Antenna Array Developments: A Perspectiveon the Past, Present and Future

Randy L. Haupt1 and Yahya Rahmat-Samii2

1Department of Electrical Engineering and Computer Science, Colorado School of Mines, Golden, CO 80401 USAE-mail: haupt@ieee.org

2Department of Electrical Engineering, University of California, Los Angeles, Los Angeles, CA 90095 USAE-mail: rahmat@ee.ucla.edu

Abstract

This paper presents a historical development of phased-array antennas as viewed by the authors. Arrays are anotherapproach to high-gain antennas as contrasted with reflector antennas. They originated a little over 100 years ago andreceived little attention at first. WWII elevated their importance through use in air defense. Since then, the developmentof computers and solid-state devices has made arrays a very valuable tool in radio-frequency systems. Radio astronomyand defense applications will continue to push the state of the art for many years.

Keywords: Antenna; arrays; beamforming; history; phased arrays; radar

1. Introduction

Large antennas collect relatively large amounts of elec-tromagnetic energy much as large buckets collect large

amounts of rain. In our companion paper, we described reflec-tor antennas (large buckets). Using many small buckets tocollect rain corresponds to using small antennas in an array tocollect a large amount of electromagnetic energy. As with an-tennas, a large bucket has the advantage of collecting lots ofwater in one location, whereas using many small buckets hasthe advantage of being easy to rearrange and move the smallbuckets in order to better collect the rain. This analogy be-tween buckets and antennas is interesting but limited, becauseelectromagnetic waves have phase whereas rain does not.

Large antennas create the high gain needed to boost thereceived/transmitted signal for a communications or radar sys-tem. Today, reflectors and arrays compete for large aperturejobs in many types of systems. In general, the reflector is rela-tively inexpensive, that is why it is the antenna of choice forcommercial activities, such as satellite TV. If the reflector mustbe moved in order to locate or track a signal, then the gimbals,servomotors, and other mechanical parts become a reliabilityand maintenance issue that significantly increases lifecycle cost.

Moreover, mechanical steering might be too slow to meet someof the demands on fast-moving platforms such as airplanes.

The array, particularly the phased array, makes many per-formance promises but for a price. Some of the unique featuresof a phased-array antenna include:

1. fast wide-angle scanning without moving the antenna;

2. adaptive beamforming;

3. graceful degradation in performance over time;

4. distributed aperture;

5. multiple beams;

6. potential for low radar cross section.

Comparatively, reflectors are blessed with these advantages:

1. high G/T;

2. wide bandwidth;

3. relatively low cost.

The competition between the better antennas for the job will con-tinue with the cost/performance issues decided by the mission

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and budget. Clearly, hybridization of reflectors and arrays pro-vides enhanced opportunity for more sophisticated and high-performance antenna systems.

This paper presents the historical development of arrayantennas. Reflectors have a rich history in optics that startedthousands of years ago. Arrays, on the other hand, are only alittle more than 100 years old, whereas phased arrays are onlya little more than 70 years old. The next section starts aroundthe turn of the 20th century and continues up to WWII. WWII(see Section 3) motivated the development of high-gain anten-nas for defensive reasons. Section 3 continues with develop-ments after WWII up to the computer age. Section 4 describesthe impact of computers on array design and control. Semicon-ductor technology led to the development of very sophisticatedsolid-state arrays described in Section 5. Finally, Section 6 looksto the future. Our account of history is what we have learnedthrough research and experience. The authors decided to collabo-rate on two historical papers based on presentations they madeat the IEEE CLASTECH Symposium and Exhibition on Anten-nas and Microwave Technology, October 2011, Los Angeles, CA.This paper summarizes the presentation made by Randy Haupt:“Phased array antenna design yesterday and today.” A compan-ion paper covers the history of reflector antennas. Due to lim-ited space and our limited knowledge, we apologize to thosewhose important work has been omitted.

