United States Patent (19) 11, 3,939,477 Green et al. (45) Feb. 17, 1976 54 QUADRUPOLE ADCOCK DIRECTION 3,824,596 7/1974 Guion et al......................... 343/19 FINDER AND ANTENNATHEREFOR FOREIGN PATENTS OR APPLICATIONS (75) Inventors: Terence C. Green; William G. 59 1867 9/1947 United Kingdom................. 34.311 19 Guion; Douglas N. Travers; William M. Sherrill, all of San Antonio, Tex. OTHER PUBLICATIONS Terman, Electronic and Radio Engineering, 4th Ed., (73) Assignee: Southwest Research Institute, San 1955, pp. 1050-1051. Antonio, Tex. Evans; “IRE Transactions on Antennas & Propaga 22) Filed: Apr. 6, 1973 tion'; Nov., 1962; pp. 686-691. 21 Appl. No.: 348,479 Primary Examiner-T. H. Tubbesing Assistant Examiner-S. C. Buczinski 52) U.S. C. ........ 343/113 R; 343/100 PE; 343/119 Attorney, Agent, or Firm-Donald Gunn 51 Int. C.’............................................ GOS 5/04 58 Field of Search........ 343/1 13 R, 1 19, 124, 799, 57 ABSTRACT 343/800, 100 PE A plurality of dipoles is arranged and connected to (56) References Cited form a quadrupole Adcock Antenna system which is connected with direction finding circuitry to define a UNITED STATES PATENTS direction finder system of which two embodiments are 2,953,782 9/1960 Byatt......... A 343/124 disclosed. The system responds to any transmitter to 3,329,954 7/1967 Travers............. ... 34311 13 R be located. 3,490,024 lf 1970 Sherrill et al. ... - - - - - - - 34311 13 R 3,727,227 4/1973 Takao et al..................... 34311 13 R 39 Claims, 14 Drawing Figures Zeuth U.S. Patent Feb. 17, 1976 Sheet 1 of 4 3,939,477 10 FIG. 1 12 15 18 N 19 11 17 02 1 3 12 13 OQY16 1 3 2. 27 20 - 21 7 5 4 ZEN/TH F/G.5 F/G. 6 PLANE NCIENCE F/G.7 U.S. Patent Feb. 17, 1976 Sheet 2 of 4 3,939,477 F/G. 8 | sin22 cos 22 sin Ø cos 2 F/G, 10 f761 ANTENNA SEQUENCING RELAYS Oo 5O a X - | TWIN CHANNEL w RECEIVER 7 53 / 55 51 52 5 ANTENNA 4 SPAC/NG LOGIC SENSE DETECTOR IF ANALOG DISPLAY A ND/OR COMPUTER SENSE U.S. Patent Feb. 17, 1976 Sheet 3 of 4 3,939,477 F/G, 12 sin 20 cos20 59 --- DRIVE MOTOR --- 60- RESOLVER ENERGIZE SINGLE CHANNEL RECEIVER 63 SWEEP ANALOG CIRCUIT AND/OR DISPLAY COMPUTER / A 56 64 -66 RF FIG. 13 - 65 SPST RF SEMSE SWITCH ENERGIZE RF QUADRATURE 67- MOTOR SUMMER 69 RF SINGLE 68) RESOLVER CHANNEL RECEIVER 71 IF 72 SWEEP CIRCUIT AND DISPLAY AND/OR COMPUTER U.S. Patent Feb. 17, 1976 Sheet 4 of 4 3,939,477 pi cos 2 F/G, 14 s in 20 3,939,477 1. 2 QUADRUPOLE ADCOCK DIRECTION FINDER DESCRIPTION OF THE DRAWINGS AND ANTENNATHEREFOR FIG. 1 is a perspective view of a first arrangement of dipole elements in a quadrupole Adcock antenna pat- . PRIOR ART tern arrangement, British Pat. No. 130,490, Adcock, Frank, Aug. 7, FIG. 2 is a perspective view of a second arrangement 1919. using twice the number of elements, thus obtaining Breuninger, H. W., “The Limits of Usefulness of the reduced spacing error at high frequencies; Adcock Direction Finder with 'N' Masts', Hoch: tech. FIG. 3 is a perspective view of an antenna arrange u. Elek: akus, vol. 59, pp. 50-57, February, 1942. 10 ment that can be on a ground plane; Redgment, P. G. Struszynski, W., and Phillips, G.J., FIG. 4 schematically shows the manner in which the "An Analysis of the Performance of Multi-Aerial Ad elements of FIG. 1, FIG. 2, and FIG. 3 are intercon cock Direction-Finding System,' JIEE, vol. 94, IIIA, nected; pp. 751–756, March, 1947. FIG. 5 defines the azimuth and incidence angles; British Pat. No. 498,417, Wagstaffe, C.F.A., July -15 FIG. 6 shows the azimuthal antenna pattern of a 1937. quadrupole Adcock antenna system; FIG. 7 shows the incidence plane of the antenna British patent application No. 29088/45, Wright, Sir pattern of a quadrupole Adcock antenna system; C. S., Redgment, P. G., and Rocke, A. F. L. FIG. 8 illustrates a quadrupole Adcock antenna sys SUMMARY OF THE INVENTION 20 tem providing both sine 2db and cosine 2db outputs; FIG. 9 schematically illustrates one manner of inter The invention herein described was made in the connection of the antenna system of FIG. 8; course of a contract with the Department of the Navy. FIG. 10 schematically represents a plan view of quad In direction finding systems, the quality of data is in rupole and dipole Adcock antennas arranged for use in large part dependent on the DF antenna characteris 25 a direction finder system; tics, i.e. pattern quality, apertures, directivity, and so FIG. 11 is a schematic block diagram of a direction on. Antenna patterns suitable for direction finding finding system utilizing the antenna system of FIG. 10; purposes are easily obtained in theory, but practical FIG. 12 is an alternative