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nas) and Globalstar MMIC space-borne active array systems (these last two are for communi- cations, but the technology is the same as used by radar systems. In fact, the IRIDIUM T/R module technology derives from technology developed for a space-based radar); Thales (formerly Thomson-CSF) 4" MMIC wafer, 94 GHz seeker antenna; digital beamforming; ferroelectric row-column scanning; optical electronic scanning for communications and radar; the MMIC C- to Ku-band advanced shared aperture program (ASAP) and AMRFS antenna systems for shared use for communi- cations, radar, electronics countermeasures (ECM) and electronic support measures (ESM); and the continuous transverse stub (CTS) voltage-variable dielectric (VVD) antenna. ACCOMPLISHMENTS OVER THE LAST TWO AND A HALF DECADES Phased arrays have come a long way in the last three decades. This is illustrated by the many tube passive arrays and solid-state active arrays, which use discrete and MMIC tech- nologies that have been deployed or are under development. 1–24,82–84,86 Figures 1 and ELI BROOKNER Raytheon Co. Sudbury, MA T his is a survey article summarizing the recent developments and future trends in passive, active, bipolar and monolith- ic microwave integrated circuitry (MMIC) phased arrays for ground, ship, air and space applications. Covered is the DD(X) ship radar suite; THAAD (formerly GBR); European COBRA; Israel BMD radar antennas; Dutch shipboard APAR; airborne US F-22, JSF and F-18 radars, European AMSAR, Swedish AESA, Japan FSX and Israel Phalcon; Iridium (66 satellites in orbit for a total of 198 anten- PHASED ARRAYS AND RADARS P AST , PRESENT AND FUTURE Fig. 1 Examples of US passive phased arrays having large productions. Reprinted with permission of MICROWAVE JOURNAL ® from the January 2006 issue. © 2006 Horizon House Publications, Inc.
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Page 1: ROOKNER - messagedata.eefocus.com/myspace/5/27680/bbs/1199754328/...for MMIC active phased array con-tracts, such as for three THAAD EDM (engineering development model) radars, COBRA

nas) and Globalstar MMIC space-borne activearray systems (these last two are for communi-cations, but the technology is the same as usedby radar systems. In fact, the IRIDIUM T/Rmodule technology derives from technologydeveloped for a space-based radar); Thales(formerly Thomson-CSF) 4" MMIC wafer, 94GHz seeker antenna; digital beamforming;ferroelectric row-column scanning; opticalelectronic scanning for communications andradar; the MMIC C- to Ku-band advancedshared aperture program (ASAP) and AMRFSantenna systems for shared use for communi-cations, radar, electronics countermeasures(ECM) and electronic support measures(ESM); and the continuous transverse stub(CTS) voltage-variable dielectric (VVD)antenna.

ACCOMPLISHMENTS OVER THE LASTTWO AND A HALF DECADES

Phased arrays have come a long way in thelast three decades. This is illustrated by themany tube passive arrays and solid-state activearrays, which use discrete and MMIC tech-nologies that have been deployed or are underdevelopment.1–24,82–84,86 Figures 1 and

ELI BROOKNERRaytheon Co.Sudbury, MA

This is a survey article summarizing therecent developments and future trendsin passive, active, bipolar and monolith-

ic microwave integrated circuitry (MMIC)phased arrays for ground, ship, air and spaceapplications. Covered is the DD(X) ship radarsuite; THAAD (formerly GBR); EuropeanCOBRA; Israel BMD radar antennas; Dutchshipboard APAR; airborne US F-22, JSF andF-18 radars, European AMSAR, SwedishAESA, Japan FSX and Israel Phalcon; Iridium(66 satellites in orbit for a total of 198 anten-

PHASED ARRAYSAND RADARS — PAST, PRESENT AND FUTURE

Fig. 1 Examples of USpassive phased arrays havinglarge productions. ▼

Reprinted with permission of MICROWAVE JOURNAL® from the January 2006 issue.©2006 Horizon House Publications, Inc.

