Composite Antenna Structure Research Articles

FEA Modeling and Verification of Structural Property of Large Sandwich Composite Antenna Structure

The composite sandwich structure applied to the subject of this study is an effectively designed structure that enhances the specific stiffness of the panel. It features CFRP face sheets, which are strong under tensile and compressive loads, on both sides of an aluminum honeycomb core, a porous structure that is weak in tension and compression but strong in bending. The subject of this study weighs over 4 tons and possesses the largest weight and size among composite antenna structures in the country. Due to the lack of many references for large composite structures, accurate material properties are obtained through specimen tests, and the finite element analysis model is experimentally validated to ensure it accurately represents the actual structure. Finally, the structural robustness is verified through the structural analysis results of the validated model.

FSS embedded high gain ‘N’ shaped miniaturized broadband antenna

This research work represents a broadband (3.3 GHz − 17.85 GHz) high gain miniaturized (16 mm × 24 mm × 1.6 mm) microstrip patch antenna. Initially multiband property is achieved through ‘N’ shaped radiating patch surface and ‘I’ shaped ground plane surface. Finally broadband property is attained through better impedance matching by modifying feeding structure with a single step matching staircase structure. The presented antenna shows large −10 dB impedance bandwidth of 14.55 GHz with a percentage bandwidth of 138 %, Bandwidth Dimension Ratio (BDR) of 2970 and a peak gain of 4.45 dBi at 9.5 GHz. By embedding FSS (Frequency Selective Surface) structure having FSS unit cell dimension of 13 mm × 13 mm × 1.6 mm with the antenna at suitable distance, antenna gain has been elevated successfully across the entire operating frequency range (3.25 GHz–17.8 GHz). FSS coupled antenna exhibits highest gain improvement of 7.5 dBi at 3.5 GHz and peak gain of 9.1 dBi at 9.3 GHz. The FSS integrated antenna structure operates with elevated gain (peak gain of 9.1 dBi at 9.3 GHz) across the entire operating frequency range (3.25 GHz–17.8 GHz). All inclusive volume of the presented FSS coupled antenna is 52 mm × 52 mm × 21.2 mm, which can be successfully utilized in high gain broadband wireless applications. The antenna patch area miniaturization is calculated as 65 % with respect to lowest frequency of operation. The proposed FSS and antenna are developed and simulated by utilizing CST Studio Suite Software and equivalent circuit of the presented antenna is simulated utilizing ADS software. Both FSS and antenna are fabricated using inexpensive FR 4 substrate (1.6 mm thick, relative dielectric constant of 4.4 and loss tangent of 0.02) and Standard Microwave Test Bench is used to validate the antenna and composite antenna structure simulation results.

Loop antenna over a conducting cone with a spherical cap

A composite antenna structure consisting of a conducting cone loaded with a spherical cap is designed and analysed, considering all eigenmodes in the antenna structure. The configuration is used to enhance the impedance match to a loop antenna located above the cone tip. Matching characteristics to the loop are examined over a wide range of loop radius and loop location. It is found that the matching to the loop can be significantly enhanced over a wide range of parameter values, yielding a greater flexibility in design than the loop-around-the-cone structure presented earlier with the conducting cone body inside the loop. The structure also enables placement of the loop at a greater height than the loop-around-the-cone configuration, potentially improving the efficiency of signal transmission/reception or reducing scattering from the vehicular body. The mutual coupling effect of a parasitic loop placed adjacent to the primary loop is also analysed. The radiation characteristics are also evaluated.

Dual-band circularly polarized dielectric resonator antenna for wireless applications

This letter investigates an integrated antenna configuration for WLAN/WiMAX applications. The proposed composite antenna configuration is simply the grouping of ring dielectric resonator along with reformed square-shaped slot antenna. Three significant characteristics of proposed article are: (1) aperture act as magnetic dipole and excite HE11δ mode in ring dielectric resonator antenna; (2) reforming of square aperture generates orthogonal modes in ring DRA and creates CP in lower frequency band; (3) annular-shaped Microstrip line along with reformed square aperture creates CP wave in upper frequency band. With the purpose of certifying the simulated outcomes, prototype of proposed structure is fabricated and tested. Good settlement is to be got between experimental and software generated outcome. Experimental outcomes show that the proposed radiating structure is operating over 2 frequency bands that is, 2.88-3.72 and 5.4-5.95 GHz. Measured 3-dB axial ratio bandwidth in lower and upper frequency band is approximately 9.52% (3.0-3.4 GHz) and 5.85% (5.64-5.98 GHz), respectively. These outcomes indicate that the proposed composite antenna structure is appropriate for WLAN and WiMAX applications.

