6 2LI.3G5 crfp 2. INGWEERING LIBRARY NTENNA LABORATORY Technical Report No. 39 o LOG PERIODIC DIPOLE ARRAYS SEP 2 1 * ^ I ^ ■ by Dwight E. Isbell 10 June 1959 Contract No. AF33{616)-6079 Project No. 9-(l 3-6278) Task 40572 Sponsored by: WRIGHT AIR DEVELOPMENT CENTER ELECTRICAL ENGINEERING RESEARCH LABORATORY ENGINEERING EXPERIMENT STATION UNIVERSITY OF ILLINOIS URBANA, ILLINOIS Return this book on or before the Latest Date stayrripe.d , below. University of Illinois Library DtU 27 1962 372 MAL22JI72 1.1., I Ml ANTENNA LABORATORY Technical Report No„ 39 LOG PERIODIC DIPOLE ARRAYS by Dwight E. Isbell 1 June 1959 Contract AF33 (616)-6079 Project No. 9- (13-6278) Task 40572 Sponsored by: WRIGHT AIR DEVELOPMENT CENTER Electrical Engineering Research Laboratory Engineering Experiment Station University of Illinois Urbana, Illinois ACKNOWLEDGMENT The author wishes to thank Dr„ G„ A. Deschamps and Dr. P. E. Mayes for their contributions in the way of helpful discussions during the course of this work, Financial support for the program was received from the United States Air Force, WADC, Wright-Patterson Air Force Base, Ohio. The assistance of Mr. William B. Guffey, who performed most of the experi- mental work, is sincerely appreciated. ABSTRACT A new class of coplanar dipole arrays is introduced . The antennas described provide unidirectional radiation patterns of constant beamwidth and nearly constant input impedances over any desired bandwidth. The broadband properties are achieved by making use of the principles of log periodic antenna design. One of the antennas discussed provides approx- imately 8 db of directive gain with an associated input standing wave ratio of 1„2:1 on a 75 ohm feeder, and this performance is independent of frequency , The free space properties of several of these arrays have been measured and the results are presented . The antenna configuration is simple, permitting practical methods of fabrication, and the design should prove useful in many applications. It makes possible, for example, the construction of "all wave" rotatable beams of very low cross section for use in the hf to uhf spectrum. Digitized by the Internet Archive in 2013 http://archive.org/details/logperiodicdipol39isbe CONTENTS Page Acknowledgment Abstract 1 „ Introduction 1 2, Some General Considerations 2 3 , Experimental Results 7 3,1 Model Description 7 3„2 Effect of Truncation 7 3.3 Input Impedance 11 3„4 Radiation Patterns 17 3„5 Bandwidth Control 17 4, Conclusions 30 References 31 ILLUSTRATIONS Figure Number Page 1. Side by Side Coplanar Array 3 2. Two Methods of Excitation 5 3, Schematic Diagram of the Array 8 4, Connection of Elements to Balanced Feeder 9 5„ The Array as a Two Port Network 10 6 : Measurement Apparatus 12 7, Radiating Efficiency vs. Antenna Size 13 8, Input Impedance, t = .95 14 9, Input Impedance, T = ,89 15 10 Input Impedance, t = .81 16 11, Radiation Pattern Models 18 12, Typical Field Patterns, T = „95 19 13, Typical Field Patterns, T = .89 20 14, Typical Field Patterns, T = .81 21 15, Directivity vs. t and a 22 16, Bandwidth Control Model 24 17, Field Patterns of Bandwidth Control Model 25 18 Field Patterns of Bandwidth Control Model 26 19, Field Patterns of Bandwidth Control Model 27 20, Directive Gain of Bandwidth Control Model 28 21, VSWR with Respect to 72 ohms 29 1. INTRODUCTION Log periodic antenna design has been the subject of several papers over the past few years. The concept was first introduced in connection with a plane slot radiator having bidirectional, linearly polarized, radi*- ation patterns of constant beamwidth and essentially constant input imped- ance over better than ten to one bandwidths. Since that time many exten- sions of the original structure have been introduced provi ding a large choice of electrical characteristics all of which are virtually independent 2 3 of frequency. ' Log periodic antenna designs are available, for example, which provide omnidirectional, bidirectional, or unidirectional radiation patterns and either linear or circular polarization. The basic unidi- rectional elements all have moderate directive gains, and it has been 4 shown that high gains are possible