1084-4-Q Reports Control Symbol OSD-1366 Technical Report ECOM-0547-4 September 1968 Azimuth and Elevation Direction Finder Techniques Fourth Quarterly Report 1 April - 30 June 1968 Report No. 4 Contract DAAB07-67-C0547 DA Project 5A6 79191 D902-05-11 Prepared by J. E. Ferris and W. E. Zimmerman The University of Michigan Radiation Laboratory Department of Electrical Engineering Ann Arbor, Michigan E ~. must have prior approval of CG, U. S. Army Electronics Command, Ft. Monmouth, New Jersey, 07703, ATTN: AMSEL-WL-S.

1084-4-Q ABSTRACT During this reporting period all efforts have been directed towards the design and development of individual components. The components to be discussed are the broadband hybrids and phase shifters which may be employed with either bifilar or quadrafilar spirals and the electromechanical switch required for the azimuth - elevation direction finder. Typical experimental data is presented for engineering models of the above components. The data processing equipment has been received from the supplier and is now being evaluated and debugged. ii

1084-4-Q FOREWORD This report was prepared by The University of Michigan Radiation Laboratory of the Department of Electrical Engineering under Contract DAAB07-67-C-0547. This contract was initiated under United States Army Project No. 5A6 79191 D902-05-11 "Azimuth and Elevation Direction Finder Techniques". The work is administered under the direction of the Electronics Warfare Division, Advanced Techniques Branch at Fort Monmouth, New Jersey. Mr. S Stiber is the Project Manager and Mr. E. Ivone is the Contract Monitor. This report covers the period 1 April through 30 June, 1968. The material reported herein represents the results of the preliminary investigation into the study of techniques for designing broadband circularly polarized azimuth - elevation direction finder systems. The authors wish to express their thanks to Messrs. A. Loudon, E. Bublitz, K. Jagdmann and W. Henry for their efforts in the experimental work that has been performed during this reporting period, and M. Gurney for his efforts in the mechanical design of the switch. 111

1 084-4-Q TABLE OF CONTENTS ABSTRACT ii FOREWORD iii LIST OF ILLUSTRATIONS v I INTRODUCTION 1 II BALUN SYSTEM FOR ANTENNAS 3 Inm ELECTROMECHANICAL SWITCH 10 IV COMPUTER AND PERIPHERAL EQUIPMENT 20 V CONCLUSIONS 21 DD FORM 1473 iv

1084-4-Q LIST OF ILLUSTRATIONS 2-1 Phase Angle Between Output Terminals of Tandem 8. 3db Couplers 5 2-2 Phase Angle Between Output Terminals of the Stripline Balun 6 3-1 Engineering Models of Capacitive Junction of Electromechanical Switch 11 3-2 VSWR of a Single Switch Terminal 12 3-3 Sketch of Switch Capacitive Junction (Not to Scale) 14 3-4 Capacitive Junction Impedance 16 3-5 Drawing of Electromechanical Switch 17 3-6 Drawing of Electromechanical Switch Assembly 18 3-7 Electrome~chanical Switch and Drive Assembly 19 v

1084-4-Q I INTRODUCTION An amendment, extending the present contract to 30 November 1968 has been formalized. During this, the fourth quarter, efforts have been continued toward the design and fabrication of components required for the azimuth - elevation direction finder (DF) being developed by the Radiation Laboratory of the University of Michigan. The function of the azimuth - elevation DF system is to collect the relative signal levels from each of the antennas (17) associated with the DF system. The above data is evaluated and the pointing direction (associated with each antenna) of the incoming signal is computed and optically displayed by the data processing equipment. As a design goal the accuracy of the system is to be + 20 in azimuth and + 50 in elevation. A thorough discussion of the theory of the DF system and the components associated with it have been presented in the first and second quarterly reports (ECOM-0547-1 and 2). Therefore, this report will again be restricted to the experimental results (as was the case in ECOM-0547-3) that have been obtained during this reporting period. Efforts have been continued to be expended on the development of a balun that may be employed with either a bifilar planar spiral or a quadrafilar log conical spiral. Previously it has been noted that the quadrafilar antenna has been selected because it exhibits the required pattern characteristics to ensure accurate directional predictions over the 5:1 frequency band (600 - 3000 MHz). However, consideration is also being given to the feasibility of employing a flat planar bifilar spiral. The balun networks required for either of the above antenna configurations are similar and only a slight modification is required to use the same balun with a bifilar or a quadrafilar antenna. The balun network for the bifilar spiral consists of one broadband hybrid and one broadband 900 phase shifter. For the quadrafilar the balun consists of 3 hybrids and one 900 phase shifter. The present status of the development of these 1