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2 show passive phased arrays, thefirst generation of phased arrays. Fig-ure 3 shows Rotman lens arrays. Fig-ure 4 shows active solid-state arraysusing discrete components, the sec-ond generation. Figures 5 and 6 arefor phased arrays using microwaveanalog integrated circuits (MMIC),the third generation. The numbersmanufactured are shown in parenthe-ses in the figures. Note that in somecases, very large numbers have beenproduced, even for MMIC activephased arrays (see Table 1). Also,one sees that phased arrays are beingdeveloped around the world. Includ-ed are the new L-band GEC-Mar-

coni S185OM (SMARTELLO),which will provide very long rangesearch for the SAMPSON radar onthe Royal Navy Type 45 anti-air war-fare (AAW) destroyer and the newAMS L-band RAT 31DL.86 TheSMARTELLO uses the SMART-Lantenna and elements of the Martel-lo. The Iridium satellite system hasbeen deployed; it consists of a con-stellation of 66 satellites. It was agreat technological success but unfor-tunately not a financial one.14 It isstill in operation, however. In fact,three replacement satellites werelaunched in 2002. Figure 7 showsadditional phased arrays that have re-cently come under development, forwhich the technology is not specified.Included are the US Army’s joint landattack cruise missile defense elevatednetted sensors system (JLENS), con-sisting of a long range 3-D surveil-lance radar and a high frequency pre-cision tracking and illumination radardeployed in an aerostat; the mediumextended air defense system(MEADS) UHF surveillance radar;the US Army’s multi-mission radar(MMR); UK/US airborne stand-offradar (ASTOR), the UK equivalent ofthe US joint STARS (JSTARS), andthe US Marine Corps affordableground-based radar (AGBR) andmultiple role radar system (MRRS).Figures 8 and 9 give the state-of-the-art of GaAs MMIC power ampli-fiers and of GaAs and InP low noiseamplifiers (LNA).85 The People’s Re-public of China has come a long wayin a very short time in the develop-

ment of phased arrays — passive, ac-tive, over-the-horizon, dual-band,wide-band, ultra-low sidelobe, syn-thetic-aperture, adaptive, digital-beamforming, super-resolution andphase only null steering.76 The ques-tion addressed now is what does thefuture hold?

DEVELOPMENT OF MMIC ACTIVEPHASED ARRAYS

With the recent awards of pro-duction and development contractsfor MMIC active phased array con-tracts, such as for three THAADEDM (engineering developmentmodel) radars, COBRA radars,SAMPSON radars, sea-based testXBR radars, forward-based BMDsradars, MEADS radars, air trafficnavigation, integration and coordina-tion system (ATNAVICS) radars,four-faced active phased-array radar(APAR) system, the new B-2 radar,multi-platform radar technology in-sertion program (MP-RTIP) on E-10A (upgrade of the Joint STARS),MP-RTP on Global Hawk, F-15C(AN/APG-63(V), 25 already in serv-ice), F-16, F/A-18, F/A-22 and F-35joint strike fighter (JSF) airborneradars, the planned developmentcontracts for the new US DD(X)ship and SPY-3/VSR radar suite, thefuture looks very good for MMICradars.79,80,83 The new X-band SPY-3under development for the DD(X)ship, the US Navy’s first active radar,is planned to be used for the detec-tion, tracking and illumination of lowflying, anti-ship, cruise missiles and

COVER FEATURE

▲ Fig. 2 Examples of passive phased arrays from around the world.

▲ Fig. 3 Examples of ROTMAN lensarrays.

▲ Fig. 4 Examples of active arrays using discrete components.

SMARTELLO (2)

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is expected to consist of a three-faced radar.83 When not supportingengagement operations, it will per-form horizon search, surface searchand periscope detection.83 The co-operative engagement capability(CEC) is a Navy ship and communi-cations array antenna. Figures 10and 11 show space-based radar anddigital beamforming phased-arraysystems that have been deployed orare under development.

