• Journal of electromagnetic engineering and science
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• v.13 no.2
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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.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.16 no.5
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• pp.362-368
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• 2023

In this paper, we presented the characteristics of the impulse signal which is applicable to the ultra-wideband antennas. In general, the width of the impulse has around sub nano or pico seconds in the time domain, where it corresponds to the wideband in the frequency domain. We confirmed by experiment that the impulse has around 130ps of the pulse width and bandwidth of 4GHz when 10MHz of sine wave excited as an input pulse. The fidelity factor was calculated in the time domain and -10dB bandwidth in the frequency domain was investigated for resistively loaded dipole antennas with different resistance per unit length. The received impulse signal through the wideband antennas is confirmed in the time and frequency domains that received pulse is to be similar to the generated impulse. The fidelity and bandwidth of the quantity value are 0.98 and 3.4GHz, respectively.

• ETRI Journal
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• v.31 no.1
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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 Electrical Engineering and Technology
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• v.13 no.1
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• pp.400-405
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• 2018

This paper presents a compact ultra-wideband (UWB) flexible monopole antenna design on a paper substrate. The proposed antenna is made of iterations of a circular slot inside an octagonal metallic patch. This fractal-based geometry has been deployed to achieve compactness along with improved bandwidth, measured reflection coefficient -10 dB bandwidth ranging from 2.7 to 15.8 GHz. The overall size of the antenna is $26mm{\times}19mm{\times}0.5mm$, which makes it a compact one. The substrate used is paper and the main features like environment friendly, flexibility, green electronics applications and low cost of fabrication are the key factors for the proposed antenna. The aforementioned UWB prototype is suitable for many wireless communication systems such as WiMAX, WiFi, RFID and WSN applications. Antenna has been tested for the effect of bending by placing it over a curved surface of a very small radius of 10 mm.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.12
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• pp.30-36
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• 2009

Various types of ultra-wideband components with 10's of GHz bandwidth have been developed utilizing a uniplanar ultra-wideband balun, which is a simple microstrip-to-coplanar stripline (CPS) transition structure with the operating frequency range from near DC to over 40 GHz. Developed ultra-wideband components include antennas, mixers, doublers, and detectors in a carrier type and in a surface mountable type. One of surface mountable components, for example, single balanced doubler has output frequency 8 ~ 28 GHz. These high-Performance, low-cost ultra-wideband components may replace expensive conventional components, and also can be used to develop new multi-GHz OWE application areas.

• Journal of Communications and Networks
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• v.5 no.4
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• pp.328-343
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• 2003

Orthogonal pulse-shape modulation using Hermite pulses for ultra-wideband communications is reviewed. Closedform expressions of cross-correlations among Hermite pulses and their corresponding transmit and receive waveforms are provided. These show that the pulses lose orthogonality at the receiver in the presence of differentiating antennas. Using these expressions, an algebraic model is established based on the projections of distorted receive waveforms onto the orthonormal basis given by the set of normalized orthogonal Hermite pulses. Using this new matrix model, a number of pulse-shape modulation schemes are analyzed and a novel orthogonal design is proposed. In the proposed orthogonal design, transmit waveforms are constructed as combinations of elementary Hermites with weighting coefficients derived by employing the Gram-Schmidt (QR) factorization of the differentiating distortion model’s matrix. The design ensures orthogonality of the vectors at the output of the receiver bank of correlators, without requiring compensation for the distortion introduced by the antennas. In addition, a new set of elementary Hermite Pulses is proposed which further enhances the performance of the new design while enabling a simplified hardware implementation.

• ETRI Journal
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• v.36 no.3
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• pp.460-468
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• 2014

This paper addresses the problem of joint time of arrival (TOA) and direction of arrival (DOA) estimation in impulse radio ultra-wideband systems with a two-antenna receiver and links the joint estimation of TOA and DOA to the sparse representation framework. Exploiting this link, an orthogonal matching pursuit algorithm is used for TOA estimation in the two antennas, and then the DOA parameters are estimated via the difference in the TOAs between the two antennas. The proposed algorithm can work well with a single measurement vector and can pair TOA and DOA parameters. Furthermore, it has better parameter-estimation performance than traditional propagator methods, such as, estimation of signal parameters via rotational invariance techniques algorithms matrix pencil algorithms, and other new joint-estimation schemes, with one single snapshot. The simulation results verify the usefulness of the proposed algorithm.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2005.11a
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• pp.205-210
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• 2005

In this paper, a planar half-circle shape ultra-wideband(UWB) antenna fed by CPW is designed, fabricated and measured for UWB communications. Within the UWB band(3.1 GHz $\sim$ 10.6 GHz), 5.15 GHz $\sim$ 5.825 GHz frequency band is used by IEEE 802.lla WLAN applications. It may be necessary to notch out this band to avoid interference with IEEE 802.lla WLAN. Therefore, we have proposed three kinds of UWB antennas having a notch function, such as a rectangular slot, a hat-shaped slot, a circle-shaped slot. The notch frequency of the proposed antenna can be adjusted by controlling the slot length or slot width. From the measured results, the proposed antennas show a good gain flatness except the IEEE 802.lla WLAN frequency band and have a reasonable agreement with simulated results.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.8
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• pp.913-919
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• 2008

A new design and its experimental results of a microstrip-fed ultra-wideband tapered slot antenna(TSA) for millimeter-wave systems are presented. By utilizing the ultra-wideband microstrip-to-CPS transition(balun), ultra-wideband characteristics of the inherent TSA are retrieved. Also, the design procedure of the TSA is simplified by performing simple impedance matching between balun and antenna. The proposed TSA is shaped by using the Fermi-Dirac tapering function and corrugated at the outer edge. The implemented antenna demonstrates ultra-wideband performance for frequency ranges from 23 to over 58 GHz with the relatively high and flat antenna gain of 12 to 14 dBi and low sidelobe levels. In addition, a 4-element linear antenna array for phased-array systems and mm-wave sensor applications is also presented.

• ETRI Journal
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• v.32 no.1
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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.