• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.12
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• pp.1706-1711
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• 2013

This paper presents the filter of a resonator comprising a shorted open gap ring(SOGR) and interdigital lines. The proposed filter has the ultra wideband characteristic operating from 3 GHz to 10.5 GHz. In order to achieve the remarkable improvement in the size-reduction of the overall filter structure, only one cell of the SOGR with the inter-digital lines is adopted. It is shown that this filter has the size of $18mm{\times}15mm$ using a metamaterial, the fractional bandwidth over 100%, the insertion loss much less than 1dB, an acceptable return loss performance in the results.

• Journal of the Semiconductor & Display Technology
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• v.9 no.2
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• pp.7-10
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• 2010

In this paper, we design a modem SoC (System on Chip) for low power consumption and high speed wireless communications. Among various schemes of high speed communications, an MB-OFDM (Multi Band-Orthogonal Frequency Division Multiplexing) UWB (Ultra-Wide-Band) chip is designed. The MB-OFDM uses wide-band frequency to provide high speed data rate. Additionally, the system imposes no interference to other services. The 90nm CMOS (Complementary Metal-Oxide Semiconductor) technology is used for the SoC design. Especially, power management mode is implemented to reduce the power consumption.

• Journal of Communications and Networks
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• v.5 no.4
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• pp.386-393
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• 2003

Future wireless networks are expected to achieve high bit rates at low cost, enabling multimedia and QoS-based services over the wireless medium. The impulse radio ultra-wide band (IR-UWB) technique is a promising candidate in the deployment of such networks, thanks to its potential robustness and capacity. In the past, most of the UWB research focused on hardware and physical layer aspects in order to solve the technological challenges posed by IR-UWB. UWB peculiar characteristics may, however, also stimulate innovative higher layers’ design. This work addresses MAC issues for UWB communication systems. Key areas such as medium sharing, MAC organization, packet scheduling and power control are reviewed. The impact of UWB on the above functions is discussed, and areas which require UWB specific design are identified. Finally, novel MAC functions enabled by UWB specific features, i.e., precise ranging and positioning, are presented.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.1C
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• pp.102-108
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• 2006

In this paper, we propose an interference cancellation(IC) scheme using a partial Rake(PRAKE) combining in ultra-wideband(UWB) multipath fading channels. In this IC scheme, differently from the conventional transmitter model, which employs a guard interval between each frame, the guard interval is employed between each slot for estimating the multiple access interference(MAI). The UWB systems using the proposed IC scheme have little performance degradation without regard to the number of user, while the conventional UWB systems have a significant performance degradation according to the number of user. In order to reduce the receiver complexity, the PRAKE combining of post-canceled signal and the partial user IC scheme are also proposed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.30 no.3
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• pp.236-242
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• 2019

Ultra-wideband(UWB) is a technology that can transmit and receive signals at high speeds using a very short signal of wideband of several GHz, and has been recently used in the field of radar technology. Impulse radio(IR)-UWB radar is used in the field of motion recognition with high resolution. In this work, we studied motion recognition using IR-UWB radar. We constructed a development environment to acquire data about motion and implemented a signal processing algorithm for performance enhancement. Based on the signal processing result, the performance was verified through feature extraction and learning of motion.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.12C
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• pp.1623-1632
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• 2004

In this paper, we analyze the performance of linear search and bit reversal search algorithms based on the single-dwell serial search for rapid UWB (Ultra Wide Band) signal acquisition in typical indoor wireless channel environments. Simulation results according to bin spacing and frame interval in IEEE 802.15 Task Group 3a UWB indoor wireless channels show that bit reversal search algorithm achieves much smaller normalized mean acquisition time than linear search algorithm. In particular, it is found that the normalized mean acquisition time of the bit reversal search according to the range of searching termination interval closely matches the ideal case. In addition, we observe that the acquisition performance of bit reversal search algorithm becomes much better as bin spacing gets finer.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.1
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• pp.69-76
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• 2015

In this paper, we propose and analyze a M-ary transmission scheme in time hopping ultra-wide band(UWB) system using mutually orthogonal modified Hermite polynomial(MHP) pulses. The proposed M-ary transmission scheme employs the orthogonal property between different ordered pulses and N data bits make the M-ary signals by linear combination of M MHP pluses. The theoretical analysis and simulation results show that the proposed system has better performance and higher data rate than conventional M-ary UWB system. We derive the general form of correlation function for MHP pulses and analyze bit error rate(BER) performance over additive white Gaussian noise(AWGN) with the presence of timing jitter. We show that the proposed system has the improved BER performance and robustness to timing jitter and low power spectrum density compared with conventional M-ary UWB system.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.465-468
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• 2014

In this paper, we describe a method capable of measuring biological signals including respiration, heart rate, blood pressure, and blood sugar, using UWB (Ultra Wide Band) pulses, while does not contact the human body. Physiological signal is a basic data for checking the health. Because life is longer and active area of human becomes very broad, the medical system and the physical human resources which are focused on existing hospital must be located close patient, In that way, they hope be to engage in healthy life by stepping a quick step and treatment. Thus, it must be fitted closely to the patient. It is necessary to monitor the health without inconvenience on an ongoing basis. How to utilize radio waves in this way have been studied for a long time. However, the characteristics of radio waves on the human body has not been accurately grasped and developed as such. Accordingly, it is a level that can not be applied clinically. So, it is not widely put to practical use. In this paper, We analyzed and described the impact and characteristics of UWB pulses to the human body is a problem existing.

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1649-1651
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• 2002

Ultra-wide bandwidth (UWB) detection method has been widely used as a front end detection scheme for the ultra-high frequency (UHF) partial discharge (PD) monitoring systems. A broad-band video detector module was developed and characterized for the UHF UWB PD detection systems. The useable bandwidth of the module is more than 2 GHz and it is optimized for 50-ohm systems. The detection sensitivity and dynamic range of the module were characterized by using a known ns-width RF pulses of GHz range. The dynamic range is more than 6-decades and the module can detect pulsed RF signals down to 1 nW. The detector module can eliminate expensive equipment such as high speed oscilloscopes and radio frequency (RF) spectrum analyzers. Therefore, it enables one to use slow speed data acquisition systems for the PD monitoring at the UHF range. The detector module was used to detect real PDs of about <3 pC. The module converts the UWB PD signals into a low-bandwidth video signal with a high signal-to-noise ratio.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.5
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• pp.815-820
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• 2008

Recently the frequency assignment and the technical specifications of UWB systems for communications are completed. Therefore many UWB systems have been developed. In our country $3.1{\sim}4.8GHz$ and $7.2{\sim}10.2GHz$ are assigned for UWB systems for communications. When we consider RF technologies and the easy implementation of UWB systems, UWB systems used in the low band are more developed than high band systems. In this paper we design and implement a BPF for low band UWB systems by means of considering the easy implementation of UWB systems. The designed and implemented BPFs are low band filter and low band channel filters. The measured results of the low band filter show that the filter has 21.85dB and 17.91dB attenuation at 3.1GHz and 4.8GHz, 1.53GHz of -10dB bandwidth and 2dB of insertion loss. Low band can be divided into 3 channels with 500MHz of the channel bandwidth. The channel filter for channel number 1 has the characteristics of 24.85dB attenuation at 3.1GHz, 0.61GHz of -10dB bandwidth and 1.87dB of insertion loss. The filter for channel 3 in low band has 19.2dB of attenuation at 4.8GHz, 0.49GHz of -10dB bandwidth and 2.49dB of insertion loss.