FR2591805A1 - Device for deviating the angle of elevation of an array antenna and array antenna equipped with such a device - Google Patents

Abstract

The deviating device is intended for an array antenna with n (n a positive integer) columns of m (m an integer greater than 2) dipoles D1-D4. It includes n switching members K, assigned respectively to the n columns, in order to simultaneously effect p (p an integer greater than 2 and less than m+1) connections, identical from one member to the next, between the feed line of the column and all or some of the dipoles of the column, each of the p connections being different from the others. Application, in particular, to decametre-wave array antennas.

Description

I Angle deviation device

  site of a curtain antenna and curtain antenna equipped with such a device.

  The present invention relates to a device for deviating the firing angle in elevation of a curtain antenna and, more particularly, of an antenna formed by n (n integer greater than 1) identical columns of

minus three doublets.

  It is known to make such devices by using

  switching devices which make it possible not to keep in operation-

  only part of the surface of the curtain antenna by disconnecting, for example, the doublet columns from the right half of the antenna and the doublets from the top of the columns of the left half of the antenna. These

  devices have different drawbacks, in particular they require

  try a large number of switching devices; moreover the change of the firing angle in elevation, by a disconnection like that which was indicated above, does not allow any more the modification of the firing angle in azimuth of the antenna because there is more enough doublet columns

  to vary the firing angle in azimuth.

  The object of the present invention is to overcome these drawbacks or,

to say the least, reduce them.

  This is achieved by a deflection device performing, in

  particular, the same disconnections, or connections, on all the colon-

nes of doublets.

  According to the invention, a device for deviating the elevation angle of an antenna formed by n (n positive integer) columns of m (m integer greater than 2) doublets, is characterized in that the doublets of all the columns being distributed, identically, in p (p integer greater than 2 and less than m + 1) groups of dipoles connected respectively to p lines, it comprises n identical and controlled switching members connected,

  identically, respectively to the n columns, each organ comprises

  as long as, for this, a common access for the connection of the column supply line, p distribution access connected to the p lines and means for making, by switching, p connections between the common access and respectively i = 1 , 2 ..., p of the distribution accesses, these

  connections comprising an impedance transformer between the line cd'ali-

  mentation and the i lines connected to the i accesses when the characteristic impedance

  ristic equivalent to the i lines is different from the characteristic impedance

that from the power line.

  The present invention will be better understood and other features.

  ticks will appear using the description below and the figures

  reporting, which represent: - Figure 1, a curtain antenna capable of being fitted with a deflection device according to the invention, - Figure 2, a schematic view of part of a deflection device according to invention, connected to a part of the antenna of FIG. 1, - FIGS. 3 and 4 more detailed partial views of the deflection device intended for the antenna of FIG. 1, - FIG. 5, a view of a another deflection device according to the invention, - Figure 6, a partial, detailed view of one of the elements of the

figure 5.

  In the different figures the corresponding elements are

designated by the same references.

  FIG. 1 represents a vertical curtain antenna comprising: four columns of four horizontal half-wave dipoles, such as the column of dipoles Dl, D2, D3, D4, a reflector R formed by a sheet of horizontal wires and two masts MI, M2 which are used to support the doublets and the reflector. This antenna is intended to work from 3 to MHz for a carrier power of 500 kW; the first doublets, such as D1, of each column are at a distance from the ground equal to 0.5 times

  the wavelength corresponding to the central working frequency.

  The antenna according to FIG. 1 of the HR 4/4 / 0.5 type (that is to say of the curtain type of horizontal dipoles, H, with reflector, R, with 4 half dipoles per line, 4 dipoles per column and a height of the first doublets from the ground equal to 0.5 times the half wavelength

  operating average) was chosen to be fitted with a device

  tif of deflection of firing angle in elevation according to the invention; the part of this device relating to the column of doublets Dl to D4 is shown on the

figure 2.

  FIG. 2 shows that the doublets D1 to D4 form three groups supplied respectively by three distinct lines L1, L2, L3. The line L1, of characteristic impedance Zo, feeds a first group formed by the doublets D1, D2; line L2, of characteristic impedance 2Zo, feeds the second group formed by the single doublet D3 and line L3, also of characteristic impedance 2Zo, feeds the third group

  formed of the single D4 doublet. Lines LI, L2, L3 end respectively

  vement distribution ports constituted by the terminals la, 2 and 3 of a switching member, K, which has eight terminals, la, lb, 2-7, and fixed or mobile links between some of these terminals. These connections are intended to allow the supply, either of the single line L1, or of the lines LI and L2, or of the lines LI, L2 and L3, by means of a supply line E of characteristic impedance Zo, leading to the 'access

common that constitutes terminal 7.