Compact Broadband Omnidirectional Radiation Pattern Printed Dipole Antenna Incorporated With Split-Ring Resonators

A broadband, low-profile, compact, and cost-effective antenna consisting of a printed dipole loaded with split-ring resonators (SRRs) is presented. The antenna consists of two identical printed SRRs, each enclosing an arm of a printed dipole element. Each SRR and the center-fed half-wavelength dipole element are printed on the top and bottom sides of a thin dielectric substrate. The dipole is excited by a coaxial feed, while the SRRs are electromagnetically coupled to the dipole. The dipole, in conjunction with the SRRs, generates three resonant modes with stable omnidirectional radiation patterns. These resonances interact to provide broadband characteristics, that is, a measured impedance bandwidth covering 1.32–2.46 GHz for a reflection coefficient of less than −10 dB. The functionalities, mechanisms, and modes of operation of the composite antenna structure are discussed in relation to both the dipole and the SRRs. A prototype is fabricated and measured in order to validate the antenna design. It is computationally and experimentally confirmed that the antenna demonstrates broadband characteristics as well as a stable gain with non-deteriorating omnidirectional radiation patterns. The compact antenna, which has the overall dimensions of 9.6 mm $\times$ 74.4 mm $\times$ 0.508 mm ( $0.06\lambda \times 0.469\lambda \times 0.0032\lambda$ at 1.895 GHz), has a measured fractional bandwidth of 60.31%, an omnidirectional radiation pattern with a gain greater than 1.8 dBi, and a radiation efficiency greater than 88% within a broad impedance bandwidth. The compact size, simple structure, and stable radiation properties of the antenna render it suitable for many wireless communication applications.

Surface enhancement of THz wave by coupling a subwavelength LiNbO3 slab waveguide with a composite antenna structure

Highly intense terahertz electromagnetic field and efficiently surface localized terahertz field in subwavelength volumes are of vital importance for terahertz photonics integration, also will greatly accelerate the development for integrated applications in biochemical sensing, imaging, terahertz spectroscopy, enhancement of nonlinear effects and even quantum research. In this paper, we achieved large terahertz field enhancement and surface field localization through depositing a pair of Au composite antennas on a LiNbO3 subwavelength slab waveguide, which can serve as an excellent on-chip platform for terahertz research and application. The antennas consist of two opposing tip-to-tip triangles separated by a gap, and each triangle combines with a strip antenna. Time-resolved imaging and finite-difference time-domain method were used to resolve the characteristics of the designed antennas experimentally and simulatively. Through these methods, we demonstrated outstanding abilities of the platform: leading to a large electric field enhancement, concentrating almost full terahertz energy on the waveguide’s surface when they are resonant with the terahertz waves and tunable resonant frequency. These abilities make the subwavelength waveguide coupling with the composite antennas be able to sever as a good integrated device to identify terahertz-sensitive small objects, or an excellent platform to terahertz spectroscopy and quantum research.

Deformation analysis and experiments for functional surface of composite antenna structure

Composite structure with embedded microstrip antenna array is a multifunctional structure that can provide the capabilities of a panel skin structure and a radar antenna simultaneously, and it is usually installed in the structural surface of the air, water, and ground vehicles. The environmental load under in-service conditions leads to structural deformations of the composite antenna structure. In this paper, theoretical analysis and experimental validations were presented to investigate the deformations of the functional surface in the composite antenna structure. An electromechanical coupling analysis method was proposed to evaluate the performance of the deformed composite antenna structure subjected to external loads. Composite antenna structure specimens were designed, fabricated, and measured. Using the specimens, experimental systems were built to investigate the deformation. The results show that structural deformation decreases the electromagnetic performance of the composite antenna. The coupling analysis method can be applied to evaluate the performance of the deformed composite antenna structure at the design stage.