through application of array techniques 5,6 or by using the antennas as primary sources for large reflectors ' . The antennas discussed in the following paragraphs provide electrical characteristics which are similiar to those of s.ome of the antennas described in the above referenced papers, but they represent a departure in form. The log periodic designs which have been introduced to date have all been variations of a basic type involving combinations of a single composite element which is shaped to provide the log periodic characteristics The antennas introduced here demonstrate that the log periodic principles can be applied to the design of arrays of conventional elements with fre- quency independent performance resulting. An important consequence of this as will be seen, is that these antennas permit at least a qualitative analysis of their operation in terms of familiar ideas, and they further tend to increase insight with respect to the operation of the original log periodic antennas. 2. SOME GENERAL CONSIDERATIONS Although it has not, as yet, been possible to obtain precise physical understanding of the operation of the successful frequency independent antennas it is possible to put forth certain qualitative arguments in that direction. The following is an attempt to induce these arguments into the design of a wide band array using conventional elements. If frequency independent performance is sought from a structure composed of resonant elements it is clear that the resonances must be staggered in order that as frequency is varied the function of the resonant element is transferred smoothly from one element to the next. In the case of an antenna array composed of similiar discrete elements this means that the physical dimensions of the elements must be scaled from one to the next in such a way that the desired frequency range is covered with elements of overlapping response characteristics. Since the characteristics of antenna elements are determined in part by their surroundings, it is necessary also to scale the environment. Considering now a coplanar array of side by side dipoles in accordance with the above ideas ; an arrangement of the type shown in Figure 1 is obtained „ The lengths of the dipoles are related by a constant scale factor t as defined in the figure. That is, given the length L of the element of order in the array, the length of the elements of order n will be given by T L where n takes on all integral values, positive or negative. Since it is also necessary to scale the environment, the spacings A s between elements must be related in the same manner. If carried to the limit the array converges to the point on the left as n — > - and becomes infinite in extent on the right as n-=!»oo. If the elements of Figure 1 are fed in series by means of a common feeder from a generator located at point 0, the infinite structure will possess the property of logarithmic periodicity. That is, whatever the fields produced by an excitation frequency f they will be reporduced (apart from a change of scale) at all other frequencies given by T f. The variation in the fields between these frequencies will depend upon the degree of overlap in the individual element responses. ■ ' ' h as, m+\ AS, AS m _, o I — I — • • • 4 L L/n+i (T> + I = T L m - oo- I FIGURE 1 SIDE BY SIDE COPLANAR ARRAY 4 To be useful as a practical, broadband radiator it must be possible to truncate the array so that at all frequencies above some lower limit the truncated antenna performs like the infinite structure. This imposes a requirement for rapid attenuation of the incident wave along the feeder so that only negligible energy is reflected from the truncated end. If this situation occurs it follows that the array characteristic will be periodic in periods of bandwidth 1/t : 1„ If, furthermore, the variation in perform- ance is negligible over a period then the antenna may be broadbanded to any desired degree by simply adding elements according to the general scheme. Consideration must now be given to the method 6f feeding the array. Two methods of introducing the common feeder are shown in Figure 2. In both cases the dipole elements