Coaxial Feed Research Articles

Substrate integrated waveguide differential antenna for full duplex applications

Abstract This paper presents a substrate-integrated waveguide (SIW) differential antenna for full duplex applications. The proposed antenna consists of two square SIW cavities named as outer and inner. The inner cavity is nested into the outer cavity. The outer cavity is differentially excited with a pair of coaxial feed lines, while the inner square patch is orthogonally excited with another pair of differential coaxial feed lines. This orthogonal feeding arrangement results in high isolation between the differential ports. The modified hybrid TE130/310 mode of the outer cavity radiates through a pair of arc-shaped slots at 9.35 GHz, while the TM01 mode of the inner square patch is responsible for the radiations at 8.65 GHz. The proposed antenna prototype is fabricated and measured for validation. Moreover, the designed antenna has a front-to-back ratio better than 22 dB and measured maximum gain values of 6.1 dBi and 7.6 dBi at 8.65 GHz (Port 2 ON) and 9.35 GHz (Port 1 ON), respectively.

A novel millimetre‐wave 2D wide‐angle scanning phased array antenna based on decoupling surface

AbstractThis paper presents a novel millimetre‐wave (mmWave) 2D wide‐angle scanning (WAS) phased array antenna (PAA) based on decoupling surface (DS). The proposed element is a coaxial feeding stacked patch antenna structure that consists of an L‐shape coaxial probe, substrate integrated waveguide cavity, slot layer, radiating patch, DS and defective ground structure. The simulated impedance bandwidth for the element is 14.85% (26.18–30.34 GHz). The simulated result of the 2 × 2 array shows that the designed antenna based on DS achieves an isolation of ≥19 dB within the bandwidth. To validate the scanning capabilities of the proposed antenna, an 8 × 8 PAA prototype is fabricated and measured. The measured scanning range of the prototype achieves a 2D WAS range of ±56° at 27 GHz. The proposed antenna shows great potential in application scenarios, such as automotive radar and satellite communication due to its compact design and ability to achieve WAS in two dimensions.

AcpAS: An Advanced Circularly Polarized Antenna Structure for an Airborne Relay Communication System

The airborne relay system is an important support for improving the stability of communication systems in complex electromagnetic environments. As a key component of the airborne relay system, the antenna needs to have characteristics such as high gain, dual circular polarization, wide beam coverage, and miniaturization. Based on the septum circular polarizer, this paper proposes a high-performance circularly polarized antenna structure suitable for airborne relay systems, named AcpAS. The structure consists of a coaxial feed port, a coaxial-to-waveguide transition, a septum circular polarizer, and a parabolic metal housing. Based on this structure, two antennas operating at 19.6 GHz to 21.6 GHz and 29.2 GHz to 31.2 GHz are designed in this paper. Simulated and measured results show that the two antennas have dual circular polarization characteristics, with beam coverage range of more than ±55° for gains higher than 0 dBi, and the radiation patterns exhibit good symmetry and wide-beam coverage characteristics.

An Electrically Small Patch Antenna Sensor for Salt Concentration Measurement of NaCl Solution.

In this paper, a complementary split-ring resonator (CSRR)-based patch antenna is proposed as a microwave sensor to measure the salt concentration of NaCl solution. The microwave sensor consists of an RF-4 substrate, where a small copper disc is attached on the top as the radiator, a larger copper disc integrated with two CSRRs is attached on the bottom side as the finite ground plane, and a coaxial feeding port is introduced at the ground plane center. During salt concentration sensing, only the top disc is immersed into NaCl solution. The results indicate that the proposed microwave sensor can measure salt concentrations ranging from 5‱ to 35‱ with a maximum sensitivity of 0.367 (kHz/(mg/L)). The proposed microwave sensor is low-cost, low-profile, electrically small, lightweight, and easy to fabricate, and it also can be applied to other solutions' concentration sensing.

