Small antennas

Fujimoto, K.; Morishita, Hisashi

doi:10.1017/cbo9780511977602.003

Cited by 33 publications

(52 citation statements)

References 2 publications

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“…Formally, an antenna is classed as electrically small if the product of the wavenumber, k (= 2π/λ), and the radius of an imaginary sphere circumscribing the maximum dimension of the antenna, a, is less than or equal to 0.5; note that the parameter ka is unit-less [2][3][4]. It is widely accepted that as the electrical size of an antenna is reduced, its performance (in terms of gain, efficiency, and bandwidth) deteriorates.…”

Section: Introductionmentioning

confidence: 99%

“…Generally, the radiation resistance decreases, while the reactive component of its impedance increases, leading to a poor match with the feed line or network. As such, there is a compromise between miniaturization and performance; small antenna theory dictates that a favourable compromise is reached when the antenna fully occupies a volume defined by the radius a [2][3][4][5][6][7][8]. Consequently, there is tremendous potential in the successful manufacture of novel, 3D antenna geometries -hitherto too complex to fabricate with traditional processes -using emergent technologies such as holographic photolithography, 3D printing, direct-write printing, direct transfer patterning, thermal transfer printing, and aerosol jet printing [9][10][11][12][13][14][15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

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Selective Electron Beam Melting Manufacturing of Electrically Small Antennas

Mufti¹,

Smith²,

Tennant³

et al. 2017

Adv. sci. technol. eng. syst. j.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Selective Electron Beam Melting Manufacturing of Electrically Small Antennas

Mufti¹,

Smith²,

Tennant³

et al. 2017

Adv. sci. technol. eng. syst. j.

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“…As a consequence of UWB technology, the design of low cost antennas with omni-directional radiation patterns, large bandwidth and non-dispersive behaviour is quite crucial and challenging concept in wireless and personal communication systems (Schantz, 2005;Fujimoto et al, 1987). In addition, these antennas should utilize full UWB bandwidth (3.1-10.6 GHz) and be small in size for portable wireless applications.…”

Section: Introductionmentioning

confidence: 99%

Modified Hilbert fractal geometry, multi‐service, miniaturized patch antenna for UWB wireless communication

Kaka

Toycan

Bashiry

et al. 2012

COMPEL - The International Journal for Computation and Mathematics in Electrical and Electronic Engineering

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Purpose -The purpose of this paper is to describe a modified Hilbert-based fractal antenna for ultra wideband (UWB) wireless applications. Simulation results show excellent multi-band characteristics for UWB wireless applications. Design/methodology/approach -A Hilbert curve-based fractal is optimised for self-replicating, space-filling and self-avoiding properties. In the proposed design, the Hilbert curve is applied to a rectangle as an initial iteration and maintained for the later iterations. Additionally, a Yagi-like strip is removed from the second iteration of the Hilbert patch and a hexagonal portion is removed from the substrate to achieve good optimization. The antenna feed is created through a micro-strip line with a feeding section. Finally, a partial ground plane technique is used for improved impedance matching characteristics. A finite element method (FEM) is used to simulate the modified Hilbert model with commercially available Ansoft HFSS software. Findings -The proposed antenna is miniaturized (39 mm length £ 30 mm width) and has multi-band characteristics. The simulation results show that the antenna has a reflection coefficient characteristic of ,210 dB, a linear phase reflection coefficient, better than 65 percent radiation efficiency, 2.2-4 dBi antenna gain and nearly omni-directional radiation pattern properties over the UWB bandwidth (3.1-10.6 GHz). Originality/value -The antenna shows promising characteristics for the full 7.5 GHz UWB bandwidth. In addition, the performance is achieved by using laceration techniques on the Hilbert patch and substrate, respectively. A partial ground plane ensures impedance matching of 50 over full UWB bandwidth. The simulation analysis of the modified Hilbert fractal antenna design constitutes the main contribution of the paper.

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“…A lot of research findings for antennas have been reported by using peculiar materials such as ferrite substrate, by using slow-wave structure, and by using loading reactance elements [1], [2], [3].…”

Section: Introductionmentioning

confidence: 99%

Integrated Slot Spiral Antenna Etched on Heavily-High Permittivity Piece

Takigawa

Kashihara

Kuroki

2007

2007 Asia-Pacific Microwave Conference

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Radiation characteristics of printed slot antennas etched on a high permittivity piece with a relative dielectric constant of 197 were investigated for the purpose of miniaturization of antennas. At first, the effect of shortening of the wavelength caused by use of the high permittivity dielectric material was calculated from the viewpoint of the return loss performance, and it was obvious that the wavelength was reduced by about 37 % using slot antenna etched on a high permittivity piece with a relative dielectric constant of 197. Two types of slot antennas with double and single twin spiral configurations were fabricated by using the high permittivity piece of 10 mm square on a side with a thickness of 2 mm. Each return loss was measured to be larger than 10 dB.

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Small antennas

Cited by 33 publications

References 2 publications

Selective Electron Beam Melting Manufacturing of Electrically Small Antennas

Selective Electron Beam Melting Manufacturing of Electrically Small Antennas

Modified Hilbert fractal geometry, multi‐service, miniaturized patch antenna for UWB wireless communication

Integrated Slot Spiral Antenna Etched on Heavily-High Permittivity Piece

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