• Journal of Advanced Navigation Technology
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• v.19 no.6
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• pp.623-629
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• 2015

In the present study, a coplanar waveguide (CPW)-fed printed monopole antenna with an inverted n-shaped slot is newly proposed for dual band operations which cover bandwidths of CDMA (1.85~2.025 GHz) and WLAN (2.4~2.484 GHz) as well as implementation of omnidirectional radiation pattern. For enhancement of impedance bandwidth ($S11{\leq}10dB$) in 2.4 GHz WLAN frequency band, an inverted n-shaped slot instead of the previous n-shaped slot is etched on the printed radiating monopole. The proposed antenna is designed and fabricated on one side of FR4 substrate with dielectric constant of 4.4, thickness of 1.6 mm, and size of $50{\times}25mm^2$. It has been observed that the measured impedance bandwidths are 280 MHz (1.84~2.12 GHz) in frequency band of CDMA and 420 MHz (2.38~2.8 GHz) in WLAN frequency band respectively. It is noticeable that impedance bandwidth in 2.4 GHz frequency band of WLAN is enlarged to three times due to use of inverted L-shaped slot in comparison with impedance bandwidth 140 MHz (2.39~2.53 GHz) obtained by use of the previous n-shaped slot. In addition, good omnidirectional radiation patterns have been observed over the entire frequency band of interest.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.9 s.100
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• pp.949-956
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• 2005

In this paper, a new CPW-fed cross shape fractal antenna having a self-affinity is presented. This novel configuration, which has anisotropic scaling symmetry, makes smaller profile characteristic compared to the fractal antenna using a self-similarity. Increase of the iteration coefficient, which leads to decrease of the fundamental resonant frequency, shows a good impedance matching condition and multi-band characteristics due to new surface current paths. The radiation patterns are similar to those of monopole antennas. In the K3 stage of iteration, the proposed antenna shows a measured maximum gain 2.27 dBi at 940 MHz. A commercially available software based on the FDTD algorithm has been used to obtain the predicted results. In addition, an RT/Duroid 5880 substrate has been employed for the experimental results.

• Journal of Advanced Navigation Technology
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• v.16 no.5
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• pp.773-780
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• 2012

ZOR(zeroth order resonance) antenna for 2.45GHz WLAN(wireless local area network) is designed by use of CRLH-TL(composite right left handed transmission line) meta-material. The electrical length of conventional antennas is determined generally according to the resonant frequency, whereas that of ZOR antenna can be determined without reference to the resonant frequency. Therefore ZOR antenna has advantage in miniaturization of antenna in comparison with conventional antennas. In order to design such ZOR antenna, first unit cell with electrical length shorter than a quarter wavelength at 2.45GHz is designed to the some characteristics of homogeneous medium. In order to decrease resonant frequency and enhance frequency bandwidth, the proposed antenna is fed by CPW(co-planar waveguide) and short stub between radiation patch and ground plane is used for obtaining both higher inductance and smaller capacitance than previous mush-room type of CRLH-TL.

• Journal of Advanced Navigation Technology
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• v.16 no.1
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• pp.27-34
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• 2012

In this paper, Coplanar waveguide(CPW)-fed slot loop antenna, which is applicable to the dual band(2.4GHz~2.4835GHz, 5.15GHz~5.825GHz) for the wireless LAN, is proposed. In order to miniaturize the proposed antenna, slot loop is bent by meandering. The resonant frequencies in the required dual band are adjusted by variation of the resonant length of slot loop as well as slot width. In particular, use of capacitive coupling CPW feed provides impedance matching without a seperate matching circuit, because the amount of electromagnetic coupling can be controlled by the offset between feed and radiator. As a result, it has been observed that the proposed antenna satisfies not only the required return loss(${\leq}10dB$) but also has high efficiency(${\geq}80%$) over the whole frequency band. In order to check the validity of the proposed antenna, some simulated results for return loss and radiation pattern are presented in comparison with the measured results.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.9
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• pp.60-66
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• 2008

In this paper, the CPW-fed Ultra-wideband antenna is designed and fabricated for UWB communications. To achieve ultra-wide bandwidth of the antenna, we propose the mutual coupling of two planar monopole antennas. The mutual coupling of monopole pair of the proposed antenna is optimized by adjusting the parameters, the widths of the planar monopoles and the space between two monopoles. Two UWB antennas with different horizontal sections of the CPW-fed monopole antenna are fabricated and measured to examine the mutual coupling effects on the monopole pair antenna. The measured result show that two antennas are satisfied with UWB communication band(3.1$\sim$10.6Ghz).