are attached to the feeder so that their respective terminal impedances appear in parallel across the line at the logarithmically varying intervals A s In 2(a) the currents in the elements have the same relationship as the terminal phases so that considering the elements closely spaced,, the phase progression of the currents in the array is to the right. In 2(b), however, the elements are connected so that a phase constant of IT radians is added to the terminal phase of each element. This is accomplished mechanically by twisting the feeder 180 between each element. A choice between these methods of feeding can be made on the basis of the following reasoning, If the array is to have the property of unlimited bandwidth with constant electrical characteristics, then it is clear that at any given frequency only a portion of the dipole elements can be excited „ These elements must be such that the length of the excited portion of the array will be approximately constant in terms of the normal- ized distance x/X measured from the array vertex. The elements which are not excited by the feeder should make no contribution to the performance so that coupling with the radiated field would be undesirable. It appears then that the radiation pattern of the array should have a null in the direction of the incident energy on the line. It has been pointed out that the array of Figure 2«a) is fed so that the element phase progresses to the right, and since this type of excitation is a condition for end fire in that direction this would seem to be an unsatisfactory method. Qualitative -• •- -• •- (a) fb) FIGURE 2 TWO METHODS OF EXCITATION consideration of the array of Figure 2(b) however provides a more promising picture In this case the short closely spaced elements are seen to be almost in phase opposition and hence radiate very little energy Further out along the array where the spacing is larger and the elements are longer, the elements will radiate and the mechanical phase reversal effects a reversal in the direction of phase x progression so that the radiation pattern is endfire in the direction of the input terminals. With this method of feeding, the elements which radiate the most energy will be those near resonant lengths and their combined radiation pattern is toward the array apex as desired. As the frequency is increased the radiating elements appear closer to the apex of the array by an amount proportional to the change in wavelength so that the normalized array length remains approxi- mately constant as the frequency is varied An experimental program was carried out to determine the electrical properties of arrays of the "ype sho^n in Figure 2(b<, and it was found that this antenna, for certain parameter values, has essentially frequency independent performance over any desired bandwidth. 3. EXPERIMENTAL RESULTS 3.1 Model Descri ption The parameters describing the experimental arrays are shown in Figure 3. The structure is defined in terms of the geometric ratio t the angle a, and the characteristic impedance of the feeder. The feeder impedance has not been found to be critical, and for most of this investigation 105 ohm rigid o open wire line was used. The method of obtaining the 180 phase reversal between elements is shown in the sketch of Figure 4, The array is fed by means of a coaxial cable brought to the input terminals through one of the balanced line conductors. No balun is required for this. method of feeding. 3.2 Effect of Truncation One of the first things to be determined experimentally is the effect of truncation of the array. It is necessary that the electrical properties of the truncated structure converge to characteristic values as the frequency is increased as previously mentioned, it should be the case that above some low frequency limit, determined by the maximum physical dimension of the array, the properties are identical to those of the infinite structure. If the antenna array is thought of as a linear passive, four terminal, network with input terminals at the apex and output terminals at the trun- cated end then it may be considered as shown in Figure 5. It is required that for the truncated antenna, the transmitted power P , through the net- work, be only a negligible part of the net power input, P.