1 084-4-Q components is discussed in Chapter II. The design and development of a single pole 17 throw broadband electromechanical switch has continued during this quarter and the deliverable model of the switch is now being manufactured. The switch is designed to operate at several rotational rates (10) in the 1-1000 rpm range. The circuitry associated with the electromechanical switch to alert the computer as to when data is or is not to be collected has been designed and a model fabricated to be installed in the system. The present status of the switch and its associated components is discussed in Chapter mI. Chapter IV discusses the status of the data processing equipment and its associated equipment which has been supplied by the S. Sterling Company. 2

1084-4-Q II BALUN SYSTEM FOR ANTENNAS Articles in the open literature on broadband coaxial couplers have stressed the need for extremely high mechanical tolerances to be associated with the center conductor width, overlap and separation between the stripline and ground planes. Earlier experimental work (at this laboratory) with the stripline couplers and the 900 phase shifter, required for the balun system, was conducted employing crude tolerances for the above item. Although the results were not outstanding, the components exhibited predictable responses. To evaluate the effect of tolerances, a stripline coupler was etched from a 4:1 scale drawing. The drawing was photo-reduced and a coupler was etched using the photo negative. This coupler was tested to determine the effect of employing tighter tolerances in printing the conducting filaments and assembly of the coupler. Preliminary data showed that the coupler's electrical characteristics were quite similar to the coupler employing crude tolerances and made from brass shim stock. The major difference appears to be in the isolation of port 4, which is a non-coupled port. But even here the two sets of data did not differ significantly. Time does not permit a detailed study of the effect of tolerances on the overall coupler performance but at present there is an indication that tolerances are not as critical as one might expect from reading reports in the literature. Pictures of broadband couplers generally show them to have 450 miter joints at the interesction of the quarter wavelength sections of the coupler. The reason given for using the 450 miter bends is that it reduces the reflections from the junction and improves the overall coupler performance. In our work with these couplers, using both the sharp 900 transition and the mitered 450 transition, we have found the 450 transition reduces the coupling of the stripline coupler. This reduction in coupling is believed to be due to the orthogonal component of currents in the mitered section. 3

1084-4-Q This reduction in coupling is especially evident in the center conductor which has a higher coupling coefficient. Therefore, the overlap that is required to give a particular coupling with a 90~ transition must be increased to give the same coupling 0 when one is using 45 mitered transitions. Reflectometer data and the coupling data do not show a great increase in performance by using the 45 mitered joints over the 90~ transitions. Impedance discontinuities of the 900 cross overs can be greatly reduced by staggering the cross over such that a more nearly constant line width is maintained through the transition. This means that the transition point on one side of the stripline is displaced from the transition point on the other side of the line to maintain a constant or more nearly uniform line width across the transition. The phase shifter that is required in the balun network has been fabricated from Rexolite 2200 material and has been checked over the 5:1 operating band. The reference line for the phaTse shifter was constructed from 0. 141 coaxial line instead of using a stripline section of 50 Q stripline as will be used in the final model. Since the individual components of the balun were mounted in separate packages for individual testing, it was necessary to connect these components with coaxial cable for testing of the engineering model of the balun network. This is undesirable since the cabling involves extra connectors and loss that would not be present in the final version of the balun network. The average phase of the two tandem (8 and 10db) couplers was 83, instead of 90. This difference was due to the total coupling coefficient of the tandem coupler being lower than the design value of -3. Odb. Figure 2-1 is a graph of the phase of the 900 hybrid formed by the tandem 8. 3db couplers. A total phase of the tandem 8. 3db couplers varies from a high of 94 to a low of 65 but has a majority of the values near the average of 83. Figure 2-2 is a graph of the phase shift through the totalbalun system consisting of the tandem couplers and the 90 phase shifter. The maximum phase shift between the two arms of the 4

1084-4-Q 95 90 85 80 75 70, 65 60 55 50 45 j I I I I I.4.6.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 3.2 Frequency (GHz) FIG. 2-1: Phase Angle Between Output Terminals of Tandem 8.3 db Couplers. 5