Real-time monitoring and control of the layer height in laser metal deposition with coaxial wire feeding using optical coherence tomography

Laser metal deposition (LMD) with coaxial wire feeding is an additive manufacturing technology in which a metal wire is fed into a laser-induced melt pool. The repeated deposition of weld beads allows three-dimensional geometries to be created that can be used for manufacturing, repair, and modification of metal components. However, the process is highly sensitive to disturbances because the fed wire must always be fully melted, and no self-regulating effects as in powder-based LMD exist. The layer height is particularly important for process stability, as even small deviations accumulate over many layers and, ultimately, lead to the termination of the process. Therefore, monitoring and closed-loop control of the layer height during the deposition process are crucial. Due to process emissions, an interruption of the process is usually necessary for the accurate optical measurement of the layer height, which negatively affects the overall productivity. In order to overcome this drawback, an in-axis optical coherence tomography (OCT) sensor was employed in this work, which enabled real-time measurements of the layer height. It was found that positioning the OCT measurement spot as close as possible to the center of the wire provided the highest signal quality. Based on the real-time height data, a closed-loop layer height control was implemented, applying the wire feed rate as the manipulated variable. The experimental results showed that the proposed system was able to compensate for significant disturbances, ensuring dimensional accuracy and process stability.

Effects of Cr3C2 addition on microstructure and corrosion properties of Cr3C2/15–5PH composite coatings on 12Cr13 by laser cladding

The application of laser cladding technology to prepare iron-based composite coatings has significant advantages in improving the surface properties of 12Cr13 stainless steel. 15–5PH composite coatings reinforced with Cr3C2 particles of different contents (0–25 wt%) were prepared on the 12Cr13 surface by the coaxial powder feeding laser cladding system. The microstructure, phase composition, element distribution, corrosion resistance and corrosion mechanism of the composite coatings were analyzed and studied by optical microscope, scanning electron microscope, X-ray energy dispersive spectrometer, X-ray diffractometer and electrochemical workstation. The results indicated that the Cr3C2/15–5PH composite coatings exhibited good macroscopic morphology and dilution rate under appropriate laser cladding process parameters. The addition of Cr3C2 particles changed the main phase from α-Fe to γ-Fe and formed new carbide phases (M7C3 and Cr23C6). The Cr3C2/15–5PH composite coatings exhibited a typical microstructure with rapid solidification characteristics, and the addition of Cr3C2 significantly changed the grain size. The distribution of Fe, Ni, and Cr elements in the composite coatings was uniform, and the relative content of Cr elements increased and remained at high level. The 15-5PH composite coating with 15 wt% Cr3C2 exhibited a lower corrosion current density and higher impedance modulus values. The surface of this composite coating had no obvious corrosion pits, and the passive film effectively retarded the further corrosion by the Cl- ions on the surface during the electrochemical corrosion process. By preparing a 15–5PH composite coating with 15 wt% Cr3C2 on the surface of 12Cr13, the corrosion resistance of the surface can be effectively improved.

Simulation and Design of Three 5G Antennas

In the context of 5G networks, this paper investigates microstrip array antennas and mobile terminal MIMO array antennas. It introduces two innovative designs and, based on these, develops and fabricates a mobile terminal antenna. The first of these designs, a 4 × 4 microstrip array antenna operating in the LTE band 42 (3.4–3.6 GHz), is researched and fabricated and an innovative approach, combining embedded and coaxial feeding methods, is proposed and employed. Measurement results indicate a bandwidth of 373 MHz (3.321–3.694 GHz), achieving a relative bandwidth of 10.7%. The antenna exhibits a high gain of 12.7 dBi, with an undistorted radiation pattern, demonstrating excellent directional characteristics. The second of these designs, a “loop-slot” MIMO antenna designed for 5G mobile devices with metal frames, is investigated. By opening slots in the metal frame and integrating them into the antenna’s feeding structure, the decoupling principle is analyzed from the perspective of characteristic mode theory. This design shares resonant modes between the loop and slot antennas, allowing for the overlapping placement of the two antenna units. Experimental results confirm an isolation level exceeding 21 dB, with significantly reduced dimensions. Finally, an eight-unit MIMO antenna is designed and fabricated for 5G mobile devices with metal frames. Continuous optimization of the “loop-slot” module layout and unit spacing leads to a compact and miniaturized antenna structure. Measurement results show an isolation level exceeding 17 dB, radiation efficiency ranging from 65.8% to 73.7%, and an envelope correlation coefficient (ECC) below 0.03. Finally, an analysis of specific absorption rate (SAR) demonstrates excellent MIMO performance in terms of human body radiation exposure.