RESEARCH AND DEVELOPMENTWORK FOR FUTURE PHASED-ARRAY SYSTEMSClutter Rejection for an AirborneSystem (STAP and DPCA)

To cope with ground clutter andsidelobe jamming for airborneradar, extensive work is ongoingtoward the development of anairborne phased array using space-t ime adaptive processing(STAP).25,26 STAP is a general formof displaced phase center antenna(DPCA) processing. STAP had beendemonstrated several years ago on amodified E2-C system by NRL.27,28

More recently, a flight demonstra-tion STAP provided 52 to 69 dB ofsidelobe clutter cancellation rela-tive to the main beam clutter.29

This system used an array mountedon the side of an aircraft. The an-tenna had 11 degrees of freedom inazimuth and two in elevation, for atotal of 22. Before STAP, the anten-na RMS sidelobe level was -30 dBi;with STAP, it was –45 dBi.

C- to Ku-band Multi-user AdvancedShared Aperture Program (ASAP)MMIC Array and Dual-band AMRFSand RECAP Arrays

The COBRA DANE radar systemhas a 16 percent bandwidth and theRotman lens multi-beam array sys-tems have a 2.5 to 1 frequency band-

width. Technology had been carriedout to develop an active MMICphase-phase steered array that has agreater than 2 to 1 frequency band-width and at the same time is sharedby multiple users. Specifically, theNaval Air Weapons Center (NAWC)and Texas Instruments (TI, now partof Raytheon) were developing abroadband array having continuouscoverage from C- through Ku-bandthat would share the functions ofradar, passive electronic support mea-sures (ESM), active electroniccounter measures (ECM) and com-munications.30 To achieve this widebandwidth, a flared notch-radiatingelement was used. Cross notcheswere used so that horizontal, verticalor circular polarization could be ob-tained. They built a solid-state T/Rmodule that provides coverage overthis wide band from C- to Ku-bandcontinuously. The module had a pow-er output of 2 to 4 W per element, anoise figure between 6.5 and 9 dB,and power efficiency between 5.5and 10 percent, over the band. A 10by 10-element array, having eight ac-tive T/R modules, was built for testpurposes. A typical full-up arraywould be approximately 29" wide by13" high. With this type of array, itwould be ultimately possible to usesimultaneously part of the array asradar, part of the array for ESM, partfor ECM and part for communica-tions. The parts used for each func-tion would change dynamically, de-pending on the need. Also, theseparts could be non-overlapping oroverlapping, depending on the needs.Although the ASAP funding has end-ed, the shared aperture technology isnow being pushed forward by the USOffice of Naval Research (ONR) ad-vanced multifunction radar frequencysystem (AMRFS) program71,78 andthe DARPA reconfigurable aperture

program [RECAP] program. DERAof the UK had been developing adual frequency array which would en-able a single radar to use L-band forsearch and X-band for track, so as toavoid the use of a single compromisefrequency for search and track.52

Consideration is being given to the

COVER FEATURE

▲ Fig. 5 Examples of ground and shipboard MMIC active arrays deployed and under development.

▲ Fig. 6 Examples of airborne MMICactive arrays deployed and underdevelopment.

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use of waveguide L-band radiating el-ements and dipole X-band elements.

Digital Beamforming and Its Potential

Table 2 lists where digital beam-forming (DBF) has been operationallyused, some developmental systems thathave been built, and its significant ad-vantages. The first operational radars touse digital beamforming are the over-the-horizon (OTH) radars, specificallythe GE OTH-B and Raytheon relocat-able OTH radar (ROTHR). TheROTHR receive antenna is approxi-

mately 8500 feet long. More recently,Signaal used digital beamforming fortheir deployed 3-D stacked beamSMART-L and SMART-S shipboardsystems. Each row is down convertedand pulse compressed with SAW linesand then analog-to-digital (A/D) con-verted with 12-bit, 20 MHz Analog De-vices A/Ds. The signal is then modulat-ed onto an optical signal and passeddown through a fiber optic rotary jointto a digital beamformer where 14beams are formed.31

A number of experimental DBFsystems have been developed. One is

the Rome Laboratory (HanscomAFB, MA), 32 column linear array atC-band that can form 32 indepen-dent beams and uses a novel self-cali-bration system.32 Rome Laboratorieshas also developed a fast digitalbeamformer that utilizes a systolicprocessor architecture77 based on thequadratic residue number system

