Ali Hajimiri | |
---|---|
Nationality | Iranian American |
Alma mater | Sharif University of Technology (B.S.) Stanford University (M.S., Ph.D.) |
Awards | Feynman Prize for Excellence in Teaching (2019); [1] Microwave Prize (2015) |
Scientific career | |
Fields | Electrical Engineering |
Institutions | California Institute of Technology |
Doctoral advisor | Thomas H. Lee Bruce A. Wooley |
Ali Hajimiri is an academic, entrepreneur, and inventor in various fields of engineering, including electrical engineering and biomedical engineering. He is the Bren Professor of Electrical Engineering and Medical Engineering at the California Institute of Technology (Caltech).
Hajimiri received the B.S. degree in electrical engineering from Sharif University of Technology and his M.S. and Ph.D. degrees in electrical engineering from Stanford University. He has also worked for Bell Laboratories, Philips Semiconductors, and Sun Microsystems. As a part of his Ph.D. thesis, he developed a time-varying phase noise model for electrical oscillators, [2] also known as the Hajimiri phase noise model. [3]
In 2002, together with his former students Ichiro Aoki and Scott Kee, he cofounded Axiom Microdevices Inc. based on their invention of the Distributed Active Transformer (DAT), which made it possible to integrate RF CMOS power amplifiers suitable for cellular phones in CMOS technology. Axiom shipped hundreds of millions of units [ citation needed ] before it was acquired by Skyworks Solutions in 2009.
He and his students also demonstrated the world's first radar-on-a-chip in silicon technology in 2004, [4] showing a 24-GHz 8-element phased array receiver [5] and a 4-element phased array transmitter in CMOS. [6] These were followed by a 77-GHz phased array transceiver (transmitter and receiver) with on chip antennas that established the highest level of integration in mm-wave frequency applications and was a complete radar-on-a-chip. [7] [8] They also developed a fully scalable phased array architecture in 2008, making it possible to realize very-large-scale phased arrays. [9]
He and his team are also responsible for the development of an all-silicon THz imager system, where an integrated CMOS microchip was used in conjunction with a second silicon microchip to form an active THz imaging system, capable of seeing through opaque objects. They demonstrated various phased array transmitters around 0.3THz with beam steering using the distributed active radiator (DAR) architecture in 2011. [10] Various applications of this system appear in security, communications, medical diagnostics, and the human-machine interface. [11] [12] [13]
In 2013, he and some of his team members demonstrated a complete self-healing power amplifier, which through an integrated self-healing strategy, could recover from various kinds of degradation and damage including aging, local failure, and intentional laser blasts. [14] [15] [16] [17]
Between 2014 and 2018, his lab demonstrated several major advances in imaging, projection, and sensing technology on silicon photonic platforms. [18] [19] [20] In 2014, they showed the first silicon nanophotonic optical phased array transmitter capable of dynamic and real-time image projection, therefore serving as a lensless projector. [21] [22] In 2015, he and his group constructed a 3D coherent camera via a silicon nanophotonic coherent imager (NCI) that performed direct 3D imaging at meter range with a 15-micron depth resolution. [23] [24] In 2016, they devised and implemented a one-dimensional (1D) integrated optical phased array receiver which could image a barcode directly from the surface of a chip, [25] followed in 2017 by an integrated two-dimensional (2D) optical phased array receiver capable of imaging simple 2D patterns without a lens using a very thin optical synthetic aperture of a few microns, thereby demonstrating a lensless flat camera for the first time. [26] [27] In 2018, they demonstrated the world's first all-integrated optical gyroscope, whose principle of operation is based on the Sagnac effect. [28] [29] [30] [31] [32]
He and his team have also developed systems and technologies for wireless power transfer at a distance. In 2017, he co-founded GuRu Wireless (formerly Auspion, Inc.), which commercializes wireless power transfer technology for consumers. [33] [34]
He holds more than 160 issued U.S. patents. [41]
An integrated circuit or monolithic integrated circuit is a set of electronic circuits on one small flat piece of semiconductor material, usually silicon. Large numbers of miniaturized transistors and other electronic components are integrated together on the chip. This results in circuits that are orders of magnitude smaller, faster, and less expensive than those constructed of discrete components, allowing a large transistor count. The IC's mass production capability, reliability, and building-block approach to integrated circuit design have ensured the rapid adoption of standardized ICs in place of designs using discrete transistors. ICs are now used in virtually all electronic equipment and have revolutionized the world of electronics. Computers, mobile phones and other home appliances are now inextricable parts of the structure of modern societies, made possible by the small size and low cost of ICs such as modern computer processors and microcontrollers.
In antenna theory, a phased array usually means an electronically scanned array, a computer-controlled array of antennas which creates a beam of radio waves that can be electronically steered to point in different directions without moving the antennas.
Photonics is a branch of optics that involves the application of generation, detection, and manipulation of light in form of photons through emission, transmission, modulation, signal processing, switching, amplification, and sensing. Photonics is closely related to quantum electronics, where quantum electronics deals with the theoretical part of it while photonics deal with its engineering applications. Though covering all light's technical applications over the whole spectrum, most photonic applications are in the range of visible and near-infrared light. The term photonics developed as an outgrowth of the first practical semiconductor light emitters invented in the early 1960s and optical fibers developed in the 1970s.