1084-4-Q 190 180 170 150 140 I.4.6.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 3.2 Frequency (GHz) FIG. 2-2: Phase Angle Between Output Terminals of the Stripline Balun. 6

1084-4-Q output is 1910 with a minimum value being 1560. Average value of the phase shifter across the band is 1750 which reflects the fact that the tandem couplers do not have a true 900 phase shift. The phase in this case was measured by terminating the line with a 10db precision load in front of the connection to a tee while the second terminal was connected to a 50 Q2 load. Table 2-1 is a measure of the output power of the two balanced outputs from the balun system. In this measurement one of the balanced outputs was taken at a reference and the db ratio was taken of the second output. In this case the average unbalance between the two ports is 0. 34db with a maximum deviation between the ports of 0. 9db. A reflectometer was used to measure the reflection coefficient of the assembled balun with the matched outputs terminated in 50 Q loads. The 50 Q loads were then removed and the balun system outputs were coupled to the windings of a cavity backed bifilar spiral and the reflection coefficient was again measured across the band. The reflection coefficient did show an increase when coupled to the cavity backed spiral but it was not as severe as we had earlier expected as the VSWR remained well below 3:1. Oscillations of the reflection coefficient increased with frequency but did not show the erratic variations that were expected. Unfortunately the remaining time does not permit the checking of the phase and amplitude of the balun across the frequency band with mismatched terminations such as found with the spiral antenna which typically has a balanced impedance of 150 fQ between elements. Feeding the antenna with 50 Q stripline baluns would give a 1. 5:1 mismatch at each terminal. Patterns for a cavity backed spiral with a stripline balun were collected over a 3:1 band from 1 to 3 GHz. These patterns indicated an improvement over a similar spiral with a modified Duncan-Minerva balun. The patterns were taken for two linear orthogonal polarizations. More patterns are required to check the axial symmetry 7

1084-4-Q of an antenna with a stripline balun. However, the patterns apparently show some moding still existing in the cavity backed spiral at the higher frequencies. It was not expected that the stripline balun would stop this moding as this is a property of the antenna geometry and not a problem in the feed amplitude and phase.

1084-4-Q TABLE 2-1 Relative Power Division of Balun Frequency Ratio of Terminal Ratio of Terminal (GHz) Voltages (Per cent) Power (db) 1.0 97.2.24 1.1 95.2.43 1.2 96.8.28 1.3 95.2.43 1.4 96.8.28 1.5 95.2.43 1.6 95.6.39 1.7 90.0.92 1.8 93.6.58 1.9 92.4.68 2.0 94.0.54 2.2 96.4.32 2.4 101.6 -.14 2.6 105.6 -.47 2.8 98.8.10 3.0 94.8.46

1084-4-Q ELECTROMECHANICAL SWITCH The electromechanical switch consists of two parts; first, the drive unit, and second the switch junctions. The drive unit consists of a 1/8 horsepower Bodine motor, drive pulley, multiple gear reduction assembly, and a precision spindle. The drive motor and belt drive assembly provide the necessary driving power and speed for the system. The multiple gear reduction assembly provides several choices of switching speeds that range from 1000 rpm to 1 rpm (10 steps). The multiple gear reduction unit has been purchased from Geartronics and is a medium duty (model 2600 series system that is rugged enough to provide the necessary drive to the switch rotor. The precision spindle has been purchased from Gilman. The spindle has negligible end play and less than 0. 001 inch run out. (These specifications are important to ensure the 0. 004 inch spacing required between the rotor and stator of the switch Additional expense was incurred in the purchase of the spindle since pre-loaded bearings were placed both in the forward and rear section of the spindle to minimize run out in the spindle. The spindle also has a fine adjustment that will aid in adjusting the spacing between the switch stator and rotor. The electrical portion of the electromehcanical switch consists of two items: one, the capacitive coupling ports (17 inputs and 1 output), and two, a transmission line which is to be fabricated from stripline and will interconnect the switching port to the rotary joint, A photograph of a switching port is shown in Fig. 3-1. These are engineering models that were used to determine the final electrical characteristics of the capacitive coupled ports. VSWR data has been obtained over a 5:1 frequency band (0. 6 to 3. 0 GHz), and is shown in Fig. 3-2. It will be observed that the VSWR of the switch is less than 2:1 in the frequency range of 0. 6 GHz to slightly above 2. 8 GHz. 10

1084-4-Q FIG. 3-1: Engineering Models of Capacitive Junction of Electromechanical Switch. 11

3.0 2. 5 2.O0 I.tO I 1,5 1. 0 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 Frequency (GHz) FIG. 3-2: VSWR of a Single Switch Terminal.

