Course Description

Course Name:	Phased-Array and Adaptive-Array Fundamentals and Their Amazing-Breakthroughs
Time & Date:	6 - 9 PM, Feb. 22, March 1, 8, 15, 22, 29, April 5, 12, 26, May 3(If needed snow/make-up days May 10, 17, 24)
Location:	MITRE Corporation, Bedford, MA
Speaker:	Dr. Eli Brookner, Raytheon Company

Course Summary:

1. Practical Phased Array Antenna Systems, Dr. Eli Brookner, Editor, Artech House, 1991, Hardcover, 258 pages, List Price $179. With the explicitly tutorial approach, This book is the course primary text. It offers a concise, introductory-level survey of the fundamentals without dwelling on extensive mathematical derivations or abstruse theory. Its presentation focuses on step-by-step design procedures and provides practical results using extensive curves, tables and illustrative examples.

2. Phased-Array Radar Design, T. W. Jeffrey, 2009, Hardcover, 319 pages, SciTech Publishing, 2009, List Price $ 89. This is an easy to read book which covers a broad range of topics from basics like the radar equation and waveforms to advanced subjects like the Generalized Likelihood Ratio Test which is explained in simple terms. It complements the primary course book.

The course lectures, its books, many reprints and notes provide an ideal introduction to the principles of phased array antenna design and adaptive arrays. The course notes are updated to 2010 technology. The course covers in easy terms sidelobe cancellation, full adaptive array processing without suffering its computation complexity (through the use of adaptive-adaptive array processing, beam-space processing, largest eigenbeam processing). Finally, Space-Time Adaptive Array (STAP) for airborne platforms will be explained and related to the displaced phase center antenna (DPCA).

This course is intended for the engineer or scientist not familiar with phased-array antennas as well as the antenna specialist who wants to learn about other aspects of phased-array antenna systems. The major emphasis will be on the system aspects of phased-array systems.

Lecture #1: Monday Feb. 22

Phased Array Fundamentals:

Fundamental Principles of Electronically Scanned Array (ESA) explained with 1st generation tube COBRA DANE used as example. Covered will be: Near and Far Field Definitions, Phased Steering, Switched-Line Phase Steering; Time Delay Steering, Subarraying, Array Weighting, Monopulse, Duplexing, Array Thinning, embedded element, Dual Polarized Circular Waveguide Element, Advantage of Triangular Lattice Over Square Lattice, Tour of COBRA DANE (6 stories) via color slides1

Lecture #2: Monday March 1

Linear Array Fundamentals

Conditions for no grating lobes; beamwidth vs scan angle; sine space; Array Factor; sidelobe level vs antenna beamwidth; directivity; antenna efficiency factors; array weightings; element gain paradox; array frequency scanning; array bandwith; monopulse difference patterns.

Lecture #3: Monday March 8

Planar Arrays:

Array Factor for planar array; array separability; sine-space (siná-sinß space, u,v space); grating lobes location; triangular vs rectangular lattice; directivity; very useful bell curve approximation; array thinning system issues.

Lecture #4 Monday March 15

Array Errors:

Effects of element phase and amplitude element errors and failures; simple physical derivation of error effects; paired echo theory; subarray errors; quantization errors; examples.

Lecture #5 Monday March 22

Radiating Elements:

Waveguide; dipole; slotted waveguide; microstrip patch; stacked patch; notch (wideband); spiral; matching (wide-angle); waveguide simulator; practical limitations, mutual coupling and array blindness; scattering impedance matrices; design procedure.

Lecture #6 Monday March 29

Active Phased Arrays:

2nd generation solid state hybrid active electronically scanned array (AESAs) covered using PAVE PAWS as example, T/R Module Introduced, Cross Bent Dipole Element, Mutual Coupling, Array Blindness, Tour of PAVE PAWS (6 stories) via color slides. 3rd Generation AESAs: THAAD SPY-3, IRIDIUM, F-15 APQ-63(V)2, APG-79, XBR array, GaAs integrated circuit (Monolithic Microwave Integrated Circuit [MMIC]) arrays.

Lecture #7 Monday April 5

Array Feeds

Corporate and space fed; Reactive (lossless) and matched (Wilkinson); even/odd node analysis. Serial; Ladder; Lopez; Blass; Radial, Butler matrix; microstrip/stripline; Rotman Lens; SLQ-32; PATRIOT; reflectarray.

System Considerations

Detection Issues: sequential, beam shape loss; receiver and A/D dynamic range; polarization; array noise figure and system temperature taking into account array mismatch.

Phase Shifters:

Diode switched-line, hybrid-coupled, loaded-line; ferrite phase-shifters: non-reciprocal latching; diode vs ferrite; MEMS (Micro-Electro-Mechanical Systems) and its potential for a low cost ESA.