2. Early Array Developments: 1899–1937

The first antenna array was built over 100 years ago [1]. Inorder to increase the directivity of a single monopole, Brownused two vertical antennas separated by half a wavelength andfed them out of phase [2]. He found that the directivity wasgreatest in the plane of the antennas. The first array radiatedat endfire. De Forest also noted an increase in gain due to ar-raying two vertical antennas [3]. He and several others usedan array to locate the source of a transmitting station. Shortlyafter the turn of the century, Marconi performed several ex-periments involving multiple antennas to enhance the gain incertain directions [4]. Some even credit him with the inventionof the antenna array, even though other lesser known experi-menters preceded him. Nobel Prize winner Ferdinand Braun(also given credit as the inventor of the antenna array) placedthree monopoles in a triangle, as shown in Figure 1 [5]. Thesignal at antenna C has a 100� phase and twice the amplitude

of the 0� phase signals at A and B. They discovered that thearray radiated a cardioid pattern. Braun was the first to use phaseto collimate (steer) the main beam. Maybe we can say that heis the inventor of the phased array.

The early arrays were physically large but electricallysmall. Thus, an array of only a few elements required extensivereal estate. In 1917, Frank Adcock designed a direction-findingarray (see Figure 2) that consists of four uniformly weighted el-ements placed at the four corners of a square whose sides aremuch less than half of a wavelength [6]. The antennas on onediagonal are out of phase with the antennas on the other diag-onal. Sir Watson-Watt developed the mathematics to find theelevation and azimuth of a source incident on an Adcock array[7]. Adcock arrays are still popular today. The main purpose ofthe first arrays was direction finding.

The magnetron was first developed in 1920 [8]. At first, itonly worked at low frequencies. By 1940, however, the Britishhad it working at high power above 1 GHz. This developmentled to higher resolution antennas and radars on aircraft, henceelectrically larger antenna arrays.

Harold Friis was the dominant array researcher from themid-1920s to the mid-1930s. Friis presented the theory behindthe antenna pattern for a two-element array of loop antennasand experimental results that validated his theory [9]. Friis sub-sequently designed a multiple-unit steerable antenna (MUSA)[10], which employed an array of rhombics and was altered foroptimum reception of shortwave signals (see Figure 3). In 1927,J. S. Stone received a patent for the binomial amplitude taper,which theoretically eliminates array sidelobes [11]. Mutual cou-pling between elements in an array was recognized to be veryimportant in array design at a very early date [12].

3. Arrays in WWII: 1937–1945

WWII motivated countries to tremendously accelerate thedevelopment of radars that detect aircraft and ships at a greatdistance. The radars needed to operate at a high frequency inorder to resolve targets, but the upper frequency was limited,because transmitters at that time had insufficient power. Theavailable frequencies required huge antennas that could not bemoved. Britain developed the bistatic Chain Home (CH) radarfor air defense in the late 1930s [13]. The 23.1-MHz transmit

Figure 1. Braun’s three-element array [5].

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array had towers that were about 107 m tall and spaced about55 m apart (see Figure 4). These towers held eight horizontaldipoles for the main array and a four-dipole array that coveredlow angles for close targets. In April 1937, CH was able todetect aircraft at a distance of 160 km. Wooden towers for thereceiving arrays were about 76 m tall and initially had threereceiving antennas in the form of two dipoles arranged in across configuration.

As the war progressed in Europe, better radars were needed.A new US-developed long-range radar called the SCR-270(Figure 5) was available in Hawaii and detected the Japanese for-mation attacking Pearl Harbor. Unlike CH, it could be mechani-cally rotated in azimuth 360� in order to steer the beam andoperated at a much higher frequency. The SCR-270 had four rowsof eight horizontal dipoles and operates at 110 MHz [15]. Thisfrequency is much higher than CH and allowed for much highergain and resolution for detecting aircraft as well as the ability tomechanically rotate the much smaller higher frequency antenna.

In 1942, Bell Labs built the X-band Mark 8 surface firecontrol radar that had an array of 14 � 3 polyrod antennas(see Figure 6) [16]. It used mechanically switched rotaryphase shifters attached to the columns for azimuth scanning.This was the first use of the polyrod antenna in an array andthe first microwave phased array.

Schelkunoff developed a general approach to the analysisand synthesis of linear arrays in 1943 [18]. His array polynomialand associated unit circle forms the basis of array analysis andsynthesis in the years to come.

In 1944, the Germans built the Mammut 1 radar to detectaircraft. The 10 m � 25 m eight-element array (see Figure 7)scanned �50� in azimuth using helical phase shifters [19]. Inthe same year, Dr. Hans Rindfleisch of Germany built the firstWullenweber array in Skisby, Denmark [20]. It had 40 verti-cal radiator elements, placed on a 120-m-diameter circle with40 reflecting elements installed behind the radiator elements

Figure 2. Four-element direction-finding array from Adcock’spatent [6].