1 084-4-Q The VSWR increases to as high as 2. 5 at 3. 0 GHz. It is conceivable that slight improvements in the VSWR characteristics of the switch could be achieved. However, in the interests of time and costs, it was felt that the present configuration shbould be accepted. It will be observed that the switching ports operate well over more than a 4:1 frequency band having a VSWR characteristic of less than 2:1. A sketch of the switch capacity junction is shown in Fig. 3-3. It is to be noted that this sketch is not to scale as is obvious when one considers that the center conductor of the coaxial connector has a dimension of 0. 080" and the spacing of the capacitive coupling is 0. 040". To aid in understanding the operation of the switch one may make an analysis employing transmission line techniques. For the present switch, coaxial connectors are located at the input and output of the capacitive junction, and have a nominal impedance of 50 2. The Rexolite region of the switch has a nominal impedance of 100 Q. The equivalent circuit for the switch is shown in the lower right hand corner of Fig. 3-3. The two inductances are obtained from the Rexolite sections of the switch. The capacitive portion of the switch is obtained between the two metalic discs which are 0. 375" in diameter and are spaced 0. 040" apart. Since the 100 Q sections of coaxial line are electrically short (less than 1/16 X) at all frequencies of interest, one may plot the impedance characteristics on an impedance chart (e. g., a Smith chart) and determine the inductive reactance as a function of frequency. However, in the case of the capacitive reactance, it is somewhat more difficult (at microwave frequencies) to determine the manner in which the reactance varies as a function of frequency. One of the reasons for the capacitive reactance to be more complicated is because the voltage is not uniformly distributed between the plates, but rather is restricted near the outer edges of the plates due to the skin effect. Because the voltage has a non-uniform distribution and further because this distribution changes as 13

1084-4-Q ~Output z ~ Teflon Output Rexolite 2200 a r t Metal - 1. 125" Dia............ -- -0. 375" Dia.. - FIG. 3-3' Sketch of Sw itch Capacitive Junction (Not to Scale)..... 14...............

1084-4-Q a function of frequency, the capacitive reactance varies in a non-linear fashion as a function of frequency. To obtain some insight as to the way the capacitive reactance behaves as a function of frequency, a special capacitive junction was fabricated. The capacitive junction was constructed by employing a 50 Q transmission line and tapering the inner and outer conductors as shown in Fig. 3-4 in such a manner as to obtain the desired capacitive plate diameters while maintaining the 50 Q2 transmission line characteristic. Employing this configuration (that of Fig. 3-4), a set of impedance data was plotted and is shown at the top of Fig. 3-4 for the capacitive junction. Had the capacitance remained constant (as in the case at audio frequencies) one would expect the capacitance reactance to have varied in a linear fashion along the resistance impedance circle of one. Employing the data for the capacitive junction and normal transmission line techniques for determining the inductance of the switch, several graphical analyses were made of the capacitive junction to be employed in the electromechanical switch and four junction configurations were fabricated and evaluated further. The final choice (that shown in Fig. 3-3) was a result of this analysis and the VSWR characteristics of this junction are shown in Fig. 3-2. To minimize the design time of the electromechanical switch, all switching ports (18, 17 fixed and 1 rotary) are being fabricated the same and will have the dimensions shown in Fig. 3-3. A drawing of the switch is shown in Fig. 3-5, and an overall drawing of the switch is shown in Fig. 3-6. A photograph of the electromechanical switch and drive assembly is shown in Fig. 3-7. 15

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~.lZ~ GEi. Osn~RTt~O~j~ OQe WO41 IMINC. r M M S e I II - - C O. ME MEMt O D ov % FIG. 3-6: Drawing of Electromechanical Sitch Assembly. FIG. 3-6: Drawing of Electromechanical Switch Assembly.

