• ETRI Journal
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• 제32권1호
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• pp.62-67
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• 2010

In this paper, an ultra-wideband internal antenna for use in mobile applications is proposed. The proposed antenna has symmetrical bi-arm structures printed on the top and bottom of the substrate, and it occupies a compact area of 10 mm ${\times}$ 10 mm ${\times}$ 1 mm. The designed antenna has an impedance bandwidth from 3 GHz to 12 GHz and near omnidirectional radiation patterns over the frequency band of interest. The group delay between two antennas fabricated using the proposed design is less than 0.8 ns, and the maximum gain variation is about 3.16 dB.

• 전기학회논문지P
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• 제58권1호
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• pp.33-37
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• 2009

In this paper, a printed small Ultra-Wideband (UWB) antenna with directive radiation characteristics based on combination of electric-magnetic radiators is presented. The combinations of the electric and magnetic type antennas result in the directive radiation patterns for all observed UWB frequency band. Simple combination of dipole antenna and loop antenna is also presented to show that proper configuration of electric radiator and magnetic radiator can produces directive radiation characteristics. The target frequency is from 3.1 GHz to 10.6 GHz with size of $15\;mm{\times}31\;mm$. A proto-type of the combined antenna is simulated, fabricated and measured. Simulation and experimental results of input impedance and gain characteristics of the proposed antenna are presented. There are good agreements between the simulated and measured VSWR curves. Also, the results show the directive radiation characteristics with small antenna form factor over the target frequency range.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제54권6호
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• pp.286-292
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• 2005

Terahertz wave is a kind of electromagnetic radiation whose frequency lies in 0.1THz $\~$10THz range. In this paper, generation and detection characteristics of terahertz (THz) radiation by photoconductive antenna (PCA) method has been described. Using modern integrated circuit techniques, micron-sized dipole antenna has been fabricated on a low-temperature grown GaAs (LT-GaAs) wafer. A mode-locked Ti:Sapphire femtosecond laser beam is guided and focused onto photoconductive antennas (emitter and detector) to generate and measure THz pulses. Ultra-wide band THz radiation with frequencies between 0.1 THz and 3 THz was observed. Terahertz field amplitude variation with antenna bias voltage, pump laser power, pump laser wavelength and probe laser power was investigated. As a primary application example. a live clover leaf was imaged with the terahertz radiation.

• 한국전자파학회논문지
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• 제27권7호
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• pp.653-659
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• 2016

본 논문은 공중에서 회전하면서 광대역 신호를 방향 탐지하고 수신하는 반사판 안테나 급전기용 초광대역 LPDA(Log-Periodic Dipole Array) 안테나를 제안한다. S 대역부터 Ka 대역까지 20:1 이상의 초광대역 특성을 확보하기 위해 평면기판 위에 방사소자를 인쇄하였고, 기판 사이에 견고한 구조의 쐐기형 유전체 지지대를 삽입하였다. 또한, 무게를 줄이기 위해 지지대 중심 부분을 스티로폼 재질로 대체하였다. 설계된 LPDA 안테나의 5-dB 반사손실 대역폭은 시뮬레이션 37.57:1(1.09~40.95 GHz), 측정 33.85:1(1.31~44.35 GHz)로 초광대역 특성을 나타내었다. 동작 대역에서 평균 이득은 시뮬레이션, 측정 각각 5.79 dBi, 5.76 dBi로서 요구하는 이득을 확보하였다. 제안된 견고하고 가벼운 초광대역 LPDA 안테나는 항공용으로 적용될 수 있음을 확인하였다.

• ETRI Journal
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• 제27권4호
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• pp.453-456
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• 2005

The ultra-wideband (UWB) signal radiation process in an antenna is different from that of a narrowband signal. In this paper, we study the degradation of the desired signal component according to the antenna structure and location of a receiver in a bipolar time-hopping UWB system. And we propose a receiver structure with an adaptive template waveform generator to compensate for the degradation caused by a realistic TX-RX antenna system.

