Science Daily January 31, 2019 Researchers in Japan developed algorithm for computer simulation of electric circuits in which transmission lines are connected with lumped element models. They introduced the incidence matrix found in circuit theory and time domain impedance to connect partial differential equations and ordinary differential equations which are used to solve transmission line problems. Based on the results of calculations using this algorithm, the researchers demonstrated that EM noise could be reduced by using the symmetric 3-line configuration of the circuit. Their calculation method is for one-dimensional multi-conductor transmission lines, but they have already developed a calculation algorithm […]
Category Archives: Communications technology
Manhole Covers Serve as Antennas Expanding Wireless Network Coverage
IEEE Spectrum December 18, 2018 High-speed bandwidth, and the use of the millimeter wave spectrum needed for 5G networks barely propagate around the corners of buildings. To overcome this issue, the strategy has been a combination of small cells with massive MIMO antennas to increase coverage. To manage to get all these small cells dispersed throughout a city landscape, researchers in the UK propose using manhole covers as antennas for mobile communications. It eliminates traffic disruptions from street construction, and there are no antennas awkwardly placed on buildings, marring the appearance of a neighborhood. The manhole does not interfere with […]
Laser-pointing system could help tiny satellites transmit data to Earth
Phys.org December 14, 2018 CubeSats struggle to efficiently transmit large amounts of data down to Earth due to power and size constraints. To fine-point its downlink beam, researchers at MIT utilize an uplink beacon signal captured by an on-board detector and tracked by an off-the-shelf MEMS fast steering mirror. As these miniature actuators lack feedback sensors, the system design is augmented with an optical calibration signal to provide the mirror’s pointing feedback. They developed calibration algorithms utilizing the feedback signal to achieve higher fidelity beam pointing control. Experimental results show that beacon tracking errors of only 16 μrad root-mean-square are feasible […]
China is racing ahead in 5G. Here’s what that means.
MIT Technology Review December 18, 2018 In its 13th Five-Year Plan the government describes 5G as a “strategic emerging industry” and “new area of growth,” and in its Made in China 2025 plan, which outlines its goal of becoming a global manufacturing leader, it vows to “make breakthroughs in fifth-generation mobile communication. To make this happen the Chinese government is committed to giving Chinese operators large chunks of spectrum for 5G. Unlike in the US, Chinese carriers will mostly use a spectrum band similar to what they used for 3G and 4G. Under government direction, Chinese companies began conducting research […]
Companies fed up with crappy Wi-Fi are deploying 5G instead
MIT Technology Review November 28, 2018 5G is expected to popularize private cellular networks because it was designed with more capabilities, slash data transmission delays from about 30 milliseconds to less than one and it can be programmed to treat different types of data or equipment differently— favoring mission-critical devices so that they keep operating even if the rest of the network is disrupted. Automakers, oil companies, and shipping ports plan to build private 5G networks for faster, more reliable connectivity. Companies need networking equipment, software, and—most important—access to spectrum…read more.
World’s first single-panel antenna to simultaneously support multiple 5G communications
Phys.org November 29, 2018 Researchers in Japan have developed technology which delivers high-speed communications in excess of 10 Gbps, as required by 5G mobile communication formats. By controlling the phase of signals separately emitted from 128 antenna elements with high accuracy they have suppressed the interference between signals. This enables simultaneous communications in four directions using only one antenna panel. Signals can be varied in both horizontal and vertical directions expanding the communications area. With these developments, components can now be fit on a single 13 cm2 printed circuit board enabling the deployment of compact base stations and high-speed 5G […]
An important step towards completely secure quantum communication network
Phys.org November 28, 2018 For practical long-distance quantum communication room-temperature atomic vapours are important. Atomic motion has so far limited the single-excitation lifetime in such systems to the microsecond range. Researchers in Denmark have demonstrated that lifespan of the quantum state at room temperature can be extended to about a quarter of a millisecond. They used a small glass container, filled with Cesium atoms, in which they were able to load, store and retrieve single photons from, the quantum states necessary for the repeater. This technique improves the life span of the quantum states at room temperature a hundred times…read […]
New Spot-Beam Antennas Boost Communication Satellites’ Bandwidth
IEEE Spectrum September 28, 2018 A company based in the US has built massive communications satellites. The spot beams produced by antennas onboard focus in slightly different directions, allowing the same spectrum bands to be used multiple times without interference. Spot beams ultimately function similarly to cell towers. Eventually, the 18V and 19V will look down on Earth with their spot beams and wide beams. The 18V and 19V use the Ku (12 to 18 gigahertz) and Ka (26 to 40 GHz) bands for their spot beams and wide beams…read more.
Russian scientists have increased the Internet speed up to one and a half times
Eurekalert August 31, 2018 Researchers at the University of Missouri have developed an algorithm based on a special routing method which provides quick access to the most powerful large data processing centers in the world. The quality and speed of data transmission is achieved due to the superior constrained shortest path finder algorithm made by the scientists. Thus, the data transmission speed can be increased up to 50%. This is relevant for solving problems that require high-precision calculations both in the field of fundamental science and for the implementation of applied projects. According to the scientists, to use this algorithm, […]
Quantum dot floating gates improve light-erasable memories
Physics World August 3, 2018 Researchers in South Korea have significantly improved the performance of photoresponsive flash memories made from OFETs by making use of floating gates based on cadmium selenide quantum dots whose surfaces have been modified. They found that modifying the surfaces of the dots affected the performance of the memories and found that capping small ligands of octadecylphosphonic and fluorinated molecules improved the diffusion of holes between the dots and the conducting channels in the devices. The new devices have memory ratios of over 105 between OFF and ON bi-stable current states for over 10,000 seconds and […]