-P . In other words the transmission coefficient S of the network must be small. It 12 is essential that the antenna configuration convert, efficiently, the power incident on the feeder to radiated power P The radiating efficiency is R defined as \ and in terms of the scattering coefficients this becomes 1-lS \ 2 -\s |* n s __ U U 1- S 11 •z 5 u c Q I CD + r X £■ £ >"N <==»< x If 1 C + c d c ex -H o< OS < § < M Q o w g o 1-4 Pn \ \ X it \ \ ^ « o FEED POINT FIGURE 4 CONNECTION OF ELEMENTS TO BALANCED FEEDER 10 INPUT I PLANE OUTPUT | PLANE radiated power P„ = P. - P - P, R i r t radiating efficiency n n = R P.-P 1 r In terms of the scattering coefficients p = Is r p. p A = Is r p t 12 i so that ^T i-ls l 3 ~!s I 2 11 12 1-IS 11 FIGURE 5 THE ARRAY AS A TWO PORT NETWORK 11 Note that the efficiency so defined does not take into account the conductor losses in the elements. A simple method of determining the scattering parameters of a two part 7 network was introduced by Deschamps With this method the image of the unit circle in the output plane is determined experimentally and plotted in the input reflection coefficient plane. This is accomplished by a simple series of slotted line measurements of the input reflection coefficient as a function of pure reactive terminations at the output terminals. Deter- mination of the unit image circle and its iconocenter is sufficient for determination of the scattering matrix elements. The experimental apparatus for making this measurement is shown in Figure 6 „ The individual antenna elements were made from thin copper strips formed at one end so that they snap in place on the conductors of the open wire line„ This procedure was found to be both simple and satisfactory although care was necessary in making the elements to ensure that they stood perpendicular to the feeder. The radiating efficiency was measured for several of the arrays as a function of size. This was accomplished by starting with a few small elements near the apex in place and then measuring the scattering coeffi- cients of the network as each additional element was snapped in place. A curve of radiation efficiency as a function of array size is shown in Figure 7 for one of the models tested „ Notice that by the time an element of length \i'2 is added nearly 80% of the power is being radiated. 3,3 I nput Impedance The input impedances of the experimental models were measured using the same set up as shown in Figure 7 a The array elements were arranged so that the terminals of the shortest dipole appeared at the junction between the coaxial cable and the balanced line. This procedure effectively truncates the array at both ends providing upper and lower frequency limits accordingly. Between these frequency limits the input impedance was found to behave in a manner characteristic of the design parameters t and a, and several combinations were investigated. The results of the impedance measurements are shown in Figures 8, 9, and 10, Each figure represents the variation of the input impedance as a 12 CO 0< 8! g w s w CO w s CD w o I— I 13 1 1.0 .9 -6 .7 .6 .5 .4 .3 f / r=.89 a =45' V t— ^T *r** J I I I I I L o .3 .4 .5 .£, .7 .8 .3 \-0 L A. FIGURE 7 RADIATING EFFICIENCY VS . ANTENNA SIZE 14 E o of 100 t V / qo SWR / W . / / r RO / / > / / 10 / / j ^ - u CO a\ Ro 50 \j L o 20 30 C< - DEGREES 40 50 FIGURE S INPUT IMPEDANCE, T = .95 15 100 / i /< / ) 9D / / / c / / „ so If) £ SWR. ^y / A / / 1 X i k / / t X. c / / ^y> C k ^ __^j: / i [ xj i r\o fe>U 4 k em o 10 ZO 30 C< - DEGREES 40 50 FIGURE 9 INPUT IMPEDANCE, T = .89 16 100 30 IW I| WW I Wli IW M ^I^ ■ H lf 1» M H i n |l I « 20 « = 10 0C=35 ( H PLANE 0(= 10 H PLANE a= 35* FIGURE 13 TYPICAL FIELD PATTERNS, T = „89 E PLANE o(= 15 a - 30 H PLANE H PLANE ck = 15 0(=30 FIGURE 14 TYPICAL FIELD PATTERNS, T = .81 22 o N 13 U La Of . •4 \ J f=,95 / X V 4 *\ \< » fc- • ■ > 7X89 > "^ r*&\ "»■*. ^-^^ -^ — — i k 20 ; .." #0 so Ct - DEGREES FIGURE 15 DIREC riVITl YS , t And 23 ' id t h The upper and lower frequency limits will be determined by lengths of rhe shortest and longest