• Journal of electromagnetic engineering and science
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• 제13권1호
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• pp.34-37
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• 2013

This paper presents a novel ultra-wideband (UWB) antenna that rejects narrow and broad bands and is suitable for wireless communications. The base of the proposed antenna has a circular patch that can cover the UWB frequency range (3.1~10.6 GHz). The interference issues caused by co-existence within the UWB operation frequency are overcome by a design that uses a parallel-coupled asymmetric dual-line with a circular monopole antenna. The proposed antenna showed a stable radiation pattern, realized gain and reflection coefficient lower than -10 dB across the UWB operation bandwidth except for 5.15~5.85 GHz and 7.25~8.4 GHz. The fabrication, simulation, and measurement results obtained for the proposed antenna were in good agreement with the expected values.

• ETRI Journal
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• 제31권1호
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• pp.71-73
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• 2009

In this letter, novel antennas with two spiral elements are presented for ultra-wideband application. The original antenna consists of a T-shaped microstrip feed line, two spiral radiating elements, and a ground plane with two circular slots. It measures 30 mm ${\times}$ 40 mm ${\times}$ 1.6 mm. Spiral elements are used to increase the lower bandwidth limit. To further reduce the size of the antenna, the original antenna is cut in half by using the symmetry of the surface current distributions. The proposed antennas feature omnidirectional radiation patterns and good gain flatness.

• Journal of electromagnetic engineering and science
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• 제13권2호
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• pp.63-72
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• 2013

The ultra-wideband (UWB) spectrum available for commercial applications has offered us an opportunity to achieve high-speed wireless communications and high-accuracy location applications. As one of key research areas in UWB technology, a lot of innovative broadband and miniaturization techniques for UWB antennas have been greatly invented and developed for years. This paper reviews the development of UWB antenna design in the past decade. Starting with a brief introduction of the specific requirements and promising applications of UWB systems, the unique design challenges of UWB antennas are highlighted. Next, the important milestones of UWB antenna designs are briefed. After that, a variety of planar UWB antennas invented for broadband operation, miniaturization, and multiple functions are introduced. Last, the comments on the development of UWB antennas in future are shared.

• Journal of electromagnetic engineering and science
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• 제14권1호
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• pp.31-35
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• 2014

An ultra-wideband (UWB) circular monopole antenna with a multiband-notched characteristic is proposed. The multiband-notched filter consists of three different sized folded slots, which are distinctly assigned for the notched band at the 3.5-GHz WiMAX, 5-GHz WLAN, and 8-GHz ITU bands. The proposed antenna results in a measured ${\mid}S_{11}{\mid}$ < -10 dB, which completely covers the UWB band (3.1 10.6 GHz) with three notched bands at 3.5, 5.5, and 8.0 GHz. The antenna yields an omnidirectional radiation pattern and high radiation efficiency.

• 한국정보통신학회논문지
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• 제21권9호
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• pp.1642-1648
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• 2017

초광대역 안테나는 위성통신, 레이더, 리모트 센싱 시스템, 전파 망원경, 마이크로웨이브 화상 시스템 등의 여러가지 용도로 쓰인다. 수많은 형태의 광대역 안테나 구조들이 있으나, 테이퍼 슬롯 비발디 안테나는 가격, 무게, 스캔각도, 종형 복사, 쉬운 급전과 시스템 구성의 용이성 등의 장점이 있다. 이 논문에서는 개선된 안티포달 비발디 안테나를 제안하였다. 설계에 있어서 H자 형태의 기생패치 구조를 채택하였으며 이를 통해 전체 작동 주파수에 있어서 방사특성을 개선하는 능력을 나타내었다. 비유전율(${\epsilon}_r$) 2.2, 유전체 두께 0.7874mm의 RT/duroid 5880기판을 사용해 제안된 안테나의 시작품을 제작하고 측정한 결과 7.8-52.5GHz에 걸쳐 -10dB 반사손실 대역폭과 9-12dBi의 이득을 보였으며 이는 시뮬레이션 결과와 합리적으로 일치함을 확인하였다.