Walter Rotman
Encyclopedia
Walter Rotman was a Jewish American scientist known for his work in radar
and antenna
design. Among his inventions were the Rotman lens, the sandwich wire antenna, and the trough waveguide
.
where he received his BSc
and MSc
. In 1948, he joined the research laboratories of the Air-Force (AFRL
) where he became the branch chief of a laboratory concentrating on investigating the effect of plasma on re-entry vehicles. In 1980, he retired from AFRL
and joined MIT Lincoln Laboratory
where he worked on reflector antennas
until his retirement in 1990. He died on May 19, 2007 at the age of 84 in Boston MA.
systems around the world.
and stripline
to create an antenna.
s less than one. It is considered today as a classic paper as it showed the potential of artificial dielectrics
. In this paper, Rotman reached equations in a relatively simple manner which were derived again twenty years later. However, Rotman did not attempt to use these grids to simulate negative epsilon material, possibly because he saw the difficulties with dispersion and loss which would occur.
Rotman was awarded many honors. He was elected an IEEE Fellow
in 1968 for contributions to antenna technology, He received the IEEE Centennial Medal
in 1984 and the USAF Decoration for Exceptional Civilian Service in 1980, and in 2005 he received the John Kraus Antenna Award.
Radar
Radar is an object-detection system which uses radio waves to determine the range, altitude, direction, or speed of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. The radar dish or antenna transmits pulses of radio...
and antenna
Antenna (radio)
An antenna is an electrical device which converts electric currents into radio waves, and vice versa. It is usually used with a radio transmitter or radio receiver...
design. Among his inventions were the Rotman lens, the sandwich wire antenna, and the trough waveguide
Waveguide
A waveguide is a structure which guides waves, such as electromagnetic waves or sound waves. There are different types of waveguides for each type of wave...
.
Biography
Walter Rotman was born on August 24, 1922 in St. Louis Missouri. He served in the United States Air Force during World War two as a technician for the radar division. After the War, he studied electrical engineering at MITMassachusetts Institute of Technology
The Massachusetts Institute of Technology is a private research university located in Cambridge, Massachusetts. MIT has five schools and one college, containing a total of 32 academic departments, with a strong emphasis on scientific and technological education and research.Founded in 1861 in...
where he received his BSc
Bachelor of Science
A Bachelor of Science is an undergraduate academic degree awarded for completed courses that generally last three to five years .-Australia:In Australia, the BSc is a 3 year degree, offered from 1st year on...
and MSc
Master of Science
A Master of Science is a postgraduate academic master's degree awarded by universities in many countries. The degree is typically studied for in the sciences including the social sciences.-Brazil, Argentina and Uruguay:...
. In 1948, he joined the research laboratories of the Air-Force (AFRL
Air Force Research Laboratory
The Air Force Research Laboratory is a scientific research organization operated by the United States Air Force Materiel Command dedicated to leading the discovery, development, and integration of affordable aerospace warfighting technologies; planning and executing the Air Force science and...
) where he became the branch chief of a laboratory concentrating on investigating the effect of plasma on re-entry vehicles. In 1980, he retired from AFRL
Air Force Research Laboratory
The Air Force Research Laboratory is a scientific research organization operated by the United States Air Force Materiel Command dedicated to leading the discovery, development, and integration of affordable aerospace warfighting technologies; planning and executing the Air Force science and...
and joined MIT Lincoln Laboratory
Lincoln Laboratory
MIT Lincoln Laboratory, located in Lexington, Massachusetts, is a United States Department of Defense research and development center chartered to apply advanced technology to problems of national security. Research and development activities focus on long-term technology development as well as...
where he worked on reflector antennas
Reflector (antenna)
An antenna reflector is a device that reflects electromagnetic waves.It is often a part of an antenna assembly.The most common reflector types are...
until his retirement in 1990. He died on May 19, 2007 at the age of 84 in Boston MA.
Rotman Lens
Rotman is best known for the lens named after him, the Rotman lens. The lens allows radar systems to simultaneously see targets in multiple directions (mutli-beam capability) without physically moving the antenna system. This lens is now integrated into many radars and EWElectronic warfare
Electronic warfare refers to any action involving the use of the electromagnetic spectrum or directed energy to control the spectrum, attack an enemy, or impede enemy assaults via the spectrum. The purpose of electronic warfare is to deny the opponent the advantage of, and ensure friendly...
systems around the world.
Surface Wave Antennas
Rotman invented many types of surface wave antennas including the trough waveguide, the channel waveguide, and the sandwich wire antenna. These periodic structures which he analyzed together with Arthur Oliner allow antennas to scan in various directions by changing frequencies. The sandwich wire antenna was one of the first attempts to use the then-new techniques of microstripMicrostrip
Microstrip is a type of electrical transmission line which can be fabricated using printed circuit board technology, and is used to convey microwave-frequency signals. It consists of a conducting strip separated from a ground plane by a dielectric layer known as the substrate. Microwave components...
and stripline
Stripline
Stripline is a transverse electromagnetic transmission line medium, that was invented by Robert M. Barrett of the Air Force Cambridge Research Centre in the 1950s.- Description :...
to create an antenna.
Metamaterials
Building upon previous work, Rotman used a grid of three-dimensional thin wires to simulate plasmas with dielectric constantDielectric constant
The relative permittivity of a material under given conditions reflects the extent to which it concentrates electrostatic lines of flux. In technical terms, it is the ratio of the amount of electrical energy stored in a material by an applied voltage, relative to that stored in a vacuum...
s less than one. It is considered today as a classic paper as it showed the potential of artificial dielectrics
Artificial dielectrics
Artificial dielectrics are artificial electromagnetic materials consisting of arrayed, synthetic substances. The arrays themselves, and the distances between synthetic substances are usually evenly spaced on, or within, a substrate. Hence, the arrays of inclusions are in a periodic or lattice...
. In this paper, Rotman reached equations in a relatively simple manner which were derived again twenty years later. However, Rotman did not attempt to use these grids to simulate negative epsilon material, possibly because he saw the difficulties with dispersion and loss which would occur.
Published Works and Achievements
Rotman wrote several classic works and papers on the interference of radar plasma on re-entry vehicles and on simulation of plasmas via a grid of thin rods which was an early inspiration for today's work on metamaterials.Rotman was awarded many honors. He was elected an IEEE Fellow
IEEE Fellow
An IEEE member is elevated to the grade of IEEE Fellow for "unusual distinction in the profession and shall be conferred by the Board of Directors upon a person with an extraordinary record of accomplishments in any of the IEEE fields of interest"...
in 1968 for contributions to antenna technology, He received the IEEE Centennial Medal
IEEE Centennial Medal
The IEEE Centennial Medal was a medal minted and awarded in 1984 to celebrate the Centennial of the founding of the Institute of Electrical and Electronics Engineers in 1884.The medal obverse shows 1884 in calligraphic writing and 1984 in an LCD font...
in 1984 and the USAF Decoration for Exceptional Civilian Service in 1980, and in 2005 he received the John Kraus Antenna Award.
External links
- Rotman Lens from Microwaves101.com - Microwave Encyclopedia
- Rotman Lens Patent from Google Patents
- Sandwich Wire Antenna Patent from Google Patents
- Trough Waveguide Patent from Google Patents