• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.1
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• pp.31-38
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• 2020

In this paper, we propose a quadruple band antenna for GPS/WLAN/WiMAX application. The proposed antenna has quadruple band characteristics by considering the interconnection of four strip lines and DGS on the ground place. The total substrate size is 20.0 mm (W1) ⨯27.0 mm (L1), thickness (h) 1.0 mm, and the dielectric constant is 4.4, which is made of 20.0 mm (W2)⨯ 27.0 mm (L8 + L6+ L10) antenna size on the FR-4 substrate. From the fabrication and measurement results, bandwidths of 60 MHz (1.525 to 1.585 GHz) bandwidth for GPS band, 825 MHz (3.31 to 4.135 GHz) bandwidth for WiMAX band and 480 MHz (2.395 to 2.975 GHz) and 385 MHz (5.10 to 5.485 GHz) bandwidth for WLAN band were obtained on the basis of -10 dB. Also, gain and radiation pattern characteristics are measured and shown in the frequency of triple band as required.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.7
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• pp.834-838
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• 2007

A coupled-defected ground structure(C-DGS) having closely-located DGS cells is proposed for high performance bandstop filter applications. The negative coupling of ground currents between adjacent DGS cells greatly improves the stopband characteristics. We have measured the attenuation slope of 110.8 dB/GHz and -20 dB rejection band from 3.8 GHz to 15.5 GHz. Compared to the double-plane BSF, the proposed BSF improved the sharp cutoff response 7.6 times. We expect the C-DGS be helpful to improve the performance of DGS application circuits and also to extend the possible DGS applications.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.7
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• pp.608-616
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• 2009

This paper presents a broadband CPS-fed Yagi-Uda antenna. The antenna has a feedline structure much simpler than other Yagi-Uda antennas and it provides more design flexibility in arranging the reflector. To improve the impedance matching, a tapered CPS line is inserted between the thick and thin feedlines. The proposed antenna exhibits the bandwidth of $3.9{\sim}5.9$ GHz (|G| < -10 dB) and the gain of $6.5{\sim}8$ dBi within that bandwidth. At the center frequency of 4.9 GHz, the antenna shows the gain of 7.4 dBi, and HPBW of $98^{\circ}$ along the x-z plane and $73^{\circ}$ along the x-y plane.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.9
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• pp.956-963
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• 2002

A linearly polarized folded type and H-shape slit folded type microstrip patch antenna at GPS(center frequency:1.575 GHz) were designed and fabricated by folding a conventional single $\lambda_{g}/2(\lambda_{g}:wavelength)$ rectangular patch a half along the length direction at the center of patch and inserting ground plane in the middle. As a result, two types of omnidirectional radiation patterns for E-plane (for zx-plane) in the direction of the length of patch and H-plane (for xy-plane) have been acquired. The experimental results show that the average gains of folded type and slit folded type for omnidirectional E-plane and H-plane are -1.5 dBd (-2.4 dBd) and -3.27 dBd(-2.5 dBd). Slit folded type microstrip patch antenna was more miniaturized than folded type microstrip patch antenna by 27.5 %. In case of slit folded type antenna, average gains of omnidirectional radiation pattern for E & H-plane are almost same.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.9
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• pp.924-931
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• 2002

In this paper, a new λ/4 bias transmission line that is added dumbbell-shaped defected ground structure(DGS) on ground plane of the conventional λ/4 bias transmission line is proposed. This DGS λ/4 bias transmission line maintains high characteristic impedance, but physical width is wider and length is shorter than that of the conventional bias line. If the proposed bias line is attached on signal transmission line, this bias line can reduces the $3^{rd}$ harmonic signal as well as the$2^{nd}$ harmonic signal. With harmonic reduction characteristics, efficiency and linearity of amplifier are improved. The proposed bias line is adopted in power amplifier on IMT-2000 base-station transmitting band. This paper presents several simulations and experimental results of DGS to show validity of the proposed power amplifier using the new λ/4 bias transmission line. Experimental results represent that the $3^{rd}$ harmonic signal is reduced about 26.5 dB and efficiency is improved about 9.1 % and IMD3 is improved 4.5 dB than the conventional structure.

