Jinyul Kim

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.

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.

Behavioral characteristics of composite-antenna-structure covering three bands under compression load

A composite-antenna-structure covering three bands of global positioning system (1.575 GHz), digital multimedia broadcasting (2.62 GHz) and direct broadcast satellite (11.7–13.5 GHz) was designed and fabricated as a part of the structure surfaces. A new concept of antennas integrated into a composite sandwich structure provides a design that is an electrically and structurally effective multi-functional antenna structure. We designed two types of antennas. One is an annular ring patch antenna for global positioning system and digital multimedia broadcasting. The other is a microstrip patch antenna for direct broadcast satellite. In the design process, the effects of the composites and adhesive films are considered for in the design processes, because structural materials affect the antenna performance. Additionally, the composite-antenna-structure was designed by considering the coupling effect in a strict substrate. The measured results of buckling tests have provided useful information regarding not only the compression behavioral characteristics but also its degradation in electrical performance before and after the test. The experimental results have shown good results for compressive tolerance, though the specimens after compression loading returns to their original shape before failure. Additionally, an acoustic emission system is implemented in the buckling test system to study the inner behavior of the composite-antenna-structure for the reliability of secure mechanical performance. The antenna performance, as measured by the return loss and radiation pattern, remained excellent after the compression tests. These electrical performance results suggest that antennas with composite laminates will function well despite damage.

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.

Investigation for impact behavior of composite surface antenna

We study the impact characteristic and the performance of composite surface antenna (CSA). The antenna, which operates in GPS band (1.575 GHz) and DMB band (2.635 GHz), was embedded in composite sandwich structure consisting of glass/epoxy laminate, carbon/epoxy laminate, adhesive films and nomex honeycomb. When 20 J of impact energy was applied to arbitrary points on the antenna, the maximum contact force was 4 kN and the antenna proved resistant to impact. The gain of antennas after impact testing was about 6 dBi in GPS band and 4.5 dBi in DBS band.