Papers by Keyword: Antenna

Abstract: This study explores the formulation of dielectric composite material derived from Ananas comosus (pineapple) waste for 5 GHz microstrip antenna applications. Cellulose extracted from pineapple leaves was incorporated into an epoxy matrix to achieve a permittivity (ε_r) of 4.13. Morphological analysis revealed cellulose fiber particles averaging 1.60 μm in diameter, embedded within a composite matrix rich in carbon and oxygen. EDX analysis confirmed composition percentages of 62.07 wt.% carbon, 33.95 wt.% oxygen, and 3.98 wt.% sodium. Antenna performance evaluation demonstrated an optimal reflection coefficient, S₁₁, of -32 dB at 5.30 GHz in simulations, meeting FCCs 5G band specifications. The three-dimensional radiation patterns from the simulations confirmed efficient power radiation, with a gain of 4.246 dBi, indicating the suitability of the dielectric composite for effective signal transmission and reception. Experimental results showed an S₁₁ of -22 dB at 5.15 GHz, validating robust performance within the 5 GHz range. These findings underscore the potential of pineapple waste-derived composites in advancing sustainable antenna technology.

Abstract: In this paper, a microstrip line-fed rectangular-shaped ultra-wideband (UWB) antenna offering triple-band notch characteristics is proposed. The notching was done primarily to provide rejection for Wi-Max (3.3-3.7 GHz), WLAN2 (5.15-5.825 GHz), and ITU (8.025-8.4 GHz) through the combination of slots and a modified electromagnetic band gap (M-EBG). The antenna was simulated using HFSS and CST modelling tools. The antenna was able to notch three frequencies from narrow band communication systems (Wi-Max, WLAN2, and ITU), causing interference within the UWB band. The gain of the system over the operating frequency, the current distributions, and the impedance covered were studied to assess the effectiveness of the antenna. The proposed antenna is simple and compact, with a total antenna size of 19 mm by 24 mm and a wide bandwidth (3.2 to 12.5 GHz). Satisfactory results have been obtained when its performance was analyzed. A stable radiation characteristic is observed with a radiation efficiency of 94% when operating at a UWB resonant frequency of 6.85 GHz with a total gain between -10 dB and 5 dB within the range of the frequency band of 3.2 to 12.3 GHz.

Abstract: This paper presents parametric study of dual band notch ultra wideband (UWB) antenna using modified electromagnetic band gap. The Electromagnetic Band Gap (EBG) comprises of two strip patched and an edge-located via with respect to ground for dual notch band. The study was presented in order to have an improved knowledge of EBG characteristics and its effect on the notching band of a small squared ultra wideband antenna of size 24 by 31 mm² dual band notch using HFSS software. The antenna operates within the return loss (s11< -10dB) 3.2 to 12.3 GHz. The simulation results show that the notched band between 4.57 – 4.99 GHz and 7.96 – 8.32 GHz corresponding to WLAN and ITU respectively was achieved. The effect of gap distance between the field line and EBG was demonstrated as well and the position of via with respect to the ground as a means for notched band centre frequency tuning. The antenna could be considered a good candidate for any UWB applications that must avoid narrow band interference. The research gives ideas on the best placement position of EBG structure along field line in UWB antenna frequency notching technique.

Abstract: This paper presents illustrative electromagnetic modelling and simulation of graphene antenna using a two-dimensional graphene sheet of zero thickness and a three-dimensional graphene slab of finite thickness. The properties of the antenna are analyzed in terms of the S11 parameter, input impedance, VSWR, radiation pattern, and frequency reconfiguration using the full-wave electromagnetic simulator. Furthermore, this work numerically studies the modelling of graphene antenna using a three-dimensional graphene thin slab and the impact of graphene slab thickness on the performance of graphene antenna.