elements of the array respectively. To determine this bandwidth for a particular array the antenna shown in Figure 16 was constructed. This antenna is defined by a t of , 95, a equal to 10 degrees, |j equal to 2 1/2 inches, and the shortest element half the length of the longest The array is 7 1/2 inches long and there are a total of fifteen dipoles included,, Radiation patterns for this array are shown in Figures 17, 18, and 19 over the band 1100 to 1800 mc/sec, and the directive gain, estimated on the basis of half power beamwidth, is shown in Figure 20 „ The minimum front- to-back ratio is 17 db and the directivity is better than 9 db over isotropic from 1130 to 1750 mc/sec The variations in the directivity curve correspond closely to the periodicity t„ A scaled up model of the array was assembled on the balanced line of the impedance measuring set up of Figure 7, and its input impedance was measured over a range corresponding to that of the radiation patterns above „ The results of this measurement are shown in Figure 21 in terms of the standing wave ratio produced on a 72 ohm transmission line. If the usable bandwidth of this antenna is taken to be the range from 1100 to 1800 - > o Uj a. o 2 iOCO (200 I80O 1400 1600 FREQUENCY - mc /sec FIGURE 20 DIRECTIVE GAIN OF BANDWIDTH CONTROL MODEL 2O0O 29 g (- < I z Q 2 Lu O 6.0 50 4.0 3.0 20 1 \y fooo 1200 1400 1&00 \800 2000 FREQUENCY - mc/sec FIGURE 21 VSWR WITH RESPECT TO 72 OHMS 30 4, CONCLUSIONS The arrays discussed in the foregoing paragraphs should prove useful in several applications. The model used to demonstrate bandwidth control shows that these antennas will make excellent rotatable beams, superior in many respects to the parasitic types currently in use. It is interesting to compare, for example, the antenna of Figure 16 to a 5 element Yagi. A wide spaced, five element, Yagi adjusted to provide a midband f ront-to-back ratio of 25 db, will provide a 7% bandwidth with a front-to- back ratio of approximately 15 db at the edges . The midband directive gain of this antenna is slightly better than 10 db over isotropic, and its length is about ,85 wavelengths. The log ;periodic beam of Figure 16 has fifteen elements but is only .73 wavelengths long at the low frequency end. The directivity stays above 9 db with the front-to-back ratio better than 17 db through a bandwidth of 43 percent, and the elements need no adjusting for this performance, DuHamel and Berry have shown that the original log periodic elements can be arranged to provide directivities of up to 20 db, and those same principles may be applied to the dipole array where higher gains are required, Omnidirectional horizontal polarization and unidirectional circular polarization should be achievable by using the methods introduced by DuHamel and Ore In addition to the practical usefulness of the log periodic dipole arrays there is another equally interesting and important aspect of the design, The fact that these structures are made up of conventional linear elements seems to invite analysis intterms of familiar transmission line and array theory. To be sure., the problem is not a simple one even so, but its solution would be well worth while in the study of frequency independent antennas. This problem is presently being considered in this laboratory. 31 REFERENCES 1„ R. H„ DuHamel and D. E Isbell, "Broadband Logarithmically Periodic Antenna Structures," 195 7 IRE National Convention Record , Part I, page 119, March 1957, Also, University of Illinois Antenna Laboratory Technical Report Number 19. Contract AF 33(616) -3220, WADC, May 1957, 2 D,E, Isbell, "Non-Planar Logarithmically Periodic Antenna Structures," Abstracts of the Seventh Annual Symposium on the USAF Antenna Research and Development Program, October 1957. Also, University of Illinois Airtelin^^aboraTory "Technical Report Number 30, Contract AF33(616)-3220, WADC, February 1958.. 3. R.H. DuHamel and F.R. Ore, "Logarithmically Periodic Antenna Designs," 1958 IRE National Convention Record, Part 1, page 139, March 1958. A R,H, Duhamel and D„G. Berry, "Logarithmically Periodic Antenna Arrays," 1958 IRE West Coast Convention Record , August 1958. 