Microstructure and Tribological Properties of WC/Ni-MoS2 Titanium-Based Composite Coating on TC4

To improve the mechanical properties of a TC4 surface, TC4 + Ni-MoS2 + xWC (x = 5%, 10% and 15% wt.%) composite coatings were prepared by the coaxial feeding laser cladding technique, and the effect of the WC content on the microstructure and tribological properties of the coatings were investigated using multiple characterization methods. The results indicated that increasing the WC content negatively impacted the forming quality of the coating, but did not change the coating phase which predominantly comprised Ti2Ni, Ti2S, TiC, matrix β-Ti and residual WC. With the addition of WC, TiC exhibited an increase in both quantity and particle size, accompanied by a transition in growth morphology from spherical to petal-like. MoS2 completely dissolved in all coatings and the S element provided by it effectively synthesized a strip-like phase Ti2S which presented a morphology similar to the lubricating phase TiS in the Ti-based melt pool system. The microhardness and wear-resistance of all the coatings were higher than that of TC4 and gradually improved with the addition of WC, which indicated that raising the WC content was conducive to enhancing the mechanical properties of the coatings. The friction coefficient of TC4 was lower than that of the three WC content coatings, indicating that Ti2S was not the lubricating phase. The wear mechanism of all coatings was abrasive wear.

Effects of Y2O3 Content on the Microstructure and Tribological Properties of WC-Reinforced Ti-Based Coatings on TC4 Surfaces

To extend the safety service life of aviation TC4 alloy, the composite coatings of TC4 + Ni-MoS2 + WC + xY2O3 (x = 0, 1, 2, 3, 4 wt.%) were prepared on TC4 by coaxial powder feeding laser cladding technology. The results showed that all the coatings had the same generated phases which mainly consisted of TiC, Ti2Ni, Ti2S, matrix β-Ti, and unfused residual WC. Y2O3 formed co-dependent growth relationships with TiC, Ti2S, and Ti2Ni. Meanwhile, TiC-Ti2S, TiC-Ti2Ni, and Ti2S-Ti2Ni coherent composite structure phases were effectively synthesized in all the coatings. With the increase in the Y2O3 content, the exposed area of the matrix increased and other phases refined progressively. When the Y2O3 content in the coatings were 3 and 4 wt.%, the degree of phase refinement in the coatings was consistent and the phases grew along grain boundaries, but microstructure segregated in the 4 wt.% Y2O3 coating. The microhardness of all the coatings was higher than that of TC4 and decreased with the increase in the Y2O3 content. Higher friction coefficients and lower wear rates both appeared in all the coatings than in the substrate, and they presented a trend of decreased first and then increased with the addition of Y2O3, in which the 3 wt.% Y2O3 coating had the lowest friction coefficient and optimal wear resistance. The research found that the Y2O3 could not change the types of phases in the coatings and could serve as a heterogeneous nucleation center for the refinement of the TiC-Ti2S-Ti2Ni coherent structure phase. Meanwhile, except for the matrix phase, Y2O3 could attract other phases to pinning on the grain boundaries of the coatings. The content of Y2O3 was negatively correlated with the hardness and wear resistance of the coating and it had the optimal tribological properties with the moderate amount of Y2O3. The wear mechanism of all coatings was abrasive wear.