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1084-4-Q IV COMPUTER AND PERIPHERAL EQUIPMENT The peak reading voltmeter, which is a key component in the signal processing system, has been received and has been modified. At the time of its delivery from the manufacturer, considerable re-wiring was necessary to make the peak reading voltmeter compatible with the computer and analog-to-digital converter. Modification of this wiring has been completed and the peak reading voltmeter has been installed in the cabinet with the computer and peripheral equipment. The whole system has been delivered to the Radiation Laboratory, but upon delivery the programmer discovered a defect in the program interrupt, i portion of the interfacing inside the computer). The interfacing section of the computer has been returned to the supplier and is at the present being corrected. The remainder of the computer system and peripheral equipment has not been checked and will have to undergo further checking before final acceptance by the Radiation Laboratory. The program has been written for the computer and the computer will be programmed as soon as the interfacing is returned. 20

1084-4-Q V CONCLUSIONS The design of the 3db hybrid coupler has been completed and encouraging data has been collected both in regards to coupling and phase shift over a 5:1 frequency band. A stripline balun employing a 3db hybrid and a 90 phase shifter has been assembled and some preliminary pattern data collected from a bifilar cavity backed spiral. A set of drawings has been completed for the deliverable version of the electromechanical switch and the switch is now in the process of being fabricated. The necessary electromechanical parts have been received and are being prepared for assembly into the rotary switch. Preliminary data on the engineering model of the switch showed that a VSWR of less than 3:1 could be achieved over the 5:1 frequency band, and is less than 2:1 in the 600 MHz to 2.8 GHz range. The computer and peripheral equipment for the data processing equipment has been received and a program has been prepared. Some difficulty has been encountered with the interrupt circuit, however, this is now being corrected. 21

DISTRIBUTION LIST FOR REPORTS UNDER DAAB07-67-C0547 U of MI Projt2 01084 Destination Number of Copies Technical Library, Rm. 3E-1039, Pentagon Dir., Defense, Research and Engineering Washington, DC 20301 1 Defense Intelligence Agency ATTN: DIARD Washington, DC 20301 1 Director, National Security Agency ATTN: C31 Ft. George G. Meade, MD 20755 20 Naval Ships Systems Command ATTN: Technical Library 20526 Main Navy Bldg., Rm. 1528 Washington, DC 20325 1 Dir., U. S. Naval Research Laboratory ATTN: Code 2027 Washington, DC 20390 1 Rome Air Development Center ATTN: EMTLD, Documents Library Griffiss AFB, New York 13440 1 Electronic Systems Division, ESTI L. G. Hanscom Field Bedford, Mass. 07130 2 Hq, AFSC ATTN: SCTSE Bolling, AFB, DC 20332 1 CG, U. S. Army Materiel Command ATTN: R and D Directorate Washington, DC 20315 1 Redstone Scientific Information Center Attn: Chief, Document Section U. S. Army Missile Command Redstone Arsenal, Ala. 35809 1 CO, 52nd USASASOC Ft. Huachuca, Ariz. 85613 1 CO, Aberdeen Proving Ground Technical Library, Bldg. 313 Aberdean Proving Groun, MD 21005 1

U of M Project 01084 Distribution List (continued) CG, U. S. Army Combat Developments Command CDCMR-E Ft. Belvoir, VA 22060 1 CO, U. S. Army Combat Developments Command Communications-Electronics Agency Ft. Monmouth, NJ 07703 1 CO, U. S. Army Security Agency Combat Developments Activity Arlington Hall Station Arlington, VA 22212 1 U. S. Army Security Agency OAC of IS, DEV (IARD-EW) Arlington Hall Station Arlington, VA 22212 3 U. S. Army Security Agency Processing Center IAVAPC- R and D Vint Hill Farms Station Warrenton, VA 22186 1 CO, U. S. Army Nuclear Defense Laboratory Attn: Library Edgewood Arsenal, MD 21010 1 Harry Diamond Laboratories Attn Library Connecticut Ave and Van Ness St Washington, DC 20438 1 CG, U. S. Army Electronic Proving Ground Attn: Technical Information Center Ft. Huachuca, Ariz. 85613 1 Assistant Secretary of the Army R and D Department of The Army Attn: Deputy Assistant for Army R and D Washington, DC 20315 1 CO, U. S. Army Limited War Laboratory Aberdeen Proving Ground, MD 21005 1 CO, U. S. Foreign Science and Technology Center Attn: AMXST-RD-R, Munitions Bldg. Washington, DC 20315 1 Office, AC of S for Intelligence Department of the Army Attn: ACSI-DSRS Washington, DC 20310 1