• Journal of Advanced Navigation Technology
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• v.12 no.5
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• pp.420-428
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• 2008

In this paper, Stack structure patch antenna has been designed and fabricated for wireless LAN applications. The patch and ground plane were used by PEC metal. It was 0.05 [mm] thick. In order to broaden the bandwidth of the antenna and improve of gain, the stack structured antenna with probe feed. The measured input return loss showed less than -10 [dB] at the broadband from 5100 to 6140 [MHz]. It's measured bandwidth was 1040 MHz. The gain of antenna in the E-plane and H-plane was 13 dBi and 3 dB beam width was $40^{\circ}$.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.3
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• pp.10-14
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• 2017

A reverberation chamber is widely used in mobile handset measurements due to its faster and simpler measurement process compared to traditional anechoic chambers. We propose an ultra-wideband inverse conical antenna design suitable as a reference antenna in a reverberation chamber. Traditionally, multiple discone antennas are needed to cover more than 10:1 operation bandwidth of a reverberation chamber. The proposed inverse conical antenna offers wideband impedance matching bandwidth by virtue of the linear impedance transition along its oblique side. The antenna is feasible to mount on the conductive walls which can be utilized as a ground to improve the matching bandwidth, antenna gain and radiation patterns. The antenna geometry is optimized using a 3D electromagnetic simulation tool and fabricated using a 3D printer. The measured results show that the antenna reflection coefficient lower than -10dB and radiation efficiency more than 70% at the frequency range of 0.65~7 GHz.

• Journal of Advanced Navigation Technology
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• v.16 no.5
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• pp.766-772
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• 2012

In the present study, wideband microstrip monopole slot antennas which can be applied to the RF4CE Zigbee remote controller are designed. First I-shaped monopole slot antenna which has ${\lambda}g/4$ length at 2.45GHz is designed. In particular, a conducting via is used to connect the microstrip feed line and the ground plane surrounded with the etched slot for the bandwidth improvement. In order to reduce the antenna size, it is changed into L-shaped and T-shaped monopole slot antennas for which improve results of antenna performance are observed. In case of T-shaped monopole slot antenna, impedance bandwidth(VSWR<2) is about 3.32GHz, and also its radiation efficiency and gain is more than 90% and 2.1dBi respectively at whole operating frequency range. In particular, all of proposed monopole slot antennas have the end-fire radiations which has a maximum radiation power toward direction of open ends of monopole slots.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.9A
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• pp.900-905
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• 2006

In this paper, PIFA antenna for $2.40{\sim}2.482GHz\;and\;5.75{\sim}5.85GHz$ is designed, fabricated, and measured. The prototype consist of hair-pin and short-pin. To obtain suitable bandwidth, the form layer is inserted between ground plane and substrate. Important parameters in the design are hair-pin length, width, position, air-gap height, and feed point position. From these parameters optimized, a PIFA antenna is fabricated and measured. The measured results of the antenna are obtained as follows results. The resonant frequency of the fabrication PIFA antenna is 2.37GHz and 5.86GHz bandwidth for approximately 90MHz with 350MHz(VSWR<2.0) and the gain is $1.91{\sim}4.37dBi$. H-plan and E-plan at 2.4GHz and 5.8GHz are shown as $52.83^{\circ},\;85.90^{\circ}\;and\;68.68^{\circ},\;52.143^{\circ}$ respectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.8
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• pp.855-862
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• 2003

This paper suggests the PIFA structure modified antenna in which short-circuit plate is located between planar element and ground plane, in order to solve the problem of narrow band of existing internal antenna, PIFA. It is also suggested that internal antenna has the perturbation in the patch to broaden the frequency bandwidth. It is possible that the antenna is installed into the mobile telephone with a low profile condition(h=0.015 λ) to use internally, and acquired desired bandwidth(5.2 %) through double resonance structure, remodeling the PIFA that is already well-known as an internal antenna. This paper investigated how characteristic is affected by the feeding point(Yf, Zf), short strip plate(Zs), short strip width(Ws), perturbation width(w), length(d), short plate height(h), dielectric($\varepsilon$$\_$r/) to be slim type antenna. It is compared with existing PIFA bandwidth, and is suggested pattern as the H.E plane. It is simulated using the Microwave Studio of the CST Inc. based on FIM(Finite Integration Method) method and analyzed antenna characteristic following the variation each parameters. The result proved the practical use of PIFA antenna by comparing the measured and simulated data of the antenna.