Figure 3. MUSA, a six-element rhombic array, with one ofthe phase-shifting condensers in the lower left [10] Ó1937.

Figure 4. CH array [14] (imperial war museums non-commercial license).

Figure 5. SCR-270 antenna array (photo taken by R. Hauptat the National Electronics Museum).

Figure 6. Mark 8 planar phased array with polyrod elements[17] Ó2010 (courtesy of National Electronics Museum).

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around a circle having a diameter of 112.5 m (see Figure 8).Wullenwever was the WWII German cover name for the an-tenna: The Germans actually called it Wullenwever. Americanscould not pronounce it, so they changed the name. After thewar, the Soviets built many of these arrays and even trackedSputnik with them. The United States got interested later andended up building many of them for the US Navy. An examplecan be seen on Google Maps by entering the coordinates 48.951,�54.525 for Gander, Newfoundland, Canada.

Louis Alvarez developed a waveguide-fed linear dipolearray for three radar applications at the MIT Radiation Labfrom 1940 to 1943: 1) ground-controlled approach; 2) micro-wave early warning; and 3) Eagle precision bombing [22]. Thefirst two were ground based, so the array fed a parabolic re-flector to increase the gain. Alvarez wanted to use a slottedwaveguide, but his idea was discarded due to the difficulty ofmachining the slots. Instead, dipoles were placed at equallyspaced holes in the waveguide. The fields were coupled usingprobes. Placing the holes so that the elements were fed in phaseresulted in unacceptable grating lobes due to the large elementspacing. Alvarez cleverly halved the element spacing, so thesignals at adjacent elements were 180� out of phase. He thentwisted the probes of every other dipole by 180�, so all the el-ements have the same phase. No wonder he won the NobelPrize! Beam scanning resulted from changing the frequency.The resonant frequency of the waveguide was changed by in-creasing/decreasing the width of the waveguide.

4. Arrays in the Computer Age: 1946–1964

After the war, Dolph published his important paper oncontrolling the sidelobes/beamwidth of an array by amplitudetapering [23]. He mapped the array factor of a linear array to

a Chebyshev polynomial in order to get peak sidelobe levelsthat were equal and at a specified level below the peak of themain beam. A few years later, Taylor developed sidelobe ta-pers with predetermined sidelobes for linear [24] and circularplanar arrays [25].

In the mid 1950s, digital computers became powerful en-ough to control a phased-array radar and analyze the returns.In the late 1950s, Hughes Aircraft Company developed a de-sign for a planar array that scans in azimuth and elevation [26].Their resulting design had two stationary planar arrays on eachof the four sides of a ship’s superstructure (see Figure 9) [27].The first radar (AN/SPS-32) was a 2-D long-range air searchradar that displayed the location of airplanes on a scope read bya radar operator. The operator fed these targets to a computerthat controlled the beam of a 3-D search radar (AN/SPS-33)that was frequency scanned in elevation and phase scanned inbearing. The two arrays were called billboard radars due tothe large size of the arrays (250 � 200 and 400 � 200).

In late 1956, GE’s Advanced Electronics Center inventedthe sidelobe canceler [28]. They transmitted a strong jammingsignal in the direction of a sidelobe of the large main antennaA small auxiliary omniantenna with a gain about the same asthe gain of the main antenna sidelobes sat beside and pointedin the same direction as the main antenna. At video frequen-cies, they subtracted the output of the omniantenna from thejamming in the main antenna using automatic gain control tominimize the canceled residue. Since the auxiliary gain was about30 dB less than the main lobe gain of the main antenna, thedesired target signal was not canceled. Howells and Applebaumrecognized the potential of this technique if it could be made towork at RF frequencies. They invented the correlation loop andapplied it to antenna arrays. This was the first adaptive antennaand used the Howells–Applebaum adaptive loop. These resultswere not published until the 1970s. Later in the 1960s, Widrowdeveloped a very similar approach using the least mean squares(LMS) algorithm [29]. The two approaches differ in that theHowells–Applebaum algorithm needs to know the beam steer-ing vector, whereas the LMS algorithm needs a facsimile of thereceived signal. Consequently, the Howells–Applebaum approach

Figure 8. Wullenweber array in Skisby, Denmark [21].Figure 9. Long Beach launched in 1961 with the AN/SPS-32and AN/SPS-33 radar antennas (courtesy of US Navy).

Figure 7. Mammut 1 array (courtesy of U.S. National Archivesand Records Administration).