COVER FEATURE

TABLE IEXAMPLES OF RADAR PHASED ARRAYS HAVING LARGE PRODUCTIONS

Total NumberSystem Frequency Number Number of Phase of Elements ManufacturerBand Manufactured Shifters/Array Manufactured

AN/TPN-25 X 18 824 14,850 Raytheon

AN/GPN-22 X 60 443 26,580 Raytheon

COBRA DANE L 1 15,360 (34,769 Els.) 15,360 (34,769 Els.) Raytheon

PAVE PAWS UHF 4 1,792/face (2,677 Els.) 14,336 (21,416 Els.) Raytheon

BMEWS UPGRADE UHF 2 2,560/face (3,584 Els./face) 12,800 (17,920 Els.) Raytheon

COBRA JUDY – 1 12,288 12,288 Raytheon

PATRIOT C 173 5,000 1,730,000 Raytheon

AEGIS (SPY-1) S 234 4,000 936,000 Lockheed-Martin

B-1 X 100 1,526 152,600 Northrop Grumman

AN/TPQ-37 S 102 359 36,618 Raytheon

AN/TPQ-36 X 243 Raytheon

FLAP LID X > 100 (?) 10,000 > 2 million (?) Russia

▲ Fig. 7 Other phased-array systems under development.

PO

WER

(W

)

EFFICIEN

CY (%

)

FREQUENCY (GHz)

100

10

1

0.1

0.01

75

60

45

30

15

01 10 100 1000

▲ Fig. 8 State-of-the-art of GaAs MMICPAs.

NO

ISE

FIG

UR

E (d

B)

GA

IN (dB

)

FREQUENCY (GHz)

8

7

6

5

4

3

2

1

0

32

28

24

20

16

12

8

4

010 30 50 70 90 110

▲ Fig. 9 State-of-the-art of GaAs and InPMMIC LNAs.

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(QRNS).32 MICOM (US Army) builta 64-element feed that used DBF fora space-fed lens.33 The experimentalBritish MESAR S-band system doesdigital beamforming at the sub-arraylevel.34 This experimental system has16 sub-arrays and a total of 918 wave-guide-radiating elements and 156T/R solid-state modules. Roke ManorResearch Ltd. of Britain has built anexperimental 13-element array usingdigital beamforming on transmit as

well as on receive.35 This experimen-tal system uses the Plessey SP2002chip running at a 400 MHz rate as adigital waveform generator at everyelement. Doing digital beamformingon transmit allows one to put nulls inthe direction of an ARM threat orwhere there is high clutter.

The National Defense ResearchEstablishment of Sweden has built anexperimental S-band antenna operat-ing between 2.8 and 3.3 GHz, whichdoes digital beamforming using asampling rate of 25.8 MHz on a 19.35MHz IF signal.23 The advantage ofusing IF frequency sampling ratherthan base band sampling is that onedoes not have to worry about the im-balance between the two I and Qchannels, or the DC offset. Theydemonstrated that, by using digitalbeamforming, they could compensatefor amplitude and phase variationsthat occur from element to element,across angle and across the frequencyband. Via a calibration, they wereable to reduce an element-to-elementgain variation over angle, due to mu-tual coupling, from ±1 dB to approxi-mately ±0.1 dB. Using equalization,they were also able to reduce a ±0.5dB variation in the gain over the 5MHz bandwidth to less than ±0.05dB. With this calibration and equal-ization, they were able to demon-strate peak sidelobes 47 dB down,over a 5 MHz bandwidth. A 50 dBChebyshev weighting was used. TheRMS of the error sidelobes was down65 dB from the peak near bore-sight.63 They demonstrated that thecalibration was maintained fairly wellover a period of two weeks. This workdemonstrates the potential advantageoffered by digital beamforming withrespect to obtaining ultra-low anten-na sidelobes. These results were notachieved in real time in the field, al-though that is ultimately the goal.

