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RF/microwave technology is finding a home in new fields every year and even creating industries and areas of study. The miniaturization and increased cost efficiency of modern RF/microwave technology allows for wireless enhancement to almost any technological application. Communications electronics, medical sensing/monitoring, and state-of-the-art aircraft are just a few of the fields that are heavily influenced by these enhancements. With the rapidly increasing use of wireless technology, the market is being pushed to develop more advanced materials and methods. In fact, a few categories of materials in particular are creating a buzz around the potential benefits of next-generation wireless technologies.

The first cutting-edge category on the list is a group of conductors that exceed even the highest conductivity potential of copper, silver, or gold. These “superconductors” differ fundamentally from conventional materials in the manner by which electrons move through the material on a quantum level. Such quantum behavioral differences lead to unique properties like zero resistance conduction, high current density, high sensitivity to magnetic fields, and near speed-of-light signal transmission. As noted by Oleg Mukhanov, senior vice president and general manager for Government Operations at HYPRES, Inc., "Superconductivity provides a number of performance advantages, critical for many applications from RF systems, medical systems, to high-end computing."

RF Materials Can Open The Gates For Next-Generation Technology, Fig. 1

When it comes to advancing wireless technologies, superconductors allow for the near-lossless transmission of high-frequency signals with very low external interference. This benefit has huge real-world impact—especially within the telecommunications industry. The division of cellular telephone signals into small channels using modern filters reduces the range and quality of cellular communication. The dissipation of signal energy through imperfect filters and signal processing causes this degradation. In doing so, it leads to a significant cost increase as telecommunications companies require higher-power signal towers or more towers in a network for adequate coverage.

Additionally, imperfect filters require wider bandwidth for each channel, thereby reducing the number of simultaneous connections. Superconductor filters provide near-lossless current flow, perfect diamagnetism, and lack of dispersion, which could increase the number of channels for a standard telecommunications setup while reducing the minimum required strength of the signals for processing.

RF Materials Can Open The Gates For Next-Generation Technology, Fig. 2

With superconductor-enhanced analog-to-digital converters (ADCs), the speed of wireless communications could be enhanced many fold, according to a white paper by HYPRES titled "Benefits of Superconductor Digital-RF Transceiver Technology To Future Wireless Systems." Superconductors provide linearity, quantum accuracy, and near-light-speed transmission intrinsically. This enhancement could completely expunge the need for the digital signal to be analog preprocessed before it is converted into a high-frequency signal, allowing direct digital-to-high-frequency conversion.

With superconductor digital microelectronic circuits operating at speeds near 100 GHz, the frequency and protocol-specific analog hardware in wireless systems can potentially be replaced with flexible, software-programmable digital processors. These benefits could lead to a completely software-defined radio (SDR) that could behave as a universal system, where the hardware could be adapted to almost any platform. Lower receiver noise temperatures would enhance information capacity--even where interference normally limits full-bandwidth utilization. Transmitters also would benefit from being able to generate spectrally pure waveforms with completely linear amplifier chains. The U.S. Government and many commercial ventures are already leading the development of superconductor technologies for wireless communications.

RF Materials Can Open The Gates For Next-Generation Technology, Fig. 3

Such enhancements would also impact the sensing, instrumentation, and radar fields, where superconductors enable the most sensitive detection of electromagnetic (EM) radiation. In addition, the instrumentation field benefits from the extreme magnetic-field sensing capability of superconductor circuits, which can be seen in instruments designed from superconducting quantum interface devices (SQUIDS). From detecting indicators of potential oil fields and salt domes from the air to chemistry, physics, and material-science laboratories, such instruments will continue to allow for cutting-edge advancements. SQUID detectors also are used as the most sensitive EM detectors of space-born signals and are used in several radio observatories around the world. Additionally, the high dynamic range of superconducting digitizers allows for the detection and identification of sea-skimming missiles for anti-ship missile-defense radar.

Many companies, like HYPRES, are already developing high-speed computers and advanced wireless-communications systems using superconducting technologies.  Superconductor Technologies, Inc. (STI) offers several low-noise receiver front ends, duplexers, and antenna multiplexers that use cryogenic superconducting technology. Though superconductors offer potentially huge benefits for the RF/microwave fields, presently there are only a limited number of applications in which the modern superconductor can be used. Cryogenic cooling is needed to ensure proper superconductivity, which is not possible in all applications. As the uses for superconductor technology increase, the need to raise the operating temperature of superconductors has increased as well. Future superconductors could range in size from nanometer connections between transistors all the way to ultra-low-loss, high-power cable lines.

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