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works best for radar, whereas the LMS approach works bestfor communications systems.

In the 1950s, lens antennas became popular for applicationsrequiring multiple beams. The antenna for the Nike AJAX MPA-4radar was a zoned waveguide lens (see Figure 10) [30]. This wasthe first implementation of monopulse. In 1963, the Rotmanlens [31] debuted. It is a type of bootlace lens with three focal

points that forms simultaneous multiple beams (see Figure 11).The Butler matrix is a hardware version of the fast Fouriertransform that has 2M inputs and 2M orthogonal beams [32].

A very important development in 1960 was the Wilkinsonpower divider/combiner (see Figure 12) [33]. These combiners/dividers are widely used in arrays, because they are reciprocal,have all ports matched, and have good isolation between ports.

The following year, Sharp found that triangular spacingin a planar array (see Figure 13) not only delays the appear-ance of grating lobes but allows larger elements in the array[34]. An array with triangular spacing has 86.6% fewer ele-ments than the same-sized array with a square lattice.

5. Solid-State Arrays: 1964–Present

The development of semiconductor electronics in the 1960shad a huge impact on phased-array technology. The MolecularElectronics for Radar Applications (MERA) Program launchedthe development of the monolithic microwave integrated circuit(MMIC) T/R module in 1964 [35]. The module was fabricatedon high-density alumina and high-resistivity silicon, using thin-film techniques (see Figure 14). Circuits are located on bothsides of the module. Each module in the array transmitted apeak power of 0.6 W at 9.0 GHz and had a four-bit phaseshifter. The module was 7.1 � 2.5 � 0.8 cm, and it weighed27 g. During this same period, the AN/FPS-85 UHF (450 MHz)radar (see Figure 15) was built to detect space objects [36].Separate transmit and receive arrays were built rather than usediplexers and a single aperture. A unique idea for this arraywas to place vacuum tube transmitters at each element ratherthan use one large source and a dividing network. An engineernoticed that the radiating elements looked like a toilet bowlfloat, and subsequently, significant savings resulted by hiringa toilet bowl manufacturer to build the elements! Constructionended in 1965, but it burned down because the transmitter powerignited the plastic insulation in the coaxial cables. The prefireradar used analog phase shifters and vacuum tube receivers.The postfire radar used diode phase shifters and transistorreceiversVquite a change in a short time!

In 1969, the AN/APQ-140 radar used the Reflected ArrayRadio Frequency (RARF) manufactured by Raytheon [37].

Figure 10. Nike AJAX MPA-4 zoned waveguide lens (Phototaken by R. Haupt at the National Electronics Museum).

Figure 11. Original Rotman lens concept [31] Ó1963.

Figure 12. Wilkinson power divider/combiner [33] Ó1960.

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Figure 16 shows the reflectarray surface with 3500 passive phase-shifting modules that scan �60� in elevation and azimuth. Thisarray replaced the reflector antenna in the nose of airplanes.

In the 1970s, two very important array elements openedup many new avenues for phased arrays. The microstrip patchwas a narrowband element first proposed by Deschamps in 1953[38]. The patch did not revolutionize array design until Munsonfigured out how to make practical use of them in 1972 [39].

Figure 13. Example of triangular spacing [17] Ó2010 (courtesyof Ball Aerospace & Technologies Corporation).

Figure 14. MERA array with module and close-up of elements[17] Ó2010 (courtesy of National Electronics Museum).

Figure 15. AN/FPS-85 UHF (450 MHz) radar (courtesy ofUSAF).

Figure 16. RARF [17] Ó2010 (courtesy of National Elec-tronics Museum).

Figure 17. Large planar microstrip arrays can be madefrom self-similar parts [17] Ó2010.

Figure 18. Conformal Airlink antenna for satellite com-munications from an airplane [17] Ó2010 (courtesy of BallAerospace & Technologies Corporation).

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Patches are very thin and readily conform to a curved surface.In addition, the patches can be mass produced using relativelycheap circuit board technology, and large arrays can be as-sembled (see Figure 17). Patches inspired the idea of makingarrays conform to the shape of a curved surface rather thanbeing limited to a planar surface. AIRLINK is an airborne sat-ellite conformal array system (Figure 18) for in-flight telephone,fax, and data transmission that operates at 1530–1559 MHz onreceive and 1626.5–1660.5 MHz on transmit. This conformalmicrostrip antenna array is thin and is a panel on the body ofan airplane. The second important array element is the taperedslot antenna or Vivaldi antenna [40]. It is a flared slot line thatis a very broad band and has a fairly constant beamwidth overthe bandwidth (see Figure 19).