U of M Project 01084 Distribution List (continued) CG, U. S. Army Electronics Command Attn: AMSEL-MR 225 South 18th Street Philadelphia, PA 19103 Director, Electronic Defense Laboratories Sylvania Electronic Products, Inc. ATTN: Documents Acquisition Librarian P.O. Box 205 Mountain View, Calif. 94040 Chief, Intelligence Materiel Develpmen t Office Electronic Warfare Lab., USAECOM Ft. Holabird, MD 21219 1 Chief, Missile Electronic Warfare Tech. Area EW Lab., USAECOM White Sands Missile Range, NM 88002 1 Chief, Willow Run Office CSTA Lab, USAECOM P. O. Box 618 Ann Arbor, MI 48107 1 HQ, U. S. Army Combat Developments Comm Attn: CDCLN-EL Ft. Belvoir, VA 22060 1 USAECOM Liaison Officer Aeronautical Systems, ASDL-9 Wright-Patterson AFB, Ohio 45433 1 USAECOM Liaison Office U. S. Army Electronic Proving Ground Ft. Huachuca, Ariz. 85613 1 CG, U. S. Army Electronics Command Ft. Monmouth, NJ 07703 ATTN: AMSEL-EW 1 AMSEL-IO-T 1 AMSEL-RD-MAT 1 AMSEL-RD-LNA 1 AMSEL-RD-LNJ 1 AMSEL-XL-D 1 AMSEL-NL-D 1 AMSEL-HL-CT-D 2 AMSEL-WL-S 6

U of M Project 01084 Distribution List (contminued NASA Scientific and Technical Info. Facility Attnr Aoquisistions Branch S-AK/DL P. O. Box 33 College Park, MD 20740 2 Battelle-Defender Info. Center Battelle Memorial Institute 505 King Avenue Columbus, 0. 43201 1 Remote Area Conflict Info. Center Battelle Memorial Institute 505 King Avenue Columbus, 0. 43201 1 TOTAL 75

Security Classification DOCUMENT CONTROL DATA- R&D (Security classification of title, body of abstract ancl indexing annotation must be entered when the overall report is classified) 1. ORIGINATIN G ACTIVITY (Corporate author).. a. REPORT SECURITY C LASSIFICATION The University of Michigan, Radiation Laboratory UNCLASSIFIED Dept. of Electrical Engineering, 201 Catherine Street, 2b GROUP Ann Arbor, Michigan 48108 NA 3. REPORT TITLE AZIMUTH AND ELEVATION DIRECTION FINDER TECHNIQUES 4. DESCRIPTIVE NOTES (Type of report and inclusive dates) Fourth Quarterly Report 1 April - 30 June 1968 S. AUTHOR(S) (Lost name, first name, initial) Joseph E. Ferris and Wiley E. Zimmerman 6. REPORT QATI 7a TOTAL NO. OF PAGES.. NO. OF' REFS September 1968 21 8a. CONTRACT OR GRANT NO. "4. ORIGINATOR'S REPORT NUMBER(S) DA AB 0767C-0547 b. PROJECT NO 1084-4-Q 5A6 79191 D902 0511 c. 9b. OTHER REPORT NQ(9) (Any other numbera that may be assigned this report) d. E COM-0547 -4 10. A'VA ILABILITY/I!MITAT!ON NOTICES Each transmittal of this document outside the Department of Defense must have prior approval of CG, U. S. Army Electronics Command, Fort Monmouth, New Jersey, 07703, ATTN- AMSE T-WT,-S 11. SUPP..EMENTARY NOTES.I..PONSORING MILITARY ACT'IVITY U. S. Army Electronics Command AMSEL-WL-S?-:__......._________ Ft. Monmoualth N:,T Q7703 13. ABSTRACT During this reporting period all efforts have been directed towards the design and development of individual components. The components to be discussed are the broadband hybrids and phase shifters which may be employed with either bifilar or quadrafilar spirals and the electromechanical switch required for the azimuth - elevation direction finder. Typical experimental data is presented for engineering models of the above components. The data processing equipment has been received from the supplier and is now being evaluated and debugged. D D, JAN 64473 Security Classification

