Terahertz Technology: Transforming Military Wireless, Aircraft, and Space Communications

Rajesh Uppal March 24, 2024 Electronics & EW Comments Off on Terahertz Technology: Transforming Military Wireless, Aircraft, and Space Communications 1,399 Views

Introduction:

In an era where data is king, communication technologies are at the forefront of military and aerospace advancements. Speed, security, and reliability are non-negotiable in these domains. In the rapidly evolving landscape of wireless communication, the demand for faster, more reliable data transfer is escalating. The world is shifting towards an era where staying connected to the internet, regardless of location, is the norm. The explosion of data usage is staggering, with the internet protocol traffic expected to soar beyond 130 exabytes per month. Meeting this demand for high-quality data at high speeds is a priority for various sectors, particularly the military, aircraft, and space industries.

To meet these demands, researchers and engineers are turning to the incredible capabilities of terahertz technology. Terahertz waves, sitting between microwave and infrared in the electromagnetic spectrum, hold the potential to revolutionize communication in the military, aircraft, and space sectors, promising terabits per second data transfer rates. With its vast spectrum, THz offers several advantages over traditional radio frequencies, including significantly higher data rates, wider bandwidth, enhanced security, and reduced latency. In this article, we’ll explore how terahertz technology is shaping the future of these critical communication systems.

The Era of Exponential Data Growth

With wireless data traffic on the rise, the need for high-speed communication has never been more critical. People expect instant access to vast amounts of information, including high-quality videos and real-time data, wherever they go. The burgeoning video traffic, set to dominate the data landscape, poses significant challenges to existing wireless networks, including the ongoing deployment of 5G networks. For example, virtual reality (VR) devices are estimated to require data rates of at least 10 Gbps, and 4K and 8K ultra-high-definition (UHD) video and 3-D rendering will soon become the norm. Uncompressed UHD video can demand data rates of up to 24 Gbps, while an uncompressed 3-D UHD video can reach a staggering 100 Gbps. Predictions even point to the possibility of achieving terabit-per-second (Tbps) data rates in the next decade.

The existing wireless technology struggles to support Tbps links. Cutting-edge communication systems utilizing ultra-wideband (UWB) or millimeter wave (mmWave) technology can only achieve gigabit-per-second (Gbps) rates. Meanwhile, communication via infrared (IR) or visible light (VLC) faces technical and safety limitations.

Terahertz: Unleashing Next-Gen Communication

To overcome these limitations and achieve the coveted Tbps data rates, researchers are turning to terahertz technology. The terahertz spectrum, spanning 0.1–10 THz, offers frequencies a hundredfold higher than mmWave, addressing spectrum scarcity and capacity limitations in current wireless systems. In theory, terahertz Wi-Fi could support data rates of up to 100 Gbps within a range of approximately 10 meters.

In the past, the terahertz spectrum (0.3–3 THz) was considered the “Terahertz Gap” due to its unavailability for electronic or photonic means. Traditional electronic devices couldn’t operate at its lowest frequency, while photonic devices could only function beyond its highest frequency. However, continuous progress is being made in developing terahertz components and devices to overcome these barriers. However continuous progress is being made for Terahertz components and devices to overcome electronic/photonic barriers for realizing highly integrated Terahertz systems.

“Imaging, radar, spectroscopy, and communications systems that operate in the millimeter-wave (MMW) and sub-MMW bands of the electromagnetic spectrum have been difficult to develop because of technical challenges associated with generating, detecting, processing and radiating the high-frequency signals associated with these wavelengths. To control and manipulate radiation in this especially challenging portion of the RF spectrum, new electronic devices must be developed that can operate at frequencies above one Terahertz (THz), or one trillion cycles per second,” says DARPA.

1. Blazing Fast Data Rates:

Terahertz waves offer data transfer rates that are orders of magnitude faster than current wireless technologies. With speeds potentially reaching terabits per second, they can facilitate rapid information exchange between military units, aircraft, and spacecraft.