The Airborne Warning and Control System (AWACS)S-band planar array appeared on the scene in 1976 with 4000slots (see Figure 20) [41]. This array rotates in azimuth and is

Figure 19. First Vivaldi antenna and array [40] Ó1979.

Figure 20. AWACS array [17] Ó2010 (courtesy of USAF and NationalElectronics Museum).

Figure 21. EAR [17] Ó2010 (courtesy of National Elec-tronics Museum).

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electronically scanned in elevation using 28 ferrite phase shifters.The amazing achievement of the designers is the sidelobelevel: average sidelobe level was �45 dB (bottom of Figure 20).

Electronically Agile Radar (EAR) was developed in the1970s for airborne radar systems. It had 1818 circular wave-guide elements connected to phase shifters that scanned thebeam (see Figure 21). Moreover, in the 1970s, Raytheon built aseries of very large phased arrays for tracking missiles. The firstwas the AN/FPS-108 COBRA DANE (see Figure 22). It

operates from 1215 to 1400 MHz and has a 29-m phased-arrayantenna with 136� azimuth coverage.

So far, we have only described how military needs havedriven the development of phased arrays. Radio astronomyhas pushed the frontiers of arrays as well. The very large array isa Y-shaped radio telescope that has 27, 25-m reflector antennas[43]. The elements can be configured in four ways with a maxi-mum width of 36 km. This array came online in 1980. It com-bines both large reflector antennas as elements with the arrayconcept in order to meet the huge resolution requirements inradio astronomy.

The AN/APG-77 Advanced Tactical Fighter (ATF) ra-dar used a GaAs MMIC T/R module. Its 1500 elements fit in-side the nose cone of a USAF F-22A [17]. The module inFigure 23 shows a dramatic increase in complexity from theMERA module in 1964 to this module in 1987.

The sea-based X-band (SBX) radar began operation in2006, having 22 000 T/R modules, radiates 12 MW, and tracksand identifies long-range missiles (see Figure 24) [44]. The radaris mounted on a modified, self-propelled, and semisubmersibleoil platform. Its 284 m2 active aperture covers 360� in azimuthand almost 90� in elevation.

6. Arrays of the Future

One of the holy grails of antenna arrays is digital beam-forming (DBF) [45]. DBF places analog-to-digital converters atthe elements of an array (Figure 25). Because the signals be-come computer data at the elements, all the beamforming isdone in software instead of hardware. As a result, adaptive nul-ling, generating multiple beams, lowering sidelobes, and manyother signal processing type techniques can be implemented. Thisapproach is very expensive and requires real-time calibration;hence, it has been limited to relatively small arrays. A transmit ap-proach starts with a signal generator that sends signals to each ele-ment through a digital-to-analog converter and transmitter.

Radio astronomy is pushing the state of the art of phasedarrays with the Atacama Large Millimeter/submillimeter Array(ALMA) [46]. It consists of 80 antennas in the Chilean Andes

Figure 22. Cobra Dane (courtesy of DefenseImagery.mil).

Figure 23. AN/APG-77 ATF radar [17] Ó2010 (courtesyof Northrop Grumman and available at the NationalElectronics Museum).

Figure 24. SBX radar [17] Ó2010 (Courtesy of Missile Defense AgencyHistory Office).

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at 5000 m above sea level [18]. This radio telescope has 6612- and 7-m parabolic dishes that operate from 31.25 to 950 GHz.Array configurations from 250 m to 15 km will be possible.The ALMA antennas are movable between prebuilt stationaryflat concrete slabs (see Figure 26), and the beams are formed inreal time using optical fiber feeds.

Although linear and planar array technology is well estab-lished, the need for conformal arrays pushes the boundaries ofarray technology. Spherical arrays are difficult to build but arefar superior to planar arrays for hemispherical coverage. Spheri-cal arrays have lower polarization, mismatch, and gain losseswith scan than planar arrays. Figure 27 shows a five-panel por-tion of a 10-m diameter spherical array approximated by flatpanels. The center pentagonal panel has ten hexagonal sub-arrays, whereas the surrounding five hexagonal panels have21 hexagonal subarrays [17].

