• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.5
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• pp.445-450
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• 2002

We analyzed and measured a CPW(coplanar waveguide)-to-microstrip right-angled transition. Asymmetric CPW-to-microstrip transitions show significant resonances by the slot mode generation at the discontinuities. The air-bridge just shifting the resonance frequency can not fundamentally suppress the occurrence of the slot mode. So, we proposed the structure using offset microstrip section to eliminate the resonance. The proposed structure may be useful for the application of multi-layed structure.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• pp.116-120
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• 2004

In this paper, we proposed a method to shift the resonant frequency by applying the electric field to microstrip patch antenna using piezoelectric substrates. We fabricated microstrip patch antenna using Y-cut LiNbO3, Quartz and FR-4 substrates. We designed and simulated the microstrip antennas by Ensemble V 7.0 of the simulation too1. We observed the resonant frequency by DC applied electric field in a microstrip patch antenna. When the electric field was 300 V/mm, the resonant frequency agile of Y-cut LiNbO3 microstrip patch antennas were 29 MHz. When the electric field was 400 V/mm, the frequency agile of X-cut, Y-cut and Z-cut quartz microstrip patch antennas were 55.2 MHz, 34.2 MHz and 28.0 MHz, respectively. However, when the electric field was 400 V/mm, the resonant frequency of FR-4 microstrip patch antenna does not changed. It was shown that the resonant frequency agile of Y-cut and Z-cut quartz microstrip patch antennas are due to piezoelectric phenomenon not to be permittivity.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• pp.224-225
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• 2005

The microstrip patch antenna with PVDF (poly vinylidene fluoride) substrate, were experimentally studied at frequency 6 GHz. During the design of the essential elements of microstrip antenna, EM simulation tool Ensemble V 7.0 is used. We observed the resonant frequency by DC appled electric field in a microstrip patch antenna. This research has been made as an electronically tunable microstrip antenna, taking advantage of the voltage control dielectric substrate and piezoelectric properties substrate. We discuss the effect of substrates, electric field and piezoelectric phenomena in the PVDF microstrip antenna. The antenna frequency can be changed by varying the applied dc voltage. In this paper, we propose, a new technique to agile frequency of the microstrip antenna by using the PVDF piezoelectric substrate.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.5
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• pp.169-175
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• 2006

In this paper, a microstrip patch antenna with the T-shaped slits is designed and fabricated for GPS. The resonant frequency of the microstrip patch antenna with the slits is lower than that of a microstrip patch antenna without the slits so it can be reduced the size of patch. In order to calculate resonant frequency of the microstrip patch antenna with the slits, the resonant frequency formulas are derived from the surface current distribution on microstrip patch antenna. Using the Ensemble 6.0 simulation tool, the accuracy of approximate equations is verified. The microstrip patch antenna with the slits is designed by using these equations. The size of the designed antenna with T-shaped slits can be reduced to 29% compared with that without the slits. The microstrip patch antenna with slits have a very narrow bandwidth. In order to improve the narrow bandwidth of microstrip patch antennas with the slits, a microstrip patch antenna with rectangular slot is proposed. As the result of the measurements, the resonant frequency of the proposed microstrip patch antenna with the T-shaped slits is 1.575GHz and the bandwidth is about 50MHz.

• Proceedings of the IEEK Conference
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• pp.163-166
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• 2000

The design, numerical simulation, and an experimental implementation of two-element cross-shaped microstrip line-fed printed slot array antenna for IMT-2000 at the 2.0 GHz band is presented in this paper. The proposed antenna with relative permittivity 4.3 and thickness 1.0mm is analyzed by the Finite-Difference Time-Domain (FDTD) method. It was shown that the measured 2.0 VSWR bandwidth of one-element microstrip slot antenna is from 1.42 GHz to 2.69 GHz, which is approximately 61.8% and that of two-element microstrip slot array antenna is from 1.42 GHz to 2.56 GHz, which is approximately 57.3% And it was shown that the measured gain of one-element microstrip slot antenna is 2.75 dBi and that of two-element microstrip slot antenna is 4.75 dEi. The antennas were fabricated and tested. The measured results are in good agreements with the FDTD results.