MIT Lincoln Laboratory devel-oped the technology for an all-digitalradar receiver for airborne surveil-lance array radar like that of theUHF E-2C.43 They are A/D samplingdirectly at UHF (~430 MHz) using aRockwell 8-bit, 3 Gbps A/D runningat room temperature. Three stages ofdown conversion are done digitallyand because the A/D quantizationnoise is filtered, the effective numberof bits of the A/D is increased. Forexample, if the signal bandwidth isonly 5 MHz, the increase in signal-to-noise ratio is 3 GHz/2 (5 MHz) = 25dB, so the increase in the number ofeffective bits is 25 dB divided by 6dB/bit or 4.2 bits to yield 12 bits total.The whole digital receiver is on an 8"by 8" card that uses three 0.6 µmchips. In the future these three chipscould be replaced by a single 0.35 µmCMOS chip.

The Naval Research Laboratory(NRL), MIT Lincoln Laboratory andNSWC are jointly developing an L-band active array which has an A/Dconverter at every element.64,65,81

Using digital beamforming, NRLdemonstrated the ability to obtain aconstrained beamwidth with frequen-cy, while at the same time achievinglow sidelobes over specified anglesand frequency bands.66

MIT Lincoln Laboratory had beendeveloping a high performance, lowpower signal processor to do digitalbeamforming and signal processing fora notional X-band Discoverer II space-based radar.67,68 This notional versionof the system did ground moving targetindication (GMTI) and synthetic aper-ture radar (SAR) mapping. Its antennaconsisted of 12 sub-arrays and 4 SLCs.The signal bandwidth was assumed tobe 180 MHz. For this system, it is nec-essary to do the signal processing on-board and in real time, because teleme-tering the signal down would require

COVER FEATURE

▲ Fig. 10 Space-based phased-array systems.

▲ Fig. 11 Phased arrays that use digitalbeamforming.

UK

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too high a data rate –35 Gbps, if a 12-bit A/D is assumed —well beyond the present state-of-the-art. The on-board signalprocessor must do digital beamforming, pulse compression,Doppler processing, STAP and SLC. To do this on-boardand in real time requires a signal processor capable of 1100GOPS (1.1 TERAOP). Lincoln Laboratory has shown that itis feasible to do the processing on board using a systolic arraytype architecture having a volume less than one seventh of acubic foot, and weighing less than 13 kg with a power con-sumption less than 55 W. With the digital processing fieldbeing moved forward rapidly by the commercial world, bythe year 2016 it is expected that one 9U 16" by 14.5" boardwould provide a throughput of 600 GFLOPS (floating OPS).It would consist of 64 chips, each providing 10 GFLOPS usea 0.07 µm technology and have a 1.25 GHz clock. Texas In-struments (TI) road map, for its TMS320 digital signalprocessor (DSP), indicates that by the year 2010 they expectto be able to do 3 trillion, 8-bit OPS (3 trillion instructionsper second or 3 TIPS), on a single TMS320 chip.69 With 32-bit fixed-point operations, this chip would do 0.75 TIPS. As-

suming 10 percent efficiency, 15 chips would do the notionalDiscover II processing. Such processing capability couldhelp make the experimental Swedish ultra-low sidelobe an-tenna and airborne STAP array feasible.

Row-column Steered ArraysThe Naval Research Laboratory (NRL) had been de-

veloping two row-column array steering techniques,which have the potential for low cost two-dimensionalsteered arrays.36,37 The first technique, the one closest topossible deployment, involves using two arrays back-to-back. The first array steers the beam in azimuth, the sec-ond in elevation. The first array consists of columns ofslotted waveguides, with each column having at its inputone ferrite phase shifter to provide azimuth scanning. Thesecond array is a RADANT lens array, consisting of paral-lel horizontal conducting plates between which are con-nected many diodes. The velocity of propagation of theelectromagnetic signal passing through a pair of parallelplates of the array depends on the number of diodes thatare on or off in the direction of propagation. By appropri-ately varying this number, as one goes from one pair ofplates to the next in the vertical direction, one creates agradient on the signal leaving the lens in the vertical di-rection so as to steer the beam in elevation. The estimatedproduction cost of the hybrid row-column steered array is$3 million. It is possible to use two RADANT lenses toprovide two-dimensional electronic scanning, oneRADANT lens providing elevation scan while the secondprovides azimuth scan.38 Thales has developed such aRADANT antenna for the Dassault Aviation RAFALEmulti-role combat aircraft.38

