The bandwidth of a computer network is a measure of the rate of data transfer.  Limits on bandwidth may result from physical limitations of the media as well as processing limitations.  Increasing b...
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Cloud computing is an emerging model for the delivery and consumption of information technology (IT) resources. Infrastructure-as-a-service cloud providers deliver virtual servers along with network c...
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The most salient feature of wireless communication channels is signal propagation over multiple scattering paths. Although this so-called multipath signal propagation leads to undesirable signal fadin...
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Computer networks function by connecting spatially separated computers with “links” – electrical conductors, fiber optics and radio waves.  The majority of network protocols work by dividing a ...
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In a phased-array antenna the relative phases of the signals feeding the antennas are varied in such a way that the effective radiation pattern is reinforced in a desired direction and suppressed in u...
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In radiofrequency (RF) communications systems such as wireless local area networks (LANs) and 3G and 4G mobile networks, multiple input, multiple output (MIMO) technology has been crucial for achievin...
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The rapid proliferation of wireless devices has caused a surge in data rates. Higher frequencies including millimeter wave frequencies (30-300 GHz) are being explored to address the spectrum crunch.At...
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The demand for smaller wireless communication devices that use less power is growing. In particular, radio frequency identification (RFID) systems require small, low-power transmitters to label or “...
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In a multiple-input, multiple-output (MIMO) system, multiple antennas are used at both the transmitter and receiver to improve communication performance. MIMO systems are key to high capacity communic...
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Wideband high-dimensional antenna arrays are expected to play a key role in future wireless systems. Due to narrow bandwidths, phased array/beamforming methods are the natural choice when it comes to ...
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High frequency (HF), very high frequency (VHF) and ultrahigh frequency (UHF) bands have long been used for many different communication systems, particularly in military applications. Standard monopol...
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Quantum cascade lasers (QCLs) are semiconductor lasers that provide light in the mid- and far-infrared wavelength ranges. They are designed so that the generated light is transverse-magnetic (TM) pola...
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A traveling wave tube (TWT) is a vacuum electronic device that acts as a microwave amplifier capable of providing high gain and high output power. TWTs are used in many wireless devices like radar sys...
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Monopole antennas are a type of radio antenna consisting of a straight, rod-shaped conductor often mounted perpendicularly over a conductive surface (a ‘ground plane’) such as the earth. This type...
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In contrast to random access memory (RAM), content addressable memories (CAMs) allow data to be located simply by knowing the desired data value. CAM memory receives the desired value and then returns...
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Many data-intensive networked systems rely on high-performance indexes that link pairs of ‘keys’ with storage addresses. These indexes help locate and process large volumes (i.e., terabytes) of da...
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To execute a computer program, a processor can access memory to read or write data. The accessed data may be identified by a unique physical address. Modern systems are able to hide the physical addre...
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Networks allow data exchange between linked computers. Data messages are divided into packets, which are able to navigate complex and changing networks. A router, or switch, reads packet addresses and...
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Wireless sensing technology provides an unprecedented ability to monitor the physical environment by using a network of cheap sensor nodes. Current approaches to extracting information from a wireless...
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In wireless telecommunications, signals are transmitted and received over transmission channels within a limited range of frequencies, typically between 0.7 GHz to 6 GHz for domestic applications. Due...
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Ultrawideband technologies, including certain wireless communication and radar operations, receive and transmit information across a broad swath of radio frequencies by radiating narrow pulses of info...
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Microtubes are minute structures of layered metal that have shown wide promise in many fields. Beyond wireless sensing and drug delivery, they are poised to improve optical technologies. Fiber optic ...
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Mobile devices such as cell phones are used increasingly to connect to computer networks such as the Internet for Web browsing, email communication, voice-over-IP (VoIP) telephone and other Internet s...
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Time-frequency analysis involves detecting when oscillations of certain frequencies turn on and off. This kind of analysis is useful in nearly every field of science and engineering. The traditional a...
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In applications such as military vehicles, ultrawide band antennas are needed to operate at very low frequencies. At such frequencies, the electromagnetic wavelength is very large. Consequently, any a...
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