented array element, a novel and miniaturized square slot antenna, with one pair of attached L-shaped and a T-shaped strips at ground surface, for decreasing cross polarization purity, is presented. Two L-shaped strips with different length are inserted at slot antenna’s patch to enhance impedance matching. The symmetric coplanar waveguide is used for feeding the slot element. The antenna element obtains a 3 dB axial ratio bandwidth from 5.85 to 6.25 GHz. For further improving of radiation attributes, elements in 2 × 2 array are linked together by sequentially rotated feed to achieve wider axial ratio and impedance matching bandwidths. The main advantage of feed network is designed in a way that to have less coupling effect between elements. The axial ratio (AR) and impedance bandwidths of array is from 4.9 to 6.45 GHz (for AR <3 dB) and 4 to 8.1 GHz (for VSWR <2), respectively. Simulation and measurement results validated the proposed array design.

Small Square Reconfigurable Antenna with Switchable Single/Tri-Band Functions

A novel frequency reconfigurable slot antenna for suitable switchable radiations at WLAN and a tri-band at Bluetooth, WiMAX and upper WLAN applications is designed and fabricated. Switchable frequency responses are achieved by implementation of a PIN diode within the antenna ground plane. The antenna structure consists of a square radiation patch with an E-shaped slot, a modified ground plane with an inverted T-shaped strip that acts as a parasitic stub and two parallel slots and a protruded strip which is connected to the parasitic stub with a PIN diode. The presented antenna has a compact size of 20 × 20 mm 2 while providing switchable radiations at 2.36-2.5 GHz Bluetooth, 3.51-3.79 GHz WiMAX, and 5.47-5.98 GHz WLAN when the diode is ON and 5.04-6.13 GHz WLAN when the diode is OFF.