Lecture #8 Monday April 12

Limited Scan (Limited Field of View [LFOV]) Arrays:

Explained using simple high school optics for TPS-25, 1st ESA put in production. Fundamental Theorem specifying minimum number of phase shifters needed for a specified scan angle. Method for realizing this minimum using overlapped array antenna elements as with HIPSAF lens array system and Microwave Landing System (MLS) array system; reflector; randomized oversized elements; sum and difference patterns; Use of spatial filters to reduce grating lobes.

Hemispherical Coverage Dome Antenna

Lecture #9 Monday April 26

Phased Array Breakthroughs and Future Trends — Part 1

Digital beam forming (DBF) AESAs: SMART-L, AMSA, MESA, SAMPSON, ROTHR, and Elta EL/M-2488 4-faced 2500 elements/face S-band active array using digital beam forming (DBF) at the element level, a MAJOR BREAKTHROUGH; low cost arrays (35 GHz array, $40/element using single chip T/R modules; MEMS arrays; car blind spot 24 GHz array (just $100’s for whole radar) - a phased array may be in everyone’s future); next multibeam, multielement (8 or more) receive or transmitter array circuitry (phase shifters, gain control, combiner) on a single SiGe/BICMOS chip - amazing.

Sidelobe Cancellers (SLC)

The simple single-loop, feed-forward canceller is first introduced in easy terms. This is followed by a discussion of the simple single-loop feedback canceller with and without hard limiting. The normalized feedback SLC will also be covered. Presented will be their performance; transient response and cancellation ratio. Next the multiple-loop SLC (MSLC) will be covered. Applied to the MSLC will be the Gram-Schmidt, Givens and Householder orthonormal transformation methods for LSE developed for the Tracking and Prediction Made Easy lecture. Systolic array implementations will be given.

Lecture #10 Monday May 3

Fully Adaptive Arrays

The optimum weight for a fully adaptive array is developed using a very simple derivation. Methods for calculating this optimum weight are given using the Sample Matrix Inversion (SMI) algorithm, the Applebaum-Howells adaptive feedback loop method, a recursive method, and Gram-Schmidt, Givens and Householder orthonormal transformations developed for the tracking problem and for the MSLC. The use of eigenvector beams and a whitening filter will also be developed. It will be shown how the latter reduces the transient response. Methods for obtaining the benefits of a fully adaptive array without its high computation and large transient time disadvantages are given. These are the adaptive-adaptive array processing procedures, the use of eigenbeam space, and the method of finding the largest eigenvalues and in turn their eigenbeams. The STAP algorithm will be introduced. Finally the use of the Gram-Schmidt orthonormal transformation followed by a whitening filter will be applied to the reduction of SAR map speckle – the Polarization Whitening Filter

Phased Array Breakthroughs and Future Trends — Part 2

The Part 2 breakthroughs covered are: 1. GaN technology (offers 10X higher power and higher efficiency, > 1000 W peak with single transistor package, replacement potential of ferrite circulator in T/R module), SiC, SiGe; 2. Advantages of DBF (almost 3 dB lower search power and occupancy, adaptive-adaptive array processing equivalent to principal component or beam space processing, antenna lower sidelobes); 3. Revolutionary micromachining (Ka-band 4X4 array and its Butler beam former on one chip); 4. Real radar world applications for Multiple-Input Multiple-Output (MIMO) architectures (coherent combining of N identical small radars to achieve a factor of N3 better sensitivity; adaptive control of the radar transmitter antenna pattern to obtain better clutter rejection for OTH phased array radars); 5. Arrays with instantaneous bandwidths of 10:1 and 33:1; 6. 4" SAR imaging at a distance of 6 km; 7. Interferometer 3-D SAR obtained with 2 passes of single antenna SAR instead of with 1-pass with 2 antennas (UAVSAR); 8. Use of probing signal to increase the dynamic range of nonlinear amplifiers and A/Ds by 20 dB; 9. Invention of very small light modulators on silicon (Si) for use to communicate between cores processors on chip at 100 times the speed with 1/10th the power, 100’s to 1000’s core processors on chip, a supercomputer on a chip; 10. Invention of carbon transistors having potential for 1000X clock speed of Si transistors (terahertz vs. GHz), has lower resistance and better heat conduction; 11. Very low cost radars — $80 for baseball speed measurement radar and $20 toy speed radar – now every radar engineer can buy his own personal radar; 12. Upgrade of Haystack radar to 95 GHz to provide 1 cm ISAR imaging of satellites; 13. Knowledge aided STAP (10-15 dB improvement in SIR when use made of maps to put nulls in antenna pattern where clutter is and to edit out road echoes); Principal Component and S-methods for improved ISAR imaging; Metamaterials now allow focusing to beyond diffraction limit and provides wide band conformal arrays.

Decision (Run/Cancel) Date for this Courses is Monday, February 15, 2010

FEES

Payment received by Feb 11: IEEE Members $395

Payment received by Feb 11: Non-members $435

Payment received after Feb 11: IEEE Members $435

Payment received after Feb 11: Non-members $495