The second NRL row-column steered array involves us-ing two ferroelectric lenses.37 The first lens consists ofcolumns of ferroelectric material placed between conductingplates. A DC voltage is applied across each pair of plates.The dielectric constant of the ferroelectric material dependson the DC voltage applied between the plates. As a resultthe phase of the electromagnetic signal passing through aferroelectric column will depend on this DC voltage. Conse-

COVER FEATURE

TABLE IIDIGITAL BEAMFORMING

Where Used: Advantages:

• OTH-B (GE): I-D • Flexibility

• ROTHR (Raytheon): I-D – Antenna Weighting• SMART-L and SMART-S (SIGNAAL): I-D Stacked Beam Systems – Growth with Technology

• Adaptive Processing

• Improved Performance

Developmental Systems: – Ultra-Low Sidelobes

• Rome Lab: 32 Columns – Dynamic Range

32 Independent Beams – Jammer and Clutter Suppression

• MICOM: Array Feed OF 64 Elements – Reduced EMI

• British MESAR: Subarray DBF • Multibeams

• British: DBF on Trans. and Rec. 13 EL

• Lincoln Lab. All-Digital UHF Receiver: 8 Bit 3 GSPS A/D

• AMSAR: Subarray DBF

RF Wavefrontin Antenna

for Scanned Beamin H-Plane

Phase-ShifterScanned

Beam(H-Plane)

Array ofPhase Shifters

H-Plane

E-Plane

RF in

Stubs PropagatingRF Wave

BoresightBeam

VoltageScanned

Beam(E-Plane)

scanφ

scanθ

V+

-

▲ Fig. 12 Low cost 2D electronically scanned antenna approachbased on two technologies: CTS antenna architecture and VVDmaterials.

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quently, by applying an appropriate DCvoltage across the ferroelectriccolumns, one can create a phase gradi-ent in the horizontal direction for thesignal leaving the first lens and thusscan the beam in azimuth. A secondsuch lens, rotated 90°, would steer thebeam in elevation. Considerable workis still necessary before a practical fer-roelectric phased array is produced.This work has been shifted from NRLto industry.

The Raytheon Co. is developing arow-column steered array that employsphase shifters for steering in the Hplane (see Figure 12) and a voltagevariable dielectric (VVD) ceramic ma-terial used for a continuous transversestub (CTS) antenna architecture forsteering in the E plane.41 Changing thevoltage across the VVD changes its di-electric constant and, in turn, the veloc-ity of propagation along the VVD. Itprovides for a lightweight, low cost,small thickness antenna. They are look-ing to apply this technology to aircraftradar antennas and commercial anten-nas. Engineers and scientists have beentalking about achieving electronic scan-ning of lasers since the 1960s. Somethought this was a pipe dream, butthese doubters have since been provenwrong. Raytheon40,57 has demonstratedan electronically steered phased arrayfor laser and optical beams. This array,which is carried around in a briefcase,represents a major breakthrough in thescanning of laser and optical beams.The scanning is achieved using a row-column scanning architecture similar tothat of the ferroelectric scanner previ-ously described, with liquid crystal usedinstead of the ferroelectric material. Inproduction, the cost per phase shifterfor an optical phased array is estimatedto be pennies.40,57

Novel Electronically SteerablePlasma Mirror

NRL had been pursuing the devel-opment of a novel electronically steer-able plasma mirror in order to provideelectronic beam steering.39 Here, aplasma sheet is rotated to steer thebeam in azimuth and is electronicallytilted to steer the beam in elevation.Switching to different initiation pointsin the cathode rotates the plasma mir-ror. Tilting the magnetic field aroundthe plasma tilts the plasma mirror. Thisis done using coils placed around theplasma. These coils are placed so as not

to block the microwave signal. A 50 by60 cm plasma mirror has been generat-ed, for which the measured antennapatterns had sidelobes approximately20 dB down.39