2. Ultra-Low Latency:

For military operations and aerospace missions, low latency is a game-changer. Terahertz waves can provide near-instantaneous data transmission, allowing for real-time decision-making, navigation, and control.

3. Immunity to Interference:

Terahertz waves operate at such high frequencies that they are less susceptible to interference from other electronic devices and can be highly secure, making them ideal for military communications.

Terahertz Applications

Information Showers: In high-traffic areas like metro entrances or shopping malls, terahertz access points can provide users with rapid data downloads. This allows seamless delivery of software updates and heavy traffic like high-quality videos.
Mobile Access: Despite propagation losses, terahertz communications can be used to create reliable wireless links for tens of meters, with data rates of tens of gigabits per second, making terahertz access points feasible.
Fiber-Equivalent Wireless Links: Experimental validation has shown the feasibility of multi-gigabit-per-second wireless links in the lower terahertz band over distances of up to 1 km. These links are crucial for future wireless networks.
Connectivity with Miniature Devices: Terahertz transceivers enable networking of micro- and nano-scale robots, aiding society in various fields, from environmental sensing to medicine.

Terahertz for Future Military and Space Communications

In the military domain, THz technology holds immense potential for enhancing battlefield communications and situational awareness. In military applications, terahertz wireless sensor networks offer secure gigabit battlefield wireless sensor networks and multi-sensor fusion. Its ability to penetrate various materials, such as smoke and fog, enables reliable communication even in challenging environments. Moreover, THz’s high data rates facilitate the transmission of large volumes of data, such as high-definition video and real-time sensor data, crucial for tactical decision-making.

Terahertz networks are hard to intercept due to their limited transmission range and highly directional antennas. They can form ad hoc networks in the battlefield to connect soldiers and equipment securely.

Additionally, THz technology’s inherent security features make it ideal for military communications. Its high frequencies are difficult to intercept or jam, providing a secure and reliable means of exchanging sensitive information.

In space, terahertz communication is lossless, offering secure gigabit aircraft-to-satellite communication with minimal power requirements. The enhanced bandwidth supports ultra-wideband Code Division Multiple Access (CDMA) communication schemes with high immunity to fading, low probability of detection, and interception.

Military Applications:

1. Secure Communication:

The military relies on secure and fast communication for coordination and data exchange between various units. Terahertz technology can provide encrypted communication channels that are resistant to jamming and eavesdropping.

2. Drone Networks:

Unmanned aerial vehicles (UAVs) are becoming increasingly vital in modern warfare. Terahertz communication enables these drones to share critical data quickly, improving mission success.

Aircraft Communication:

THz technology is also poised to revolutionize aircraft communications. With its ability to support gigabit-per-second data rates, THz can enable seamless in-flight connectivity, facilitating real-time data exchange between aircraft and ground stations. This real-time data transfer is critical for applications such as air traffic control, remote diagnostics, and in-flight entertainment.

Furthermore, THz technology can enhance aircraft safety by enabling secure communication between aircraft and ground stations during emergencies. Its high data rates allow for the transmission of large amounts of critical information, such as flight data and sensor readings, in real-time, facilitating rapid response and incident management.

1. Lightning-Fast In-Flight Entertainment:

Passenger expectations for in-flight entertainment are soaring. Terahertz technology can provide seamless streaming and high-speed internet to aircraft, ensuring a satisfying travel experience.

2. Air Traffic Control:

For safer skies, aircraft must communicate swiftly with air traffic control. Terahertz communication systems can reduce delays and enhance the efficiency of air traffic management.

Space Communication:

THz technology has the potential to transform space communications by enabling high-speed data transmission between satellites and ground stations. Its wide bandwidth can accommodate the increasing demand for data from orbiting satellites, supporting applications such as Earth observation, satellite navigation, and deep space exploration.

Additionally, THz technology can enable secure communication between satellites, facilitating the exchange of sensitive information without the risk of interception. This secure communication is crucial for military and government applications in space.

