다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

In general, Micropower Impulse Radar (MIR) depends on Ultra-Wideband (UWB) transmission systems. UWB technology can supply innovative new systems and products that have an obvious value for radar and communications uses. Important applications include bridge-deck inspection systems, ground penetrating radar, mine detection, and precise distance resolution for such things as liquid level measurement. Most of these UWB inspection and measurement methods have some unique qualities, which need to be pursued. Therefore, in considering changes to Part 15 the FCC needs to take into account the unique features of UWB technology. MIR is applicable to two general types of UWB systems: radar systems and communications systems. Currently LLNL and its licensees are focusing on radar or radar type systems. LLNL is evaluating MIR for specialized communication systems. MIR is a relatively low power technology. Therefore, MIR systems seem to have a low potential for causing harmful interference to other users of the spectrum since the transmitted signal is spread over a wide bandwidth, which results in a relatively low spectral power density.

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Response to FCC 98-208 notice of inquiry in the matter of revision of part 15 of the commission's rules regarding ultra-wideband transmission systems

소형 안테나 ( Small Antennas )

The fifth generation (5G) mobile networks are envisaged to enable a plethora of breakthrough advancements in wireless technologies, providing support of a diverse set of services over a single platform. While the deployment of 5G systems is scaling up globally, it is time to look ahead for beyond 5G systems. This is mainly driven by the emerging societal trends, calling for fully automated systems and intelligent services supported by extended reality and haptics communications. To accommodate the stringent requirements of their prospective applications, which are data-driven and defined by extremely low-latency, ultra-reliable, fast and seamless wireless connectivity, research initiatives are currently focusing on a progressive roadmap towards the sixth generation (6G) networks, which are expected to bring transformative changes to this premise. In this article, we shed light on some of the major enabling technologies for 6G, which are expected to revolutionize the fundamental architectures of cellular networks and provide multiple homogeneous artificial intelligence-empowered services, including distributed communications, control, computing, sensing, and energy, from its core to its end nodes. In particular, the present paper aims to answer several 6G framework related questions: What are the driving forces for the development of 6G? How will the enabling technologies of 6G differ from those in 5G? What kind of applications and interactions will they support which would not be supported by 5G? We address these questions by presenting a comprehensive study of the 6G vision and outlining seven of its disruptive technologies, i.e., mmWave communications, terahertz communications, optical wireless communications, programmable metasurfaces, drone-based communications, backscatter communications and tactile internet, as well as their potential applications. Then, by leveraging the state-of-the-art literature surveyed for each technology, we discuss the associated requirements, key challenges, and open research problems. These discussions are thereafter used to open up the horizon for future research directions.

A Prospective Look: Key Enabling Technologies, Applications and Open Research Topics in 6G Networks

This review aims to cover experimental data on oxidative effects of low-intensity radiofrequency radiation (RFR) in living cells. Analysis of the currently available peer-reviewed scientific litera...

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Oxidative mechanisms of biological activity of low-intensity radiofrequency radiation

In this paper, bandwidth reconfigurable bandstop filter using uni-planar electromagnetic bandgap (EBG) structure is proposed. Bandstop filter is fabricated by loading microstrip transmission line with periodic uni-planar EBG structure. The loaded EBG cells are not connected to each other, with and without connecting EBG cells the bandwidth of the stop band is varied. The PIN diodes are used to connect and disconnect the EBG cells. The measured 10-dB bandwidth of the stop band in the on state is from 6.41 GHz to 7.33 GHz and in the off state is from 6.84 GHz to 7.47 GHz, 290 MHz change in bandwidth is achieved.

Bandwidth reconfigurable bandstop filter using planar EBG structure

This paper presents a compact planar 3.5 GHz/5.5 GHz dual-band multiple input multiple output (MIMO) USB dongle antenna for WiMAX applications. Each antenna element has rectangular patch radiator fed by microstrip line bend. For miniaturization of antenna elements a U-shaped slot is cut in the ground plane of each antenna element with one end open and other end short. The proposed MIMO antenna has two similar elements and for improving coupling a tapered inverted T-shaped slot is cut in between the antenna elements at the ground plane side. The MIMO antenna has achieved coupling less than −20.2 dB in lower band (3.45-3.59 GHz) and less than −21.5 dB in upper band (5.46-5.58 GHz). The measured and simulated results show good agreement in both the bands. Moreover, the proposed design is also tested for its gain, efficiency, and envelope correlation coefficient at 3.5 GHz and 5.5 GHz, which shows that the proposed dual-band MIMO USB dongle antenna is suitable for WiMAX applications.

Compact Planar 3.5/5.5 GHz Dual Band MIMO USB Dongle Antenna for WiMAX Applications

A multilayer bandpass filter (BPF) with harmonic suppression using meander line inductor and interdigital capacitor (MLI-IDC) resonant structure is presented in this letter. The BPF is fabricated with three unit cells and its measured passband center frequency is 2.56 GHz with a bandwidth of 0.38 GHz and an insertion loss of 1.5 dB. The harmonics are suppressed up to 11 GHz. A diplexer using the proposed BPF is also presented. The proposed diplexer consists of 4.32 mm sized unit cells to couple 2.5 GHz signal into port 2, and 3.65 mm sized unit cells to couple 3.7 GHz signal into port 3. The notch circuit is placed on the output lines of the diplexer to improve isolation. The proposed diplexer has demonstrated insertion loss of 1.35 dB with 0.45 GHz bandwidth in port 2 and 1.73 dB insertion loss with 0.44 GHz bandwidth in port 3. The isolation is better than 18 dB in the first passband with 38 dB maximum isolation at 2.5 GHz. The isolation in the second passband is better than 26 dB with 45 dB maximum isolation at 3.7 GHz.

A Harmonic Suppressed Bandpass Filter and its Application in Diplexer

A novel UWB (ultra wideband) BALUN/180° Power Divider utilizing the broadband characteristics of microstrip — slotline transition is reported. The measured operational frequency range of the BALUN on RO4003C substrate is 4GHz–45GHz, corresponding to a typical insertion loss of 4±1dB with an amplitude and phase imbalance of under ±1dB and ±7° respectively. Simulation and measurement of the design on LTCC substrates show reduced loss of around 3.5±1dB with amplitude and phase imbalance of under ±1dB and ±4° respectively, in addition to an increased operational frequency range of 8GHz–90GHz, and reduction in the physical dimensions to 3 mm × 8 mm. Simulations and initial measurement with sapphire substrate have shown the capability of the design to hold good up to 130 GHz.

Ultra wide band balun/180° power divider using microstrip-slotline-microstrip transition

In this paper, frequency selective surface (FSS) properties of a uniplanar electromagnetic band-gap (EBG) unit cell are used to improve the gain and aperture efficiency of a probe feed microstrip patch antenna. The unit cell shows the pass band characteristics at 7 GHz. An array of $9\times 9$ unit cell is used of dimension $38.88\times 38.88\ \mathbf{mm}^{2}$ to achieve gain improvement of 2.57 dB and aperture efficiency of 77.79%-86%.

Mahesh P. Abegaonkar

Papers

Bandwidth reconfigurable bandstop filter using planar EBG structure

Compact Planar 3.5/5.5 GHz Dual Band MIMO USB Dongle Antenna for WiMAX Applications

A Harmonic Suppressed Bandpass Filter and its Application in Diplexer

Ultra wide band balun/180° power divider using microstrip-slotline-microstrip transition

Gain and Aperture Efficiency Improvement using Uniplanar EBG Superstrate