95 GHz Reflect-array Using 4"MMIC Wafers

Colin38 described a very aggressiveeffort wherein an MMIC was taken tothe point of wafer integration — 4"wafers. Specifically, Thales has built anexperimental missile seeker antenna,which uses two 4" wafers.38 One waferhas the dipole elements and one bitPIN diode phase shifters printed on it.The second 4" wafer contains the dri-ving circuits that are linked to the firstthrough bumps. The antenna has 3000elements. The beam width is 2° andcan be steered ±45°. They have report-ed having obtained low sidelobes.38

Micro-electro-mechanical System (MEMS) Components

The MEMS integrated circuit me-chanical switch holds the promise for a4-bit X-band phase shifter having lowloss (1.5 dB), low power consumption(1 mW) and low cost ($10 per phaseshifter).70 If such a phase shifter bearsfruit, it would be possible to revert backfor some applications to the passivephase-phase scanned array architecturehaving one power amplifier feedingmany low cost phase shifters. Instead ofa tube, the power amplifier could be asolid-state amplifier. This could reducethe number of T/R modules neededand hence the cost of a phase-phasescanned array by a considerableamount. The MEMS technology is be-ing funded by DARPA.70 They arelooking at using MEMS in their RE-CAP program to obtain reconfigurableultra-wideband antennas for multi-userapplications as done with the ASAPprogram described above.74,75

Low Cost Phase Array for theAutomobile

One tends to think of phased ar-rays as expensive. A low cost 77 GHzphased array has been developed forautomotive intelligent cruise controlradar, whose total consumer costneeds to be less than $300.72,73 Twoantennas, one for transmit and one forreceive, and their beamformer net-works are photo-etched on a singlesheet of copper clad dielectric. Theantennas consist of series fed columnsof patch radiators, while the beam-

formers are Rotman lens, one foreach array. The beams are scanned inazimuth by switching between inputports of the Rotman lens.

CONCLUSIONBased on the above accomplish-

ments, ongoing developments, re-search and large numbers of programsthat are looking to effectively usephased arrays, it is apparent that thefuture for phased arrays is verypromising and should lead to excitingdevelopments. Phased arrays havecome a long way and can be expectedto make major strides in the future.For further reading on recent devel-opments in phased arrays around theworld, the reader is referred to Refer-ences 1 to 14, 40, 46, 62, 82 and 83. ■

ACKNOWLEDGMENTThe author would like to thank

Doug Venture of the Raytheon Co.for his help.

REFERENCESDue to space limitations, the large

number of references used in this articlecan be found on the Microwave Journalweb site at www.mwjournal.com.

Eli Brookner has been atthe Raytheon Co. since1962, where he is aPrincipal Fellow. There hehas worked on the ASDE-X radar, ASTOR AirSurveillance Radar,RADARSAT II, AffordableGround Based Radar(AGBR), major SpaceBased Radar programs,NAVSPASUR S-bandupgrade, CJR, COBRA

DANE, PAVE PAWS, MSR, COBRA JUDY, THAAD,Brazilian SIVAM, SPY-3, AEGIS, BMEWS, UEWRand COBRA DANE Upgrade. Prior to Raytheon heworked on radar at the Columbia UniversityElectronics Research Lab [now RRI], Nicolet and theRome AF Lab. He was awarded the IEEE 2003Warren White Award for Excellence in RadarEngineering “For Significant Advances inDevelopment and Education of Phased ArrayRadars.” He is a Fellow of the IEEE, AIAA and MSS.He has published four books, the most recent beingTracking and Kalman Filtering Made Easy, JohnWiley & Sons Inc., 1998. His previous three bookswere Practical Phased Array Antenna Systems (1991),Aspects of Modern Radar (1988) and RadarTechnology (1977), all published by Artech HouseInc. He gives courses on radar, phased arrays andtracking around the world. He was banquet speakerand keynote speaker six times. He has over 110papers, talks and correspondences to his credit. Inaddition, he has over 80 invited talks and papers. Forone paper he has received the Journal of the FranklinInstitute Premium Award. For another he (along withhis co-authors) received the Wheeler Prize for BestApplications Paper for 1998. He received his BEEdegree from The City College of the City of New Yorkin 1953, and his MEE and DrSc degrees fromColumbia University in 1955 and 1962, respectively.

COVER FEATURE


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