direction finding antenna problems arise which degrade the antenna pattern the system utilizing the antennas of FIG. 10; oretically given. For example, the antenna may be lo 30 FIG. 13 is an alternate direction finding system using cated near objects which cause re-radiation. Other only one quadrupole Adcock antenna and one dipole problems may arise in the implementation of a direc Adcock antenna which are rotated together; and tion finding system. The Adcock antenna is particularly FIG. 14 is an alternate direction finding antenna advantageous for use in a direction finding system. The system using only eight dipole elements arranged as Adcock antenna was first introduced in 1919, and has 35 shown in FIG. 8, for example, to obtain signals from the been substantially perfected since that time. This origi antenna which are a function of sin 2qb, cos 2db, sin (b nal Adcock antenna has an azimuthal response to verti and cos b. cal polarization which is characterized by two nulls, separated 180° from each other. The present invention DESCRIPTION OF THE PREFERRED has four nulls in the azimuthal response to vertical 40 EMBODIMENTS polarization which are separated 90° one from another. Attention is first directed to FIG. 1 showing a quad This property gives the present invention the name rupole Adcock antenna system 10 formed of a plurality "Quadrupole Adcock'. The original Adcock shall be of vertically oriented dipole elements. Four vertically distinguished as "Dipole Adcock'. arranged dipole elements are split and connected in the The present invention and the dipole Adcock have 45 manner of the quadrupole Adcock antenna system. similar properties which lead the present invention to The preferred locations of the dipole elements 11, 12, likewise be named Adcock. They are the use of dipole 13 and 14 are at the four points of an imaginary square elements and insensitivity to horizontally polarized in the horizontal plane. The eight outputs 1 through 8 of the four split dipoles are then combined in the man radiation. 50 ner shown in FIG. 4. The quadrupole Adcock antenna system which is In FIG. 2 a quadrupole Adcock antenna system 15 is formed of a plurality of appropriately connected in formed of eight vertical dipole elements. The upper vididual dipole elements is particularly advantageous halves 16, 17, 18, 19, 20, 21, 22, 23 of the eight dipoles over many DF antenna systems such as those utilizing are connected together in pairs 16 and 17, 18 and 19, loop elements. The polarization of the incident signal 55 20 and 21, 22 and 23 (preferably spaced 90° apart in may vary significantly dependent on the transmitter to azimuth) as are the lower halves 24 and 25, 26 and 27, the receiving antenna. Direction finding antennas using 28 and 29, 30 and 31. The eight outputs are also com loop elements have antenna patterns which vary with bined in the manner shown in FIG. 4. The eight ele the incident signal polarization. By contrast, the quad ment quadrupole Adcock has the advantage of reduced rupole Adcock antenna pattern on the other hand is 60 spacing error at the high frequency end of the spectrum polarization independent at least to the degree pro which is of interest for the antenna. vided in the conventional dipole Adcock. The arrangement of FIG. 3 illustrates the implemen The quadrupole Adcock antenna system of the pres tation of a quadrupole Adcock 32 on or relative to the ent invention preferably utilizes a number of dipole earth or other ground plane. This arrangement employs elements. The summations required by the intercon 65 four vertical antenna elements 33, 34, 35 and 36. The nection of various dipole elements can be utilized to image elements seen in the ground plane are connected obtain sine 2db or cosine 2db azimuth response data for to the horizontal conductors. The horizontal conduc use in a direction finding system. tors provide the necessary symmetry to cancel the pick 3,939,477 3 4 up of the horizontal component of the incident radia taught by the present invention and two dipole Adcock tion. The preferred locations of the four vertical ele antennas 53, 54. The quadrupole Adcocks are symboli ments are again at the four points of an imaginary cally represented in FIG. 10, rotated from one another square in the horizontal plane. The eight outputs are by 45 so as to respond to the sine and cosine of twice also combined in the manner shown in FIG. 4. The the azimuth angle of the target. Dipole Adcocks pro antenna system of FIG. 3 is advantageous in that the vide output signals which are a function of the sine and vertical elements are reduced in height by one-half.