1. Deep Space Exploration:

As we venture further into space, the need for high-speed, reliable communication becomes paramount. Terahertz waves can transmit data over vast distances with minimal signal degradation.

2. Satellite Networks:

Satellites play a crucial role in Earth observation, weather forecasting, and global communication. Terahertz technology enhances the speed and efficiency of satellite networks, contributing to the accuracy of these services.

A single THz satellite communication link will support broadband data transfer rates far beyond (>20X) the limits of current microwave technology. The easier pointing due to their wider beam width, it is suitable for the application in the GEO-GEO or LEO-GEO inter-satellite links, which can support the high-throughput (Gigabit) communication with high security as well as the ability to defeat the interference.

Noteworthy Achievements

Researchers from Hiroshima University, Panasonic Corporation, and the National Institute of Information and Communications Technology have developed a terahertz (THz) transmitter capable of transmitting data at speeds exceeding 100 gigabits per second (0.1 terabit) within the 300-GHz band. This technology, which demonstrated six times higher per-channel data rates, opens up the potential for ultrahigh-speed satellite links, significantly improving in-flight network speeds. It could also facilitate rapid content downloads to mobile devices and provide ultrafast wireless connections between base stations. These terahertz wireless links have the potential to surpass optical fibers by reducing data latency and achieving light-speed minimum-latency links. The unallocated frequency range used falls between 275-450 GHz, which is to be discussed at the World Radiocommunication Conference (WRC) 2019 under the International Telecommunication Union Radiocommunication Section (ITU-R).

FUJITSU and NTT have jointly developed a compact 300GHz receiver operating within the terahertz waveband. This technology enables wireless communication at speeds of multiple gigabits per second, making it ideal for small devices. The integrated module combines a receiver-amplifier chip and a terahertz-band antenna, housed within a small 0.75 cm3 volume, suitable for mobile devices. It employs a low-loss polyimide material to connect the antenna and receiver-amplifier chip, significantly reducing signal loss compared to traditional materials like ceramic, quartz, or Teflon. This breakthrough has the potential to enable instant 4K or 8K HD video downloads and facilitate rapid data transfers between mobile devices and servers.

The Tokyo Institute of Technology achieved a 3 Gbps transmission at 542 GHz.

During the 2008 Olympic Games, scientists from Osaka University and NTT Corp. demonstrated a 120 GHz data link spanning 1 km.

NTT has developed a wireless-use integrated circuit (IC) designed for ultrahigh-speed short-distance wireless communications. This IC incorporates a modulator and a power amplifier, both crucial components for wireless transmission. By implementing multi-parallelization of the amplifier, they achieved high output power and low-loss wiring, allowing for high data rates. The use of a travelling-wave modulator further enhances data speed. Additionally, the IC incorporates a low-loss and wideband waveguide-to-IC transition design, minimizing any negative impact on its characteristics due to packaging. The IC successfully achieved high-speed operation, delivering data rates of up to 20 gigabits per second (Gbit/s).

In recent years, there have been several significant breakthroughs in THz communication technology. These breakthroughs include:

The development of high-power THz transmitters: THz transmitters have traditionally been very low power, which has limited the range of THz communication systems. However, researchers have recently developed THz transmitters that can generate much higher power levels. This breakthrough will allow THz communication systems to operate over longer distances.
The development of wide-bandwidth THz transceivers: THz transceivers have also traditionally had very narrow bandwidths. This has limited the amount of data that can be transmitted over THz links. However, researchers have recently developed THz transceivers with much wider bandwidths. This breakthrough will allow THz communication systems to support higher data rates.
The development of new THz signal processing techniques: New THz signal processing techniques have been developed that make it possible to transmit and receive THz signals with greater efficiency. This breakthrough will improve the performance of THz communication systems.
The development of new THz antennas: New THz antennas have been developed that are more efficient and have better directivity than traditional THz antennas. This breakthrough will improve the range and performance of THz communication systems.