One of the approaches to reducing the cost of phasedarrays is to place the entire array on a single multilayer cir-cuit board. Current technology allows planar arrays throughthe X-band. Figure 28 shows that typical components of anactive phased array easily fit within the unit cell at the X-band.The size of these components does not dramatically changewith frequency due to packaging, so they do not fit within theunit cell of the array at Ku, K, Ka, and Q bands (see Figure 28).Figure 29 is an example of an array with the elements on one

side of a multilayer printed circuit board (PCB) and the com-ponents on the other side. Affordable manufacturing of arrayson single PCBs is vital to their future.

Advances in semiconductor technology is critical tomaking T/R modules more efficient, smaller, and of higherpower. Gallium nitride is making important inroads into newT/R module technology. New ideas in cooling techniques areimportant for high-power transmit arrays. Current research inphased arrays also include topics such as broadband arrays,cheaper T/R modules, multiple-input–multiple-output arrays,terahertz arrays, reconfigurable arrays, distributed arrays, andmuch more. Large wide-scanning wide-bandwidth arrays re-quire time delay units, which means “phased arrays” become

Figure 25. Transmit and receive digital beamforming.

Figure 26. ALMA [47] Ó2013.

Figure 27. Portion of 10-m-diameter spherical array ap-proximated by planar subarrays [17] Ó2010 (courtesy ofBall Aerospace & Technologies Corporation).

Figure 28. Components (yellow square blocks) relative tothe unit cell (red solid square box) at different frequencybands. The components have the same size, but the unit celldecreases as the frequency increases.

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“timed arrays.” The demand for phased arrays will continue.Our challenge is to make them affordable.

7. Acknowledgement

The National Electronics Museum and Northrop Grummanas well as Ball Aerospace & Technologies were instrumentalin providing many of the pictures used in [17] and in this paper.If you like antenna arrays, please visit the National ElectronicsMuseum whenever you are in the vicinity of the BaltimoreairportVits free!

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[42] National Electronics Museum, “EAR Antenna,” 2009, Display Information.[43] National RadioAstronomy Observatory, “An Overview of the Very

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Figure 29. Front (antenna elements) and back (components) of a pla-nar antenna array Ó2010 (courtesy of Ball Aerospace & Technolo-gies Corporation).

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Randy L. Haupt received the B.S.E.E. degreefrom the United States Air Force Academy(USAF Academy), Colorado Springs, CO, USA,in 1978; the M.S. degree in engineering man-agement from Western New England College,Springfield, MA, USA, in 1982; the M.S.E.E.degree from Northeastern University, Boston,MA, in 1983; and the Ph.D. degree in electricalengineering from The University of Michigan,Ann Arbor, MI, USA, in 1987.

He is a Professor and the Head of the Depart-ment of Electrical Engineering and ComputerScience, Colorado School of Mines, Golden,

CO. He was an RF Staff Consultant with Ball Aerospace & Technologies Cor-poration; a Senior Scientist and the Department Head with the PennsylvaniaState University Applied Research Laboratory, College Park, PA, USA; a Pro-fessor and the Department Head of Electrical and Computer Engineering withUtah State University, Logan, UT, USA; a Professor and Chair of ElectricalEngineering with the University of Nevada Reno, Reno, NV, USA; and a Pro-fessor of electrical engineering with the USAF Academy. He was a Project Engi-neer for the OTH-B radar and a Research Antenna Engineer for the Rome AirDevelopment Center early in his career. He is a coauthor of the books PracticalGenetic Algorithms (2nd edition, John Wiley & Sons, 2004), Genetic Algo-rithms in Electromagnetics (John Wiley & Sons, 2007), and Introduction toAdaptive Antennas (SciTech, 2010) and an author of Antenna Arrays a Compu-tation Approach (John Wiley & Sons, 2010) and Timed Arrays (John Wiley &Sons, 2015).

Dr. Haupt is a Fellow of the IEEE and Applied Computational Electromag-netics Society.