Additive manufacturing of quartz glass using coaxial wire feeding technology

This study explores the process of coaxial wire feeding and melting for quartz additive manufacturing using Direct Energy Deposition (DED). Quartz glass, valued for its excellent mechanical, optical, and thermal properties, is widely used in semiconductor, aerospace, and optical communication industries. Additive manufacturing offers advantages such as cost-effective materials, rapid formation, and customization of structures. However, current methods for additive manufacturing of quartz glass often result in low quality or require complex post-processing, particularly for optical components. In optics, there is a demand for high-quality, straightforward processes, and custom-shaped quartz glass. This article presents a coaxial wire feeding mechanism wherein quartz wire is fed vertically downward along the optical axis into the melting zone created by a CO2 laser, facilitating smooth material deposition onto the molten zone’s surface. Laser power, wire feeding speed, substrate movement speed, and defocusing distance are key factors influencing the quality of single-layer quartz glass formation. Positive defocusing was found to have a beneficial impact on single-layer quartz glass additive manufacturing. Subsequently, optimized process parameters enabled the production of uniformly cross-sectional single-layer quartz glass. Microscopic morphology analysis and temperature field simulation were conducted on the experimental results before and after optimization. Finally, complex quartz glass structures were additively manufactured using the optimized experimental parameters. Results demonstrate that coaxial wire feeding technology has significant potential for achieving uniform dimensions and complex structures in quartz glass additive manufacturing.

Effect of Laser Power on Microstructure and Properties of WC-12Co Composite Coatings Deposited by Laser-Based Directed Energy Deposition.

During the laser-based directed energy deposition (DED-LB) processing, a WC-12Co composite coating with high hardness and strong wear resistance was successfully prepared on a 316L stainless steel substrate by adopting a high-precision coaxial powder feeding system using a spherical WC-12Co composite powder, which showed a large number of dendritic carbides and herringbone planar crystals on the substrate-binding interface. The influences of laser power on microstructural and mechanical properties (e.g., hardness, friction resistance) of WC-12Co composite surfaces were investigated. The results show that laser power has a significant effect on determining the degree of Co phase melting around the WC particles and the adhesion strength between the matrix and the coating. Lower laser power does not meet the melting requirements of WC particles, thus weakening the molding quality of the composite coating. At high laser power, it is possible to dissolve the WC particles and melt the metal powder between the particles, thus improving the material properties. The laser power increased from 700 W to 1000 W and the average hardness of the coating surface gradually increased from 1166.33 HV to 1395.70 HV, which is about 4-5 times higher than the average hardness of the substrate (about 281.76 HV). In addition, the coatings deposited at 1000 W showed better wear resistance. This work shows that the processing parameters during laser-directed energy deposition can be optimized to prepare WC-12Co composite coatings with excellent mechanical properties.

Design and feed two models for microstrip antenna in two different feed methods and compare their properties

In any wireless communication, the antenna plays a very important role. The need in this technology is to reduce the size of the antenna, weight, and cost with a low profile, high performance, and low return loss (RL), which is what researchers are striving for. This paper attempts to implement a rectangular microstrip patch antenna and analyze its performance for different types of feeding techniques. In this research, we designed two thin slice antennas fed in two different ways, using FR4 epoxy as an insulating substrate with a dielectric constant of 4.3. Copper was used as a conducting material for the radiating patch and the transmission line, with nearly similar geometrical dimensions. The first antenna has dimensions of (31x 26x1.6) m3 and the second antenna has dimensions of (30x27x1.6) m3. The first antenna operates with a coaxial probe feed technique and the second one operates with a microstrip line feed technique. The return loss for the first antenna we obtained is -26.0113dB with a standing wave voltage ratio of 1.1053 at a frequency of 3.59GHz, and -24.743GHz with a standing wave voltage ratio of 1.8908 at a frequency of 5.529GHz. The return loss for the second antenna is -27.468dB with a standing wave voltage ratio of 1.0884 at a frequency of 3.45GHz. The design, simulation, and inclusion of shapes and graphics for both antennas were done using the CST (Computer Simulation Tool) program

