• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.3 s.94
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• pp.235-245
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• 2005

In this paper, a novel Ultra-Wideband(UWB) antenna fed by CPW is designed, fabricated, and measured for UWB communications. We have used the Microwave Studio of CST to simulate the proposed antenna. It is designed to work on a substrate TMM4 of thickness 0.762 mm and relative permittivity 4.5. The proposed antenna is satisfied with Ultra-Wideband communication band from 3.1 GHz to 11.5 GHz, for VSWR$\leq$2, and isolated IEEE 802.1la frequency band(5.15 GHz$\~$5.825 GHz) using a rectangular slot. Measured group delay variation is less than 1 ns, thus indicating the proposed antenna a good candidate for UWB applications.

• 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.941-948
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• 2005

In this paper, we have proposed a Ultra-Wideband slot notch antenna by using a semi-circular extension. The proposed antenna cover the entire UWB band(3.1${\~}$10.6 GHz) and notch out the IEEE 802.1la frequency band(5.15${\~}$5.825 GHz) by inserting a $\lambda$/4 length slot into the patch. A prototype antenna was fabricated on FR-4( ${\epsilon}_r$ =4.4, substrate thickness=0.8 mm) and measured for VSWR characteristics. The measured notched frequency variations versus frequency for different slot length. The path loss and group delay were measured. The proposed antenna also show a good gain flatness(1.9 dBi) except the IEEE 802.1la frequency band.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.5 s.108
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• pp.416-422
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• 2006

In this paper, we have designed and favricated the high gain and wideband microstrip patch antenna including IEEE 802.11a. To widen the bandwidth of microstrip antenna, firstly we have used the microstrip line-coaxial probe feeding method and inserted a U-slot in the rectangular patch. Secondly, to improve the antenna gain, we have used a $2{\times}2$ array structure. From the measured results, wideband characteristics of 1 GHz bandwidth($5.110{\sim}6.142$ GHz) for VSWR<2 was obtained. The measured eain was 13 dBi in both the E-plane and H-plane at the frequency of 5.15 GHz, 5.35 GHz, 5.50 GHz, and 5.85 GHz.

• 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.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.1
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• pp.215-220
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• 2016

In this paper, a wideband antenna accomplished by adding a double sleeve of a rectangular planar monopole structure is proposed. In order to impedance matching of proposed antenna, the antenna performance was improved by adding two gap sleeves and outer sleeve for double sleeve structure. HFSS simulator of ANSYS corp. was used in order to confirm the antenna parameter characteristic. According to the simulation results, the VSWR was less than 2 for the range of 2.5GHz~10.5GHz. The frequency bandwidth is 8GHz. The frequency range of the actual fabricated antenna was 2.92GHz~10.32GHz, the frequency bandwidth is 7.4GHz. The measured radiation pattern frequency is 3GHz, 6GHz and 9GHz. The results are similar with dipole antenna pattern in all frequency. The antenna size is $40{\times}40mm^2$. The utilization possibility of the ultra-wideband planar monopole antenna could be confirmed according to compare and analyze the simulation and measurement data.

• Proceedings of the IEEK Conference
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• 2000.09a
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• pp.91-94
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• 2000

In this paper, the performance of the W-CDMA system with smart antenna is investigated. The realistic wideband channel is assumed, one of which is JTC(Joint Technique Committee) channel model. It is also assumed that multipaths are clustered. The beamforming-RAKE receiver structure of W-CDMA system is proposed, whose performance is analyzed on the assumption of perfect channel estimation. The probability density function (pdf) of SINR(Signal to Interference and Noise Ratio) for different number of antennas and users is presented, and the BER(Bit Error Rate) is presented based on that. As a result, the performance of the W-CDMA system with smart antenna in the realistic wideband channel has been considerably improved.

• Journal of electromagnetic engineering and science
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• v.13 no.1
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• pp.22-27
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• 2013

This paper describes a wideband double dipole quasi-Yagi antenna fed by a microstrip-to-slotline transition. The transition feed consists of a microstrip radial stub and a slot radial stub, each with the same angle of $90^{\circ}$ but with different radii, to achieve wideband impedance matching. Double dipoles with different lengths are utilized as primary radiation elements to enhance bandwidth and achieve stable radiation patterns. The proposed antenna has a measured bandwidth of 3.34~8.72 GHz for a -10 dB reflection coefficient and a flat gain of $6.9{\pm}0.6$ dBi across the bandwidth.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.12
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• pp.573-577
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• 2002

We designed wideband HTS antennas which consists of two triangle -radiation patches using a $YBa_2Cu_3O_{7-X}$ (YBCO) superconducting thin film. The major limitation of high-Tc superconducting (HTS) microstrip antennas is the narrow bandwidth due to the high Q and thin substrate. Defining bandwidth as the frequency range over which standing wave ratio (SWR) 2:1 or less, HTS antenna bandwidths are typically 0.85 % to 1.1 %. Thus considerable effort has been focused on developing antennas for broadband operation. To calculate input impedance and design of the broadband HTS antennas a moment method technique was used. The HTS antenna fabricated in this work was designed for K-band, which is useful band for satellite to satellite communications. The bandwidth obtained was a significant 6.7 % and the other measured performance of our HTS antenna, including the bandwidth, radiation Pattern, efficiency, standing wave ratio (SWR) and return losses was reported.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.523-526
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• 2002

We designed wideband HTS antennas which consists of two triangle-radiation patches using a YBa$_2$Cu$_3$O$\sub$7-x/ (YBCO) superconducting thin film. The major limitation of high-Tc superconducting (HTS) microstrip antennas is the narrow bandwidth due to the high Q and thin substrate. Defining bandwidth as the frequency range over which standing wave ratio (SWR) 2:1 or less, HTS antenna bandwidths are typically 0.85% to 1.1%. Thus considerable effort has been focused on developing antennas for broadband operation. To calculate input impedance and design of the broadband HTS antennas a moment method technique was used. The HTS antenna fabricated in this work was designed for K-band, which is useful band for satellite-to-satellite communications. The bandwidth obtained was a significant 6.7% and the other measured performance of our HTS antenna, including the bandwidth, radiation Pattern, efficiency, standing wave ratio (SWR) and return losses was reported.

• Journal of the Korea Institute of Military Science and Technology
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• v.7 no.4 s.19
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• pp.20-25
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• 2004

The existing antenna that equipped with Micro Aerial Vehicle, microstrip antenna only can send and receive image signal because of limited bandwidth. But, proposed antenna that equipped with Micro Aerial Vehicle flight introduces tapered type patch antenna, also improves bandwidth then can transfer present location, altitude, movement speed. Furthermore, as a result of introduce stacked type, it transfers more quality of image signal, and represents most suitable performance in Korean peninsula that has many mountain peaks. In this paper, to transmit and receive the wideband signals with a antenna system, the wideband microstrip antenna is proposed and designed. This antenna operates at 2.4GHz. In this thesis, the resonance frequency of 2.4GHz and the reflective loss of the antenna of -22dB were calculated by measuring the fabricated Tapered Microstrip Patch Antenna which was designed with the resonance of 2.4GHz. The calculated gain and efficiency of antenna were 6.7dB and $60\%$ respectively. The characteristic of the bandwidth shows with $50\~60MHz$ which is $6.02\%$ at the basis of -l5dB reflective loss. The experimental results can be used in the characteristic of the resonators and this antenna produces a greatly enhanced bandwidth.