J1010301 多目的タグチメソッドによる複合材アンテナシェル構造のロバスト設計

J1010301 多目的タグチメソッドによる複合材アンテナシェル構造のロバスト設計

Experimental Study of Composite-Antenna-Structures with High Electrical and Mechanical Performances

Embedding of an antenna within a structural surface is an excellent way to improve structural efficiency and antenna performance. We study the impact characteristics of a Composite-Antenna-Structure (CAS) and the degradation in the performance of the antenna after impact testing. We used an annular ring patch antenna designed to operate in two bands: GPS (1.575GHz) and DMB (2.62GHz). When 20J of impact energy was applied to the CAS surface, the maximum contact force was 4kN, and the CAS proved resistant to impact. The antenna performance, measured by the return loss and radiation pattern, remained excellent after the impact tests.

Composite-Antenna-Structure for Broadband Frequency

We study a composite-antenna-structure (CAS) having high electrical and mechanical performances that we have designed and fabricated. The CAS, consisting of a glass/epoxy face sheet and a honeycomb core, acts as a basic mechanical structure, in which a spiral antenna type is embedded. To increase the intensity, a carbon fiber plate is used as a bottom sheet. This structure of the 0.5 ~ 2 GHz band has a gain of 5 ~ 9 dBi with circular polarization characteristics and reflection loss below -10 dB within the desired frequency band.

Impact evaluation of composite-antenna-structure with embedded dual-band annular ring patch antenna

In this study, a composite-antenna-structure (CAS) for a dual band of global positioning system (1.575 GHz) and digital multimedia broadcasting (2.63–2.655 GHz) was designed and fabricated as a part of a structural skin. The annular ring antenna type is available in two frequency bands, depending on the critical point view at the feeding and resonant areas. Consequently, the CAS was investigated by impact tests because the efficiency of using a protective layer needed to be confirmed. Embedding an antenna within a structural surface is an excellent way to improve both mechanical efficiency and electrical performance. The measured results not only show the impact characteristics at critical points of this CAS but also the degradation in its electrical performance after the impact test. The experimental results indicated that impact tolerance was significantly increased by the use of composite laminates. The radiation pattern strongly depended on whether composite laminates protected the antenna elements. When 20 J of impact energy was applied to the CAS surface, the specimen with the composite laminates gave twice as much contact force. The antenna performance, as measured by the return loss and radiation pattern, remained excellent after the impact tests. These electrical performance results suggest that antennas with composite laminates will function properly despite local damage.

Design and fabrication of a composite-antenna-structure for broadband frequency with microwave absorber

Here we design, fabricate, and study a composite-antenna-structure (CAS) with excellent electrical and mechanical properties. The CAS, consisting of a glass/epoxy face sheet and a honeycomb core, acts as a basic mechanical structure in which a spiral type antenna is embedded. To increase the signal intensity, a carbon fiber plate is used as the bottom sheet. This reflector interrupts radiation, causing the wave from the antenna source to flow to the end of the arms without sufficient radiation. To overcome this problem, a microwave absorber is used for unwanted radiation to reduce the effect of the reflector. We measured the antenna performance by the return loss, axial ratio, gain, and radiation pattern. The structure showed a bandwidth of 0.5–2 GHz and a gain of 5–9 dBi, with circular polarization characteristics and a reflection loss below −10 dB within the desired frequency band.

Composite Patch Array Antenna with Built-In Polarizer and Its Road Clutter Reduction Effect for 76 GHz Automotive Radars

A composite patch array antenna with built-in polarizer has been developed to reduce road clutter noise by 20 dB for 76 GHz automotive radars. A polarizer is placed in front of Tx and Rx patch arrays within their reactive near-field region to suppress cross-polarized sidelobe radiation from their feeding lines while maintaining a low-profile characteristic with 4 mm thickness. Additional metal-lined absorbers within the composite antenna structure, while terminating cross-polarized waves undesirably excited by the patch arrays, also serve as miniature clutter plates to further reduce sidelobes toward the road surface. The resultant composite antenna achieved sidelobe levels of ―45 dB, a 20 dB improvement over standard patch arrays, at elevation angles close to 90°.