MINIATURIZATION OF STACKED WEARABLE ANTENNA FOR 5G APPLICATIONS

Wearable antennas have significantly expanded the capabilities of electronic devices, as they can now be seamlessly integrated into clothing for user convenience. The advent of 5G has opened up possibilities for enhanced functionality, necessitating compact antennas with high gain for efficient data transmission. In this paper, a sub-6GHz 5G stacked wearable antenna is proposed. The choice of a rectangular patch structure was made for its simplicity and ease of fabrication. A comprehensive analysis of antenna design, progressing from a single layer to a multilayer configuration is explained. The antenna was designed using 1mm felt and Shieldit Super conductor, with a 50 Ω coaxial feed. The proposed stacked three-layer antenna, with substrate dimensions of 44 x 44 mm², achieves a gain of 2.7 dBi. Stacking the substrate and patch layer improves the antennas’ performance, especially the impedance bandwidth and gain. On top of that, the antenna dimensions were reduced to 57% while maintaining its performance. Bending tests conducted in both X- and Y-axes demonstrate that the antenna's performance remains within an acceptable range. Although the resonating frequency shifted to 3.4 GHz in 3 layers during bending in Y-axis, the gain was kept to 1.8dBi. Both measured and simulated results exhibit good consistency, with a slight shift observed in the case of the three-layer structure.

Processing correlations of laser direct energy deposited Inconel718 based on multi-field numerical simulation

Laser direct energy deposited (LDED) Inconel718 always have problems of non-uniform temperature distribution because of the complex flow of molten pool and layer-by-layer fabrication characterization which directly affected the microstructure and mechanical properties of materials. In this work, Inconel718 revealed a refined grains and a weave structure exhibiting excellent mechanical properties which were superior to those of the conventional casting process were successfully fabricated by adopt a high-precision and intelligent coaxial powder feeding system during the LDED processing. Moreover, based on multi-field numerical simulation method, a two-phase flow model and a transient thermal mechanical deformation model were established to simulate the LDED processing, while takes into account the evaporated mass loss of the inconel718 alloy. The morphology prediction of laser directed energy deposition by multi-physics numerical simulation, the relationship among the laser process parameters, i.e., the laser power, scanning speed and the amount of powder feeding, the temperature filed and the microstructure and mechanical properties of Inconel718 alloy during LDED were investigated and established. The simulated results consistent well with the experimental results. Results shown that the relative density of sample was sensitive to the laser power, the precision and stability of the powder feeding rate. With increasing laser power, the grain size of Inconel718 is refined, and the microhardness and tensile properties of the materials increased. The optimized LDED processing parameters were determined. Evaluating the mechanical properties of the materials LDEDed at a laser power of 600W and a scanning speed of 8.5mms-1 exhibited a high tensile strength of 944±5 MPa and a good elongation of 29 ± 0.5 %. This work suggests that the processing parameters can be optimized to prepare densified materials with excellent mechanical properties.

Fabrication and characterization of self-lubricating anti-wear 316L stainless steel/h-BN composite coatings on Q235 substrate via laser cladding