5, D.E. Isbell, "A Log-Periodic Reflector Feed," Proc. IRE, (to be published) 6 U R.Ho DuHamel and F.R„ Ore, "Log Periodic Feeds For Lens and Reflectors," 1959 National IRE Convention Record, Antennas and Propagation Section, March., 1959 " " ~~ ~~~ G. A Deschamps, "Determination of Reflection Coefficients and Insertion Loss of a Wave-Guide Junction," J. Appl . Phys . , Vol. 24, No. 8, pp 1046-50 August 1953 . ANTENNA LABORATORY TECHNICAL REPORTS AND MEMORANDA ISSUED Contract AF33 ( 616 /-310 "Synthesis of Aperture Antennas," Technical Report No. 1 , C.T.A, Johnk October, 1954 A Synthesis Method for Broad-band Antenna Impedance Matching Networks," Technical Report No„ 2, Nicholas Yaru, 1 February 1955, The Asymmetrically Excited Spherical Antenna/' Technical Report No. 3, Robert C. Hansen, 30 April 1955, Analysis of an Airborne Homing System,"' Technical Report No. 4, Paul E, Mayes, 1 June 1955, (CONFIDENTIAL) ~~ ~~ Coupling of Antenna Elements to a Circular Surface Waveguide,' 1 Te chnical Report No . 5, H E, King and R. H, DuHamel, 30 June 1955 Input Impedance of a Spherical Ferri te Antenna wigh a Latitudinal Current," Technical Report No, 6, W, L Weeks, 20 August 1955, Axially Excited Surface Wave Antennas," Technical Report No 7, D. E, Royal, 10 October 1955 Homing Antennas for the F-86F Aircraft (450-2500mc), ! Technical R eport No._8 P r E Mayes, R F. Hyneman, and R. C Becker, 20 February 1957, (CONFIDENTIAL) Ground Screen Pattern Range," 1 Technical Memorandum No. 1, Roger R, Trapp, 10 July 1955, ~ ~~ ~ Con t rac t AF3 3(616) - 3220 Effective Permeability of Spheroidal Shells," Technical Report No, 9, E J Scott and R H DuHamel, 16 April 1956 An Analytical Study of Spaced Loop ADF Antenna Systems,'" Technical Report No 10, D G Berry and J. B, Kreer, 10 May 1956. A Technique for Controlling the Radiation from Dielectric Rod Wavequides, "' T echnical Rep ort No, 11, J W Duncan and R H DuHamel, 15 July 1956„ Directional Characteristics of a U-Shaped Slot Antenna," Technical Report No. 12, Richard C Becker, 30 September 1956 Impedance of Ferrite Loop Antennas,"' Technical Report No 13, V. H„ Rumsey and W. L Weeks, 15 October 1956 Closely Spaced Transverse Slots in Rectangular Waveguide " Technical Report No 14, Richard F. Hyneman, 20 December 1956 , Distributed Coupling to Surface Wave Antennas," Technical Report No, 15. Ralph Richard Hodges, Jr,, 5 January 1957. "The Characteristic Impedance of the Fin Antenna of Infinite Length,"' Technical Report No, 16 , Robert L. Carrel, 15 January 1957„ On the Estimation of Ferrite Loop Antenna Impedance," Technical Report No, 17, Walter L. Weeks, 10 April 1957, A Note Concerning a Mechanical Scanning System for a Flush Mounted Line Source Antenna," Technical Report No. 18 , Walter L, Weeks, 20 April 1957 . "Broadband Logarithmically Periodic Antenna Structures," Technical Report No, 19 , R„ H DuHamel and D E. Isbell, 1 May 1957 . "Frequency Independent Antennas," Technical Report No, 20, V. H v Rumsey, 25 October 1957, The Equiangular Spiral Antenna," Technical Report No. 21, J. D, Dyson, 15 September 1957, Experimental Investigation of the Conical Spiral Antenna," Technical Report No, 22, R„ L. Carrel, 25 May 1957, "Coupling Between a Parallel Plate Waveguide and a Surface Waveguide," Technical Report No, 23, E.J. Scott, 10 August 1957. 'Launching Efficiency of Wires and Slots for a Dielectric Rod Waveguide," Technical- Report No. 24, J.W. Duncan and R H„ DuHamel, August 1957, "The Characteristic Impedance of an Infinite Biconical Antenna of Arbitrary Cross Section," Technical Report No. 25 , Robert L, Carrel, August 1957, Cavity-Backed Slot Antennas," Technical Report No, 26 , R.J. Tector, 30 October 1957, "Coupled Waveguide Excitation of Traveling Wave Slot Antennas," Technical Report No 27, W,L. Weeks, 1 December 1957. Phase Velocities in Rectangular Waveguide Partially Filled with Dielectric," T echnical Report No, 28 , W,L Weeks, 20 December 1957, "Measuring the Capacitance per Unit Length of Biconical Structures of Arbitrary Cross Section," T echnical Report No. 29 , J.D, Dyson, 10 January 1958 Non-Planar Logarithmically Periodic Antenna Structure," Technical Report No. 30, D W isbell, 20 February 1958. 