Microwave is a form of electromagnetic radiation with wavelengths ranging from about 30 centimeters to one millimeter corresponding to frequencies between 1 GHz and 300 GHz respectively. Different sources define different frequency ranges as microwaves; the above broad definition includes UHF, SHF and EHF bands. A more common definition in radio-frequency engineering is the range between 1 and 100 GHz. In all cases, microwaves include the entire SHF band at minimum. Frequencies in the microwave range are often referred to by their IEEE radar band designations: S, C, X, Ku, K, or Ka band, or by similar NATO or EU designations.
Neuromorphic computing is an approach to computing that is inspired by the structure and function of the human brain. A neuromorphic computer/chip is any device that uses physical artificial neurons to do computations. In recent times, the term neuromorphic has been used to describe analog, digital, mixed-mode analog/digital VLSI, and software systems that implement models of neural systems. The implementation of neuromorphic computing on the hardware level can be realized by oxide-based memristors, spintronic memories, threshold switches, transistors, among others. Training software-based neuromorphic systems of spiking neural networks can be achieved using error backpropagation, e.g., using Python based frameworks such as snnTorch, or using canonical learning rules from the biological learning literature, e.g., using BindsNet.
A metamaterial is any material engineered to have a property that is rarely observed in naturally occurring materials. They are made from assemblies of multiple elements fashioned from composite materials such as metals and plastics. These materials are usually arranged in repeating patterns, at scales that are smaller than the wavelengths of the phenomena they influence. Metamaterials derive their properties not from the properties of the base materials, but from their newly designed structures. Their precise shape, geometry, size, orientation and arrangement gives them their smart properties capable of manipulating electromagnetic waves: by blocking, absorbing, enhancing, or bending waves, to achieve benefits that go beyond what is possible with conventional materials.
Udupi Ramachandra Rao was an Indian space scientist and former chairman of the Indian Space Research Organisation. He was also the Chairman of the Governing Council of the Physical Research Laboratory at Ahmedabad and Nehru Planetarium at Bengaluru and chancellor of the Indian Institute for Space Science and Technology (IIST) at Thiruvananthapuram. He is known as "The Satellite Man of India". He pioneered India's first satellite launch Aryabhata in 1975.
Nader Engheta is an Iranian-American scientist. He has made pioneering contributions to the fields of metamaterials, transformation optics, plasmonic optics, nanophotonics, graphene photonics, nano-materials, nanoscale optics, nano-antennas and miniaturized antennas, physics and reverse-engineering of polarization vision in nature, bio-inspired optical imaging, fractional paradigm in electrodynamics, and electromagnetics and microwaves.
A split-ring resonator (SRR) is an artificially produced structure common to metamaterials. Its purpose is to produce the desired magnetic susceptibility in various types of metamaterials up to 200 terahertz.
G. Madhavan Nair is an Indian space scientist and a former Chairman of the Indian Space Research Organisation, and Secretary to the Department of Space, Government of India. He has also been the Chairman of the Space Commission and Chairman of the Governing Body of the Antrix Corporation, Bangalore.
Koodli Nanjunda Ghanapathi Shankara was a space scientist from India. He was the Director of ISRO's Space Applications Centre (SAC), Ahmedabad and ISRO Satellite Centre (ISAC), Bangalore. He was the Director of Satellite Communications Program Office and Program Director, INSAT, and was looking after overall planning and direction of communication satellite program. His work in the field of transponder design and development led to a boost in India's communication satellite technology.
Negative-index metamaterial or negative-index material (NIM) is a metamaterial whose refractive index for an electromagnetic wave has a negative value over some frequency range.
A terahertz metamaterial is a class of composite metamaterials designed to interact at terahertz (THz) frequencies. The terahertz frequency range used in materials research is usually defined as 0.1 to 10 THz.
Metamaterial antennas are a class of antennas which use metamaterials to increase performance of miniaturized antenna systems. Their purpose, as with any electromagnetic antenna, is to launch energy into free space. However, this class of antenna incorporates metamaterials, which are materials engineered with novel, often microscopic, structures to produce unusual physical properties. Antenna designs incorporating metamaterials can step-up the antenna's radiated power.
A tunable metamaterial is a metamaterial with a variable response to an incident electromagnetic wave. This includes remotely controlling how an incident electromagnetic wave interacts with a metamaterial. This translates into the capability to determine whether the EM wave is transmitted, reflected, or absorbed. In general, the lattice structure of the tunable metamaterial is adjustable in real time, making it possible to reconfigure a metamaterial device during operation. It encompasses developments beyond the bandwidth limitations in left-handed materials by constructing various types of metamaterials. The ongoing research in this domain includes electromagnetic materials that are very meta which mean good and has a band gap metamaterials (EBG), also known as photonic band gap (PBG), and negative refractive index material (NIM).
Thekkethil Kochandy Alex is an Indian space scientist. He was the director of the ISRO Satellite Centre (ISAC) of Indian Space Research Organisation (ISRO) (2008–2012) and Member, Space Commission. He specialized in electro-optic systems and satellite technology. Starting with the first Indian satellite Aryabhata, he has been responsible for the sensor systems in all the Indian satellites. Under his leadership the Laboratory for Electro Optics Systems (LEOS) was established in 1993 and from the inception he was its director till 2008. He was conferred "Dr. Vikram Sarabhai Distinguished Professorship" in 2011.
A photonic metamaterial (PM), also known as an optical metamaterial, is a type of electromagnetic metamaterial, that interacts with light, covering terahertz (THz), infrared (IR) or visible wavelengths. The materials employ a periodic, cellular structure.
The history of metamaterials begins with artificial dielectrics in microwave engineering as it developed just after World War II. Yet, there are seminal explorations of artificial materials for manipulating electromagnetic waves at the end of the 19th century. Hence, the history of metamaterials is essentially a history of developing certain types of manufactured materials, which interact at radio frequency, microwave, and later optical frequencies.
Electronic engineering is a sub-discipline of electrical engineering that emerged in the early 20th century and is distinguished by the additional use of active components such as semiconductor devices to amplify and control electric current flow. Previously electrical engineering only used passive devices such as mechanical switches, resistors, inductors, and capacitors.
Prem Shanker Goel is an Indian space scientist, former secretary at the Department of Ocean Development, Ministry of Earth Sciences, Government of India and a former director of Indian Space Research Organization. He was honored by the Government of India, in 2001, with the fourth highest Indian civilian award of Padma Shri.
Debatosh Guha is an Indian researcher and educator. He is a Professor at the Institute of Radio Physics and Electronics at the Rajabazar Science College, University of Calcutta. He is an Adjunct faculty at the National Institute of Technology Jaipur and had also served Indian Institute of Technology Kharagpur as HAL Chair Professor for a period during 2015-2016.
Distributed-element circuits are electrical circuits composed of lengths of transmission lines or other distributed components. These circuits perform the same functions as conventional circuits composed of passive components, such as capacitors, inductors, and transformers. They are used mostly at microwave frequencies, where conventional components are difficult to implement.
Prof. Siddheshwari Prasad Chakravarti was an Indian engineer, researcher, and educator. He was known as the father of electronics and telecommunications engineering in India.