This paper presents the fabrication and characterization of self-lubricating, anti-wear 316L stainless steel composite coatings on a Q235 substrate using 316L stainless steel powders and nanoscale hexagonal boron nitride (h-BN) ceramic particles via coaxial powder feeding laser cladding. The influence of process parameters on cladding quality and geometry, and the impact of h-BN contents (2 wt% and 5 wt%) on the microstructure and mechanical properties of the coatings were studied. Optimal process parameters for 316L/5wt%BN coatings were identified: a powder feeding rate of 3–4 rpm, a laser power of 2200–2400 W, a scanning speed of 4–5 mm/s, and an overlapping rate of 40 %. Microstructural analysis showed a smooth surface without cracks or pores. X-ray diffraction revealed intermetallic compounds such as CrB, Cr2N, Fe3N, BN, and γ-(Fe, Ni). The inclusion of h-BN nanoparticles enhanced grain refinement, significantly increasing microhardness. Coatings with 5 wt% h-BN achieved an average microhardness of 438.8 HV10, 2.5 times higher than the substrate and the 316L stainless steel. Additionally, h-BN reduced friction coefficients, leading to substantial wear reduction. The 316L/5 wt% h-BN sample experienced only 4.2 mg of wear, 45.16 % of the substrate’s wear. These findings highlight the beneficial effects of h-BN nanoparticles on 316L stainless steel coatings, enhancing wear resistance, hardness, and overall performance.

Microstructure and Wear Resistance of In Situ Synthesized Ti(C, N) Ceramic-Reinforced Nickel-Based Coatings by Laser Cladding.

In recent years, laser cladding technology has been widely used in surface modification of titanium alloys. To improve the wear resistance of titanium alloys, ceramic-reinforced nickel-based composite coatings were prepared on a TC4 alloy substrateusing coaxial powder feeding laser cladding technology. Ti (C, N) ceramic was synthesized in situ by laser cladding by adding different contents (10%, 20%, 30%, and 40%) of TiN, pure Ti powder, graphite, and In625 powder. Thisestudy showed that small TiN particles were decomposed and directly formed the Ti (C, N) phase, while large TiN particles were not completely decomposed. The in situ synthetic TiCxN1-x phase was formed around the large TiN particles. With the increase in the proportion of powder addition, the wear volume of the coating shows a decreasing trend, and the wear resistance of the surface coating is improving. The friction coefficient of the sample with 40% TiN, pure Ti powder, and graphite powder is 0.829 times that of the substrate. The wear volume is 0.145 times that of the substrate. The reason for this is that with the increase in TiN, Ti, and graphite in the powder, there are more ceramic phases in the cladding layer, and the hard phases such as TiC, Ti(C, N) and Ti2Ni play the role in the structure of the "backbone", inhibit the damage caused by micro-cutting, and impede the movement of the tearing point of incision, so that the coating has a higher abrasion resistance.

Influence of Cu addition on the microstructure and tribological properties of Ti-based laser cladded composite coatings on TC4

Ti-based composite coatings using TC4/Ni60/Cu mixed powders with of 0, 5, and 10 wt% Cu additions were prepared on TC4 by coaxial powder feeding laser cladding to investigate the effects of the addition of Cu on their microstructure and tribological properties. Multiple technical methods were performed for characterization, and the results revealed that TiC, TiB, Ti2Ni, and α-Ti precipitated in all coatings. As Cu added, the coating microstructure was gradually refined, and quasi-nanometer Ti3Cu was synthesized in the 5 and 10 wt%-Cu coatings where the Ti3Cu-Ti2Ni and Ti3Cu-α-Ti composite structure phase were formed. The microhardness and wear resistance of the three coatings were higher than that of the TC4 substrate and presented a gradual decrease with the Cu additions. The friction coefficients of the above coatings were higher than those of TC4 and generally consistent. The study found that the appropriate Cu addition could enhance the forming quality of the coating, effectively refine the microstructure, improve the uniformity of the microstructure distribution, and reduce fluctuations in microhardness and tribological properties.