Yahya Rahmat-Samii (S’73–M’75–SM’79–F’85) is a Distinguished Professor, holderof the Northrop Grumman Chair in Electro-magnetics, and past Chairman of the Elec-trical Engineering Department, Universityof California, Los Angeles (UCLA), LosAngeles, CA, USA. He was a Senior ResearchScientist with the National Aeronautics andSpace Administration (NASA) Jet PropulsionLaboratory (JPL), California Institute of Tech-nology, Pasadena, CA, prior to joining UCLAin 1989. In the summer of 1986, he was aGuest Professor with the Technical University

of Denmark, Copenhagen, Denmark. He has also been a consultant to numer-ous aerospace and wireless companies. He has been an Editor and a Guest Edi-tor of numerous technical journals and books. He has authored and coauthoredover 950 technical journal and conference papers and has written 35 bookchapters. He is a coauthor of “Electromagnetic Band Gap Structures in AntennaEngineering” (New York: Cambridge, 2009), “Implanted Antennas in MedicalWireless Communications” (Morgan & Claypool Publishers, 2006), “Elec-tromagnetic Optimization by Genetic Algorithms” (New York: Wiley, 1999),and “Impedance Boundary Conditions in Electromagnetics” (New York: Taylor& Francis, 1995). He has received several patents. He has had pioneering researchcontributions in diverse areas of electromagnetics, antennas, measurement anddiagnostics techniques, numerical and asymptotic methods, satellite and per-sonal communications, human/antenna interactions, radio frequency identifica-tion and implanted antennas in medical applications, frequency-selectivesurfaces, electromagnetic bandgap structures, applications of the genetic algo-rithms, and particle swarm optimization (http://www. antlab.ee.ucla.edu/).

Dr. Rahmat-Samii is a member of the US National Academy of Engineering(NAE) and a winner of the 2011 IEEE Electromagnetics Award. He is a Fellowof the Institute of Advances in Engineering and a member of Commissions A,B, J, and K of USNC-URSI, the Antenna Measurement Techniques Association(AMTA), Sigma Xi, Eta Kappa Nu, and the Electromagnetics Academy. Hewas the Vice President and President of the IEEE Antennas and PropagationSociety in 1994 and 1995, respectively. He was appointed an IEEE AP-S Dis-tinguished Lecturer and presented lectures internationally. He was a member ofthe Strategic Planning and Review Committee of the IEEE. He was the IEEEAP-S Los Angeles Chapter Chairman (1987–1989); his Chapter won the BestChapter Award in two consecutive years. He is listed in Who’s Who in America,Who’s Who in Frontiers of Science and Technology, and Who’s Who in Engi-neering. He has been the plenary and millennium session speaker at numerousnational and international symposia. He has been the organizer and presenter ofmany successful short courses worldwide. He was the Director and Vice Presi-dent of AMTA for three years. He has been a Chairman and Cochairman of

several national and international symposia. He was a member of the UCLAGraduate council for three years. He was the Chair of USNC-URSI during2009–2011. For his contributions, he has received numerous NASA and JPLCertificates of Recognition. In 1984, he received the Henry Booker Award fromURSI, which is given triennially to the most outstanding young radio scientistin North America. Since 1987, he has been designated every three years as oneof the Academy of Science’s Research Council Representatives to the URSIGeneral Assemblies held in various parts of the world. He was also an invitedspeaker to address the URSI 75th anniversary in Belgium. In 1992 and 1995, hereceived the Best Application Paper Prize Award (Wheeler Award) for paperspublished in 1991 and 1993 IEEE TRANSACTIONS ON ANTENNAS AND PROPA-GATION. In 1999, he received the University of Illinois ECE DistinguishedAlumni Award. In 2000, he received the IEEE Third Millennium Medal and theAMTA Distinguished Achievement Award. In 2001, he received an HonoraryDoctorate in applied physics from the University of Santiago de Compostela,Santiago de Compostela, Spain. In 2001, he became a Foreign Member of theRoyal Flemish Academy of Belgium for Science and the Arts. In 2002, he re-ceived the Technical Excellence Award from JPL. He received the 2005 URSIBooker Gold Medal presented at the URSI General Assembly. He was a recipi-ent of the 2007 Chen-To Tai Distinguished Educator Award of the IEEE Anten-nas and Propagation Society. In 2008, he was elected to membership in the USNAE. In 2009, he was selected to receive the IEEE Antennas and PropagationSociety highest award, Distinguished Achievement Award, for his outstandingcareer contributions. He was a recipient of the 2010 UCLA School of Engineer-ing Lockheed Martin Excellence in Teaching Award and the 2011 UCLA Dis-tinguished Teaching Award. In 2012, he was elected as a Fellow of the AppliedComputational Electromagnetics Society. He is the designer of the IEEE AP-Slogo, which is displayed on all IEEE AP-S publications.

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