• Journal of IKEEE
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• v.17 no.2
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• pp.140-144
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• 2013

This paper presents the novel design of circular polarized Ka-band horn array antenna. The element antenna of the arrya is composed of two parts, microstrip patch and square horn, and the microstrip patch is fed by corner truncated microstrip patch for circular polarization. The patch antenna has the role of a feeder and polarizer of the horn, thus the whole size of the horn antennae can be considerably reduced. The $1{\times}8$ horn array was designed and fabricated by the spacing of $0.9{\lambda}_0$ among the element horn. The element horn has typical gain of 8dBi and axial-ratio bandwidth of 4.9% at 3dB, and the minimum gain and axial-ratio bandwithd of the array is 14dBi and 8.2%.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.5
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• pp.759-766
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• 2022

In this paper, we propose a multi-band small antenna with CPW(Coplanar Waveguide) feeding structure WLAN(Wireless Local Area Network) and WiMAX (Worldwide Interoperability for Microwave Access) bands. The proposed antenna is designed two slit in the modified monopole type radiator and FR-4 substrate, which is thickness 1.0 mm, and the dielectric constant is 4.4. The size of proposed antenna is 15.1 mm⨯16.41 mm, and total size of proposed antenna is 17.5 mm⨯16.4 mm. From the fabrication and measurement results, From the fabrication and measurement results, bandwidths of 439 MHz (2.06 to 2.499 GHz), 840 MHz (3.31 to 4.25) and 1,315 MHz (5.23 to 6.545 GHz) were obtained on the basis of -10 dB impedance bandwidth. Also, 3D radiation pattern characteristics of the proposed antenna are displayed and measured gains 2.24 dBi, 2.83 dBi, and 2.0 dBi shown in the three frequency band, respectively.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.7
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• pp.3140-3145
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• 2012

In this paper, a design method for a compact slot antenna fed by a coplanar waveguide (CPW) is studied. A T-shaped tuning stub is inserted inside a narrow rectangular slot and the slot is impedance matched to the CPW feedline by adjusting the width, length, and position of the stub. The resonance frequency is adjustable by the slot length and the antenna size can be reduced by bending the slot. The resonance frequency and impedance matching property of the compact slot antenna are similar to those of the half-wavelength slot antenna, which enables one to design compact antenna of this type with ease. A compact slot antenna for 2.45-GHz ISM band is designed, fabricated on an FR4 substrate (dielectric constant of 4.4 and thickness of 0.8 mm), and experimentally tested. The measured results agree well with the simulations, which confirms the validity of this study. The fabricated compact slot antenna shows an impedance bandwidth of 200 MHz(2.32-2.52 GHz) for a VSWR < 2, which is suitable for 2.45-GHz ISM band (2.4-2.48 GHz). The measured radiation patterns show ${\infty}$-shaped directional pattern in the E-plane and nearly omni-directional pattern in the H-plane with a peak gain of 2.0 dBi, which are similar to those of a monopole antenna. The proposed antenna is expected to be suitable for the applications as antennas for WLAN, RFID, and mobile handset.

• Journal of the Korea Institute of Military Science and Technology
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• v.23 no.5
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• pp.459-465
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• 2020

In this paper, a compact antenna assembly for an amplitude comparison direction-finding(DF) method for a small flight vehicle is presented. Designed antenna assembly consists of four antennas and it is mounted on a radius of 1.45 λ_c where λ_c corresponds to the wavelength of the center frequency. To achieve compactness and robustness of the assembly, the elements are fed by end-launch feeding method and have modified aperture shapes of E- or H-sectoral horns. The feeding part consists of SMA connector, stepped impedance matching structure, and square waveguide of 0.6 λ_c × 0.6 λ_c. To achieve different main beam directions for every antenna which is required condition for amplitude comparison DF method, all apertures of the antennas are inclined and it makes the main beam direction of each antenna to top, bottom, left, and right with respect to the axis of the platform. To verify the validation of DF performance of the presented antenna assembly, amplitude comparison curves using measurement results are presented. The bandwidth of the antennas are above 3.2 % in Ku-band(VSWR ≤ 2:1).

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.1
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• pp.119-123
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• 2005

In this paper. It is proposed and fabricated that the new antenna of dual T type structure is shifted easily center frequency. This antenna consists of dual dipoles resemblance to dual T type, which are fed by a coplanar waveguide (CPW) on signal plane. The analyzed and measured characteristic of new antenna is controled between distance of two dipoles for shifting center frequency. The proposed antenna is 450MHz bandwidth for using IMT2000 band. The characteristic parameters of the proposed antenna are analyzed by using a FDTD methods.