Terahertz radiation – also known as submillimeter radiation, terahertz waves, tremendously high frequency (THF), T-rays, T-waves, T-light, T-lux or THz – consists of electromagnetic waves within the ITU-designated band of frequencies from 0.3 to 3 terahertz (THz), although the upper boundary is somewhat arbitrary and is considered by some sources as 30 THz. One terahertz is 1012 Hz or 1000 GHz. Wavelengths of radiation in the terahertz band correspondingly range from 1 mm to 0.1 mm = 100 µm. Because terahertz radiation begins at a wavelength of around 1 millimeter and proceeds into shorter wavelengths, it is sometimes known as the submillimeter band, and its radiation as submillimeter waves, especially in astronomy. This band of electromagnetic radiation lies within the transition region between microwave and far infrared, and can be regarded as either.
A rectenna is a special type of receiving antenna that is used for converting electromagnetic energy into direct current (DC) electricity. They are used in wireless power transmission systems that transmit power by radio waves. A simple rectenna element consists of a dipole antenna with a diode connected across the dipole elements. The diode rectifies the AC induced in the antenna by the microwaves, to produce DC power, which powers a load connected across the diode. Schottky diodes are usually used because they have the lowest voltage drop and highest speed and therefore have the lowest power losses due to conduction and switching. Large rectennas consist of an array of many power receiving elements such as dipole antennas.
Liquid crystal on silicon is a miniaturized reflective active-matrix liquid-crystal display or "microdisplay" using a liquid crystal layer on top of a silicon backplane. It is also referred to as a spatial light modulator. LCoS was initially developed for projection televisions but is now used for wavelength selective switching, structured illumination, near-eye displays and optical pulse shaping. By way of comparison, some LCD projectors use transmissive LCD, allowing light to pass through the liquid crystal.
An image sensor or imager is a sensor that detects and conveys information used to form an image. It does so by converting the variable attenuation of light waves into signals, small bursts of current that convey the information. The waves can be light or other electromagnetic radiation. Image sensors are used in electronic imaging devices of both analog and digital types, which include digital cameras, camera modules, camera phones, optical mouse devices, medical imaging equipment, night vision equipment such as thermal imaging devices, radar, sonar, and others. As technology changes, electronic and digital imaging tends to replace chemical and analog imaging.
Nanophotonics or nano-optics is the study of the behavior of light on the nanometer scale, and of the interaction of nanometer-scale objects with light. It is a branch of optics, optical engineering, electrical engineering, and nanotechnology. It often involves dielectric structures such as nanoantennas, or metallic components, which can transport and focus light via surface plasmon polaritons.
An active-pixel sensor (APS) is an image sensor, which was invented by Peter J.W. Noble in 1968, where each pixel sensor unit cell has a photodetector and one or more active transistors. In a metal–oxide–semiconductor (MOS) active-pixel sensor, MOS field-effect transistors (MOSFETs) are used as amplifiers. There are different types of APS, including the early NMOS APS and the now much more common complementary MOS (CMOS) APS, also known as the CMOS sensor. CMOS sensors are used in digital camera technologies such as cell phone cameras, web cameras, most modern digital pocket cameras, most digital single-lens reflex cameras (DSLRs), mirrorless interchangeable-lens cameras (MILCs), and lensless imaging for cells.
Richard "Dick" Francis Lyon is an American inventor, scientist, and engineer. He is one of the two people who independently invented the first optical mouse devices in 1980. He has worked in signal processing and was a co-founder of Foveon, Inc., a digital camera and image sensor company.
A photonic integrated circuit (PIC) or integrated optical circuit is a microchip containing two or more photonic components which form a functioning circuit. This technology detects, generates, transports, and processes light. Photonic integrated circuits utilize photons as opposed to electrons that are utilized by electronic integrated circuits. The major difference between the two is that a photonic integrated circuit provides functions for information signals imposed on optical wavelengths typically in the visible spectrum or near infrared (850–1650 nm).
Silicon photonics is the study and application of photonic systems which use silicon as an optical medium. The silicon is usually patterned with sub-micrometre precision, into microphotonic components. These operate in the infrared, most commonly at the 1.55 micrometre wavelength used by most fiber optic telecommunication systems. The silicon typically lies on top of a layer of silica in what is known as silicon on insulator (SOI).
Phased-array optics is the technology of controlling the phase and amplitude of light waves transmitting, reflecting, or captured (received) by a two-dimensional surface using adjustable surface elements. An optical phased array (OPA) is the optical analog of a radio-wave phased array. By dynamically controlling the optical properties of a surface on a microscopic scale, it is possible to steer the direction of light beams, or the view direction of sensors, without any moving parts. Phased-array beam steering is used for optical switching and multiplexing in optoelectronic devices and for aiming laser beams on a macroscopic scale.
Thomas H. Lee is a professor in the Department of Electrical Engineering at Stanford University. Lee's research focus has been on gigahertz-speed wireline and wireless integrated circuits built in conventional silicon technologies, particularly CMOS; microwave; and RF circuits.
Quilt Packaging (QP) is an integrated circuit packaging and chip-to-chip interconnect packaging technology that utilizes “nodule” structures that extend out horizontally from the edges of microchips to make electrically and mechanically robust chip-to-chip interconnections.
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RF CMOS is a metal–oxide–semiconductor (MOS) integrated circuit (IC) technology that integrates radio-frequency (RF), analog and digital electronics on a mixed-signal CMOS RF circuit chip. It is widely used in modern wireless telecommunications, such as cellular networks, Bluetooth, Wi-Fi, GPS receivers, broadcasting, vehicular communication systems, and the radio transceivers in all modern mobile phones and wireless networking devices. RF CMOS technology was pioneered by Pakistani engineer Asad Ali Abidi at UCLA during the late 1980s to early 1990s, and helped bring about the wireless revolution with the introduction of digital signal processing in wireless communications. The development and design of RF CMOS devices was enabled by van der Ziel's FET RF noise model, which was published in the early 1960s and remained largely forgotten until the 1990s.
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