These breakthroughs are paving the way for the development of next-generation THz communication systems that will have a wide range of applications in military, commercial, and scientific fields.

Here are some of the potential applications of THz communication technology:

High-definition video transmission: THz communication technology can be used to transmit high-definition video signals wirelessly. This would allow for the development of new applications, such as real-time virtual reality and augmented reality experiences.
Secure communications: THz communication technology can be used to transmit secure communications signals. This would be ideal for applications that require the highest level of security, such as military and government communications.
Medical imaging: THz communication technology can be used to develop new medical imaging devices that can provide high-resolution images of the human body. This would be valuable for applications such as cancer diagnosis and treatment monitoring.
Scientific research: THz communication technology can be used to develop new scientific instruments that can study the behavior of materials at the atomic and molecular level. This would be valuable for a wide range of scientific research fields, such as chemistry, physics, and biology.

Terahertz technology is on the cusp of revolutionizing wireless communication. Its potential applications range from high-speed data transfers on Earth to seamless communication in outer space. As researchers continue to innovate, we can anticipate a future where the terahertz spectrum drives the next generation of wireless technology, exceeding our current expectations for speed and reliability.

The Air Force Research Laboratory Information Directorate (AFRL RI) has initiated the Ultra-Broadband Terahertz Radio Development (UBTRD) project in Rome, New York.

This ambitious project aims to advance wireless communication systems by developing novel ultra-broadband terahertz (THz) radio technologies. Operating within the 0.1 to 10 THz frequency range, THz radio waves offer an extensive spectrum compared to traditional radio frequencies, presenting opportunities for high-speed data transmission, wideband imaging, and secure communications.

Current THz transceiver technologies confront limitations in terms of power, bandwidth, and operating range. The USTRD project sets out to develop THz transceivers that can achieve high power (transmitters capable of 100 milliwatts output), wide bandwidth (systems operating over at least 1 THz continuous bandwidth), and extended range (transmitting and receiving THz signals over a distance of at least 100 meters). To achieve these goals, the AFRL RI is actively seeking industry proposals that can contribute to the advancement of ultra-broadband THz radio technologies. Proposals are encouraged across a spectrum of areas, including THz transceiver architectures and components, signal processing techniques, and practical applications in high-speed data transmission, imaging, and secure communications.

The USTRD project, anticipated to continue until 2028, will fund selected proposals through a competitive review process, with projects receiving resources for up to three years. Successful development of ultra-broadband THz radio technologies has the potential to bring about transformative changes in wireless communication systems. This includes enabling gigabit and terabit per second data rates, high-resolution imaging for security screening and medical diagnostics, and secure and jamming-resistant communications for military and government use.

Furthermore, the USTRD project opens the door to new applications, such as real-time industrial process monitoring, remote environmental sensing for disaster relief, and non-destructive material testing and evaluation. In essence, the project is a significant step towards advancing THz radio technologies, with the potential to revolutionize communication systems and introduce a multitude of innovative applications. Through industry collaboration, the AFRL RI is paving the way for a future where THz technologies play a transformative role in society

Challenges and Future Prospects:

While terahertz technology holds enormous promise, it is not without its challenges. These include the need for precise alignment of equipment, atmospheric absorption, and the development of compact and energy-efficient terahertz transmitters and receivers. As researchers continue to address these challenges, terahertz communication systems are expected to become increasingly prevalent in military, aircraft, and space applications.

Conclusion:

Terahertz technology represents a seismic shift in the realm of communication for the military, aircraft, and space exploration. With its unparalleled data rates, low latency, and security, it opens up a new world of possibilities. As we move toward a future characterized by terabits per second data transfer, these applications promise to make our world safer, more efficient, and more connected than ever before.

References and Resources also include:

http://www.fbh-berlin.com/research/iii-v-technology/inp-devices

http://www.ntt.co.jp/dtl/e/technology/pe_product-terahertz-v7.html