Abstract: A design and simulation for L-shaped slot microstrip line antenna with semicircle defected ground structure has been researched, the main purpose is suppressing the existence of higher order harmonic. In this paper, simulated soft (Ansoft HFSS V.6.0) used to be simulated the frequency response under different parameters such as dimensions, amounts of SDGS. The results show good performance of SDGS in higher resonant frequency suppression. Final, an antenna with 2.4GHz center frequency had been design and fabricated.

Abstract: Abstract.In order to ensure higher accuracy and better electrical performance of large antennas in future,this paper does some research for deformation of antenna’s reflector:modeling for 25m antenna and reappearing deformation when elevation changes every 15° just considering gravity by using ANSYS.Using results of simulation obtains deformation error curves with elevation changes, creates the conditions for compensating distortion and has a certain value. By using Ruze formula, deeply studies the regular about antenna’s electrical performance influenced by deformation because of elevation changes,obtains meaningful data and tables of relationship between elevation and parameters of electrical performance in nine bands of 25m antenna.It finds out that when working in high-frequency band, efficiency and gain loss of antenna will be more affected by elevation angle changes.Finally creates conditions for optimizing antenna parameters and performing high reliability tasks such as deep space exploration and aerospace communication.

Abstract: In our work on micro-fabricated hair-sensors, inspired by the flow-sensitive sensors found on crickets, we have made great progress. Initially delivering mediocre performance compared to their natural counter parts they have evolved into capable sensors with thresholds roughly a factor of 30 larger than of their natural equivalents. Due to this disparity, and also instigated by our work on fly-halteres inspired rotation rate sensors and desert locust ear-drum mimicking membrane struc- tures, we have analysed the differences in performance between natural and man-made sensors. We conclude that two major drawbacks of main-stream micro-fabrication are the lack of easily applicable soft materials, as well as the limitations imposed by photolithography based fabrication with respect to freeform 3D shaping of structures. Currently we are targeting additive manufacturing for biomimetic sensor structures and in this contribution we report initial results of 3D printed sensor structures.

Abstract: In order to improve the stealth performance of antenna, a metamaterial absorber with high absorption, polarization-insensitive and wide angle based on the electromagnetic resonance is designed. Using of ultra-thin characteristic of absorber, they are attached to the microstrip antenna to reduce its radar cross section. The simulation results show that the new microstrip antenna’s radiation performance remains unchanged compared with conventional microstrip antenna and it has obvious RCS reduction in its working band. While the maximum reduction can reach 28dB at working frequency, and the in-band reduction of antenna is above 3dB. This indicates that the absorber can be used for antennas’ in-band stealth.

Abstract: The electromagnetic compatibility (EMC) of the whole system should be guaranteed to ensure the electronic and electrical equipments can work without interference from each other. The article introduces the scripting language of HFSS and details the architecture of automatic control technique for EMC. Finally, the antenna isolation analysis among 3 wire monopole antennas set on an oval carrier was taken as an example to demonstrate the calculation process.

Abstract: Ultra-wideband (UWB) technology was nowadays increased in interest for various applications due to its distinctive characteristics where it able to carry signals passes through obstacles unlikely narrow-band frequency that tends to reflect the signal. Through this paper, a design of miniaturized implantable UWB antenna utilizing various bio-compatible materials is studied. These materials are to be compared and determined the best material to be used for the design in terms of its return loss, center frequency, bandwidth, antenna gain and total efficiency. The antenna is designed in a structure of circular-ring with slit patch antenna using CPW profile with dimension of 10×10 mm². As for the materials used in this study are Silicon, PDMS and Teflon PTFE. Each of this substrate has a thickness of 0.5 mm, 2.5 mm, and 1.5 mm correspondingly. After comparing these three materials, the one that gives the best result is Teflon PTFE with return loss at 11.91 GHz and 5.58 GHz bandwidth that covers from 9.16 GHz to 17.74 GHz frequency range. The antenna gives out total gain and efficiency of 2.54 dB and 86.5% respectively.