'Electromagnetic Fields in Rectangular Slots, " Technical Report No, 31, N„J„ Kuhn and P r E Mast, 10 March 1958, 'The Efficiency of Excitation of a Surface Wave on a Dielectric Cylinder," Tec hnical Report No, 32 , J.W, Duncan, 25 May 1958, "A Unidirectional Equiangular Spiral Antenna," Technical Report No 33 , J D. Dyson, 10 July 1958, 'Dielectric Coated Spheroidal Radiators," Technical Report No. 34, W.L. Weeks, 12 September 1958, "A Theoretical Study of the Equiangular Spiral Antenna,"' T echnical Report No, 35 , P,E Mast, 12 September 1958, Contr act AF33 (616 ) -6 079 "Use of Coupled Waveguides in a Traveling Wave Scanning Antenna, Technical Report No 36, R,H, MacPhie, 30 April 1959 DISTRIBUTION LIST One copy each unless otherwise indicated Armed Services Technical Information Agency Arlington Hall Station Arlington 12, Virginia 3 copies, 1 repro. Commander Wright Air Development Center Wright-Patterson Air Force Base, Ohio ATTN- WCLRS-6. Mr. F 9 E^ Burnham 3 copies Commander Wright Air Development Center ATTN: WCLNQ-4, Mr. M. Draganjac Wright-Patterson Air Force Base, Ohio Commander Wright Air Development Center ATTN: WCOSI, Library Wright-Patterson Air Force Base, Ohio Director Evans Signal Laboratory ATTN. Technical Document Center Bel mar, New Jersey Commander U.S„ Naval Air Test Center ATTN ET-315. Antenna Section Patuxent River, Maryland Chief Bureau of Ordnance Department of the Navy ATTM; Mr, C„H„ Jackson, Washington 25, D. C. Code Re 9a Commander Hq, A F, Cambridge Research Center Air Research and Development Command Laurence G. Hanscom Field ATTN CRRD, R, E„ Hiatt Bedford. Massachusetts Commander Air Force Missile Test Center Patrick Air Force Base, Florida ATTN; Technical Library Director Ballistics Research Laboratory ATTN: Ballistics Measurement Lab, Aberdeen Proving Ground, Maryland Office of the Chief Signal Officer ATTN. SIGNET-5 Eng. & Technical Division Washington 25, D. C Commander Rome Air Development Center ATTN: RCERA-1 D.Mather Griffiss Air Force Base Rome, New YOrk Airborne Instruments Lab,, Inc„ ATTN: Dr, E G. Fubini Antenna Section 160 Old Country Road Mineola, New York M/F Contract AF33 (616) -2143 Andrew Alford Consulting Engineers ATTN; Dr. A. Alford 299 Atlantic Avenue Boston 10, Massachusetts M/F Contract AF33 (038)-23700 Bell Aircraft Corporation ATTN: Mr a J, D t Shantz Buffalo 5, New York M/F Contract W-33(038)-14169 Chief Bureau of Ships Department of the Navy ATTN: Code 838D, L„ E. Shoemaker Washington 25, D,C. DISTRIBUTION LIST (CONTTTOED) McDonnell Aircraft Corporation ATTN Engineering Library M F Contract AF33 (600 r-8743 Lambert Municipal Airport St Louis 21, Missouri Dr L. Cutrona University of Michigan Aeronautical Research Center M F Contract AF33 (038) -21 573 Willow Run Airport Ypsilanti, Michigan Professor H J. Zimmermann Research Lab of Electronics Massachusetts Institute of Technology M F Contract AF33 v616 J-2107 Cambridge, Massachusetts Dr.. J A. Marsh .North American Aviation, Inc. Aerophysics Laboratory M F Contract AF33 (038)18319 12214 Lakewood Boulevard Downey, California Mr Dave Mason Engineering Data Section North American Aviation, Inc. M F Contract AF33 i'038'jl8319 Los Angeles International Airport Los Angeles 45. California Northrop Aircraft, Incorporated ATTN: Northrop Library Dept 2135 M F Contract AF33 ^00) -2231 3 Hawthorne, California Radioplane Company M F Contract AF33 <600, -23893 Van iVuvs, California Lockheed Aircraft Corporation ATTN C L ohnson P Box 55 M F N0a(s ■ -52-763 Burbank, California Republic Aviation Corporation ATTN: Engineering Library M F Contract AF33 (038 j»-14810 Farmingdale Long Island, New York Sperry Gyroscope Company ATTN Mr, B. Berkowitz M/F Contract AF33 i 038 > -14524 Great Neck Long Island, New York Mr, George Cramer Temco Aircraft Corporation Contract AF33~(600)21714 Garland, Texas George Giffin Farnsworth Electronics Co, Marked; For Cont, AF33 (600 > -25523 Ft „ Wayne, Indiana Mr James D Leonard North American Aviation, Inc Contract NOa(g) 54-323 4300 E. Fifth Avenue Columbus, Ohio Mr P D Newhouser Development Engineering Westinghouse Electric Corporation Air Arm Division Contract AF33 (600) -27852 Friendship Airport, Maryland Air Force Development Field Representative ATTN Capt Carl B, Ausfahl Code 1010 Naval Research Laboratory Washington 25, D.C. Chief of Naval Research Department of the Navy ATTN: Mr Harry Harrison Code 427 Room 2604, Bldg, T-3 Washington 25, DC. Robert Borts Raytheon Manufac t ;ring Company Wayland Laboratory, Wayland., Mas^ DISTRIBUTION LIST (CONTINUED) Svlvaaia El ectric -Products, lnc Electronic Defense Laboratory IT Contract DA 36-039-sc-75012 P.O Box 205 Mountain View, California En n is Kuhlman 7c McDonnell Aircraft P O Box 516 Lambert Municipal Airport St, Louis 21 Missouri Stanford Electronics Laboratory Stanford University ATTN Applied Electronics Lab. Document library Stanford, California Radio Corporation of America*. RCA laboratories Division Princeton, New Jersey Electrical Engineering Res, Lab u University of Texas Box 8026, University Station Austin, Texas Dr Robert Hansen 8356 Chase Avenue los Angeles 45, California Technical library Bell Telephone Laboratories 463 West Street New York 1 4 , New York Dr RE Beam Microwave Laboratory Northwestern University Evanston, Illinois Dr 3 H G Booker Department of Electrical Engineering Cornell University Ithaca, New York Applied Physics Laboratory Johns Hopkins University 8621 Georgia Avenue Silver Spring, Maryland Exchange and Gift Division The Library of Congress Washington 25, D C„ Mr. Roger Battie Supervisor, Technical Liaison Sylvania Electric Products, lnc, Electronic Systems Division P.O. Box 188 Mountain View, California Physical Science Lab„ ATTN: R. Dressel New Mexico College of A and MA State College, New Mexico Mrs c E,L. Hufschmidt, Librarian Technical Reports Collection 303 A Pierce Hill Harvard University Cambridge 38, Massachusetts Dr, R,H. DuHamel Collins Radio Company Cedar Rapids,, Iowa Dr„ R„F„ Hyneman 5116 Marburn Avenue Los Angeles 43, California Director Air University Library ATTN: AUL-8489 Maxwell AFB, Alabama Mary Lou Fields, Acquisitions Stanford Research Institute Documents Center Menlow Park 7 California Dr Harry Letaw, Jr Research Division Raytheon Manufacturing Co. Waltham 54, Massachusetts Canoga Corporation 5955 Sepulveda Boulevard M/F Contract AF08 (603)-4327 P. 0. Box 550 Van Nuys, California •DISTRIBUTION LIST (CONTINUED) Svlvaaia El ectric Products, Inc Electronic Defense Laboratory M F Contract DA 36-039-sc-75012 P.O Box 205 Mountain View, California Ennis Kuhlman % McDonnell Aircraft P 0, Box 516 Lambert Municipal Airport St„ Louis 21 Missouri Stanford Electronics Laboratory Stanford University ATTN* Applied Electronics Lab, Document Library Stanford, California Radio Corporation of America*, R,C A Laboratories Division Princeton, Mew Jersey Electrical Engineering Res, Lab, University of Texas Box 8026, Iniversity Station Austin, Texas Dr Robert Hansen 8356 Chase Avenue Los Angeles 45 ? California Technical Library Bell Telephone Laboratories 463 West Street New York 14, New York Dr, RE Beam Microwave Laboratory Northwestern University Evanston, Illinois Dr, H G Booker Department of Electrical Engineering Cornell University Ithaca, New York Applied Physics Laboratory Johns Hopkins University 8621 Georgia Avenue Silver Spring, Maryland Exchange and Gift Division The Library of Congress Washington 25, D C, Mr,, Roger Battle Supervisor, Technical Liaison Sylvania Electric Products, Inc, Electronic Systems Division P. 0, Box 188 Mountain View, California Physical Science Lab, ATTN: R, Dressel New Mexico College of A and MA State College, New Mexico Mrs„ E,L. Hufschmidt, Librarian Technical Reports Collection 303 A Pierce Hill Harvard University Cambridge 38, Massachusetts Dr, R,H. DuHamel Collins Radio Company Cedar Rapids, Iowa Dr„ R,F„ Hyneman 5116 Marburn Avenue Los Angeles 43, California Director Air University Library ATTN: AUL-8489 Maxwell AFB, Alabama Mary Lou Fields, Acquisitions Stanford Research Institute Documents Center Menlow Park^ California Dr„ Harry Let aw, Jr Research Division Raytheon Manufacturing Co. Waltham 54 ; Massachusetts Canoga Corporation 5955 Sepulveda Boulevard M/F Contract AF08 (603) -4327 P. 0. Box 550 Van Nays, California UNIVERSITY OF ILUNOIS-URBANA 391959