Experimental investigation of a dual mode antenna using characteristic mode analysis with enhanced directivity for GSM/5G applications

In this article, a dual-mode, dual-polarized antenna designed using characteristic mode analysis (CMA) is described. An elliptical-shaped patch radiator is chosen with double slits on its minor axis. This design is based on mode separation from the circular patch into the elliptical patch. The suggested antenna geometry has a footprint of 60 mm × 60 mm × 1.6 mm. To design and fabricate the antenna, an FR-4 substrate with a relative permittivity of 4.3 is used, along with copper sheets 0.035 mm thick for the ground plane and the radiating plane. The circular patch has the resonating mode at 1.8 GHz, whereas the elliptical radiator gives different resonant modes at 1.8 GHz and 3.5 GHz. An orthogonal mode is excited with a 50-Ω coaxial feed line at 3.5 GHz by applying a full-wave approach. The antenna gives a −10dB bandwidth of 51 MHz (1.77–1.82 GHz) centered at 1.8 GHz and a bandwidth of 210 MHz (3.37–3.58 GHz) centered at 3.5 GHz. The working principle is explained through modal analysis and characteristic angles. This dual-band antenna covers a 1.8 GHz GSM band with horizontal polarization and a 3.5 GHz 5G service with vertical polarization. Peak gain attained with these bands is 5.9 dBi and 7.1 dBi, respectively. A CST full-wave simulator is used for the simulations. As a result of the antenna, radiation is stable and enhanced. Compared to measured results, simulation results are close to reality. The characteristic mode analysis (CMA) provides an in-depth look into different operating modes on the antenna in contrast with the conventional method, which relies on the simulated current distribution to verify functionality.

Design of TE-polarized resonant Bessel-beam launchers for wireless power transfer links in the radiative near-field region

Abstract Resonant Bessel-beam launchers (BBLs)are radiating devices constituted by a cylindrical metallic cavity with a partially reflecting sheet (PRS) on top. Millimeter-wave resonant BBLs typically exhibit transverse magnetic (TM) polarization due to the use of coaxial probes as feeders and homogenized metasurfaces as PRS. Launchers showing either a purely transverse electric (TE) or a hybrid (quasi-TE) polarization have recently been proposed for realizing wireless power transfer (WPT) links in the radiative near-field region at millimeter waves. The former are obtained by means of a radial slot array as a feeder and a homogenized metasurface as a PRS. The latter are obtained by using a loop antenna as a feeder and an annular strip grating in the homogenization limit as radiating aperture. In this work, based on an original semi-analytical model, such a metasurface is demonstrated to show a dichroic behavior. This interpretation explains the improvement in terms of polarization purity with respect to more nondichroic conventional homogenized metasurfaces. The behavior of the annular strip grating under a pure TM polarization is tested with a coaxial feeder, whereas its behavior under a pure TE polarization is tested by means of the radial slot array feeder. Results confirm the validity of the proposed analysis, which is finally exploited to evaluate the WPT performance.

High-gain TM11 mode equilateral triangular patch antenna with shorting pins and triangular short horn

Abstract Normally, the reported gain of the microstrip patch antenna is within 8 dBi. Using properly located three shorting pins on three bisectors, the present work reports a method to convert the non-radiating TM11 mode of equilateral triangular patch antennas (ETPAs) to a deformed TM11 radiating mode. The boresight gain of ETPA operating in TM11 mode is enhanced from −10.75 to 12.1 dBi at 5.43 GHz. The boresight measured gain is further enhanced to 14.2 dBi at 5.52 GHz by using a triangular surface-mounted short horn (SMSH) of about ${{\lambda }}/5$ height. The aperture efficiency of the ETPA with the shorting pins is 84.2%. The aperture efficiency is further improved to 94.2% using the SMSH. The measured boresight cross-polarization and side-lobe level are −40 and −29 dB, respectively. The nature of the electricfield and surface current distribution is analyzed, using both the characteristic mode analysis method and high-frequency structure simulator, to understand the role of shorting pin and coaxial feed in converting the non-radiating TM11 mode to the radiating mode. A systematic design process also is presented for a fast design of shorting pin-loaded ETPA on the suitable substrate at a specified frequency.