Security Classitication 14. LINK A LINK B LINK C KEY WORDS ROLE WT ROLE WT ROLE WT Azimuth Elevation Direction Finder Broadband Directional Coupler Broadband Phase Shifter Quadrafilar Spiral INSTRUCTIONS 1. ORIGINATING ACTIVITY: Enter the name and address imposed by security classification, using standard statements of the contractor, subcontractor, grantee, Department of De- such as: fense activity or other organization (corporate author) issuing (1) "Qualified requesters may obtain copies of this the report. report from DDC." 2a. REPORT SECURITY CLASSIFICATION: Enter the over2a..REPORT SECUITY CLASSIFICATION: Enter the over- (2) "Foreign announcement and dissemination of this all security classification of the report. Indicate whether "'Restricted Data" is included. Marking is to be in accordance with appropriate security regulations. (3) "U. S. Government agencies may obtain copies of this report directly from DDC. Other qualified DDC 2b. GROUP: Automatic downgrading is specified in DoD Di-users shall request through rective 5200. 10 and Armed Forces Industrial Manual. Enter the group number. Also, when applicable, show that optional." markings have been used for Group 3 and (group 4 as author- (4) "U. S. military agencies may obtain copies of this ized. report directly from DDC. Other qualified users 3. REPORT TITLE: Enter the complete report title in all shall request through capital letters. Titles in all cases should be unclassified.,, If a meaningful title cannot be selected without classification, show title classification in all capitals in parenthesis (5) "All distribution of this report is controlled. Qualimmediately following the title. ified DDC users shall request through 4. DESCRIPTIVE NOTES: If appropriate, enter the type of __ it report, e.g., interim, progress, summary, annual, or final. If the report has been furnished to the Office of Technical Give the inclusive dates when a specific reporting period is Services, Department of Commerce, for sale to the public, indicovered. cate this fact and enter the price, if known. 5. AUTHOR(S): Enter the name(s) of author(s) as shown on 11. SUPPLEMENTARY NOTES: Use for additional explanaor in the report. Enter last name, first name, middle initial. tory notes. If military, show rank and branch of service. The name of the principal a-.thor is an absolute minimum requirement. 12. SPONSORING MILITARY ACTIVITY: Enter the name of the departmental project office or laboratory sponsoring (pay6. REPORT DAT —I Enter the date of the report as day, ing for) the research and development. Include address. month, year; or month, year. If more than one date appears on the report, use date of publication. 13. ABSTRACT: Enter an abstract giving a brief and factual summary of the document indicative of the report, even though 7a TOTAL NUMBER OF PAGES: The total page count it may also appear elsewhere in the body of the technical reshould follow normal pagination procedures, i.e., enter th be should follow normal pagination procedures, i.e., enter the port. If additional space is required, a continuation sheet shall number of pages containing informationbe attached. 7b. NUMBER OF REFERENCES.: Enter the total number of It is highly desirable that the abstract of classified reports references cited in the report. be unclassified. Each paragraph of the abstract shall end with 8a. CONTRACT OR GRANT NUMBER: If appropriate, enter an indication of the military security classification of the inthe applicable number of the contract or grant under which formation in the paragraph, represented as (TS), (S), (C), or (U). the report was written There is no limitation on the length of the abstract. How8b, 8c, & 8d. PROJECT NUMBER: Enter the appropriate ever, the suggested length is from 150 to 225 words. military department identification, such as project number, 14. KEY WORDS: Key words are technically meaningful terms subproject number, system numbers, task number, etc. or short phrases that characterize a report and may be used as 9a. ORIGINATOR'S REPORT NUMBER(S): Enter the offi- index entries for cataloging the report. Key words must be cial report number by which the document will be identified selected so that no security classification is required. Identiand controlled by the originating activity. This number must fiers, such as equipment model designation, trade name, military be unique to this report. project code name, geographic location, may be used as key 9b. OTHER REPORT NUMBER(S): If the report has been words but will be followed by an indication of technical conassigned any other repcrt 1Igumbers (either by the originator text. The assignment of links, rules, and weights is optional. or by the sponsor), also enter this number(s),. 10. AVAILABILITY/LIMITATION NOTICES: Enter any lim- itations on further dissemination of the report, other than those Security Classification

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