• 제어로봇시스템학회:학술대회논문집
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• pp.1664-1667
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• 2003

Aperture-coupled microstrip antenna is one type of microstrip antennas. This type of antenna has bandwidth wider than simple microstrip antenna. Herein, we use two substrates, that have the same dielectric constant 2.47 (PTFE-quartz) in which upper substrate is a rectangular patch. The microstrip patch is fed by a microstrip line which is printed on lower substrate, through an aperture or slot in the common ground plane of patch and microstrip feed. This antenna is analyzed by using Finite Difference Time Domain (FDTD) method the specific design frequency 10 GHz and match impedance is 50 ohms. The simulation results of its characteristics are input impedance, return loss, VSWR and radiation patterns respectively.

• Proceedings of the KIEE Conference
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• pp.1946-1949
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• 2002

본 논문에서는 밀리미터파 대역에서 저손실 특성이 우수한 전송선로인 non-radiative dielectric (NRD) guide와 microstrip의 transition에 관해 연구하였다. 본 연구에서 이용된 transition은 aperture coupling을 이용한 것으로 NRD와 microstrip 사이의 aperture를 통하여 magnetic field가 coupling되는 원리이다. Aperture의 구조를 각각 rectangular와 ridge 형태로 설계하였다. 비교를 위해서 설계된 microstrip to microstrip transition의 경우 aperture의 구조를 ridge 형태로 했을 때 rectangular 일 때 보다 삽입손실 특성이 개선되었고 더 넓은 bandwidth를 가지는 것을 알 수 있었다 NRD to microstrip transition의 경우는 bandwidth 면에서 ridge 구조와 rectangular 구조 모두 비슷한 특성을 보였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• pp.63-64
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• 2015

In this paper, a microstrip array antenna capacitively coupled to a microstrip line is studied. The array antenna consists of uniformly spaced rectangular microstrip patches arranged close to a feeding microstrip line on a grounded dielectric substrate. The effects of various parameters, such as strip width and length, distance between adjacent patches, gap between strip patches and microstrip feed line, on the antenna performance were examined. By properly adjusting geometrical parameters, the array suitable for a high gain antenna for use in a frequency band centered at 12.5 GHz was designed.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.1081-1085
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• 2015

In this paper a printed pair dipole antenna with double tapered microstrip balun for wireless communications is proposed. The proposed antenna consists of a pair arm of different sizes that is branched microstrip line and microstrip line with the ground plane on opposite side of the dielectric substrate plane. The proposed antenna is matched between the ground plane to the microstrip line by double tapered microstrip balun. This antenna obtains multi-band radiation frequency band. The impedance bandwidths for a reflection coefficient of VSWR ≤ 2 are about 1.01 GHz (2.35~3.336 GHz), 1.56 GHz (4.7~6.26 GHz) and 1.15GHz (6.85~8.0[GHz]). Additionally, the measurement peak gain is about 3.6 dBi. The proposed antenna is able to support wireless communication applications.

• Journal of Information Technology Services
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• v.12 no.3
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• pp.323-330
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• 2013

In this paper, miniaturized patch antenna operating at ISM band has been designed by applying the fractal technique. Various type of antenna structure, microstrip patch antenna and koch curve microstrip patch antenna has been proposed and simulated using Ansoft HFSS (High Frequency Structure Simulator). The area of microstrip patch antenna and koch microstrip patch antenna is 1,058 $mm^2$, and 891 $mm^2$ respectively, showing the size reduction ratio of 16%. The finally made koch curve microstrip patch antenna resonates at 2.45GHz with return loss of 22.69dB, VSWR of 1.2142, and antenna radiation gain of 3.26dBi.