  Terminal 7 is coupled to a mobile arm which, by pivoting, can take three positions represented respectively by a series of crosses, by a series of lines and by a series of points; similarly terminal 2 is coupled to two mobile arms which, by pivoting, can each take three positions also represented by sequences of crosses,

lines and dots.

  The three movable arms are mechanically linked in such a way that they can only take simultaneously the three positions marked with crosses, or those marked with lines, or those marked

with dots.

  Terminals la and lb are connected by a very short line, H,

  of uniform characteristic impedance Zo.

  In the first position, marked with crosses, terminal 7 is connected to terminal 1b and terminal 1a is not connected to terminal 2 so that

  only the line LI and, therefore, the doublets DI and D2 are supplied.

  In the second position, marked by lines, terminal 7 is connected to terminal 5 and terminal 2 to terminals la and 4. As, between terminals 4 and 5, an impedance transformer, TI, establishes a fixed link , lines LI and L2 and, therefore, doublets Di, D2 and D3 are supplied

259 1805-

  while doublet D4 is not supplied. The impedance transformer T I is a broadband transformer, intended to ensure the impedance matching between the line E of characteristic impedance Zo and the lines LI, L2, of respective characteristic impedances Zo and 2Zo. As the lines LI and L2 are supplied in parallel, they correspond to an i. . '., ........ Zox2Zo 2Zo

  single line, characteristic impedance ZoZ- 2Z3; the transforma-

Zo + 2Zo - 3

  It is therefore planned to transform from 3 to Zo.

  In the third position, marked with dots, terminal 7 is connected to terminal 6 and terminal 2 to terminals la and 3. As between terminals 3 and 6, an impedance transformer, T2, establishes a fixed link , the three lines LI, L2, L3 and, therefore, the four doublets are supplied. The T2 transformer is also a large impedance transformer

  strip, intended to ensure the impedance adaptation between the line E of impe

  characteristic dance Zo and the lines LI, L2, L3 of characteristic impedances

  respective ticks Zo, 2Zo and 2Zo. As lines LI, L2, L3 are

  supplied in parallel, they correspond to a single line, of impe

  characteristic dance Z ox2Zox2Zo Z Z- transforma-

Zox2Zo4Zox2Zo + 2Zox2Zo l a

  Tor T2 is therefore planned to ensure the transformatioh from Z- to Zo.

  The device for deviating the firing angle in elevation, from the antenna according to FIG. 1, comprises, in addition to the switching member K, relating to the column of doublets D1 to D4, three other switching members identical to K, associated respectively with the three other doublet columns and connected identically on the one hand to a supply line

  and on the other hand to the doublets of the column with which they are associated.

  FIG. 3 is a schematic view showing half of the device for deviating the firing angle in elevation and the entire device for deviating the firing angle in azimuth of the antenna of FIG. 1. The deviating device the firing angle in azimuth is constituted, in a conventional manner, by a circuit with adjustable phase shifts, P, which is connected on the one hand to a line, Eo, of general supply of the antenna and on the other hand with four lines whose phase shifts with respect to the Eo line are individually adjustable. These four lines are respectively connected to the four switching devices which have been discussed above and which

  constitute the device for deviating the firing angle in elevation of the antenna.

  Only two of these organs have been represented, it is the organ K located at the foot of the column of doublets Dl to D4 of FIG. I and the organ K ', identical to the organ K and located at foot of the next column; the two other members, also identical to member K, have been indicated only by their respective references, K "and K" 'noted at the level of the line, leading to circuit P, to which they are connected. These four members are controlled simultaneously and identically by an electromechanical control assembly, S, represented schematically by a simple rectangle; this control assembly acts simultaneously on each of the axes of each of the switching members. The set of electromechanical control o10 S is not shown in detail because it would not add anything to the understanding of the invention and because this set, the production of which is part of the current remote control technique, can possibly be replaced by

manual control.

  Figure 4 shows the member K of Figures 2 and 3 and the conductors which lead to this member. While in Figures 2 and 3 the connections are shown by a single line, in Figure 4 the two conductors of each connection are shown. The member K comprises, in a parallelepiped metal box B represented as if it were transparent, three double arms, GI, G2, G, independent, articulated respectively around three axes AI, A2, A3; these axes are maintained on the one hand at the level of the wall of the box and on the other hand, towards the center of the box, by a support bracket, S. The different terminals la, lb, 2-7, of the member K are carried by the wall of the housing B. The double arms GI and G2 constitute the mobile arms of two double switches with two positions whose common terminals are

  connected by a cursor to the double terminal 2 on which the line L2 terminates.

  The movable arms make it possible to connect the terminal 2 respectively to the double terminals 3 or 4 and 4 or it being understood that the two movable arms

  must not be simultaneously on terminal 4.

  The axes AI and A2 are controlled so that the movable arms Gl, G2 connect terminal 2 either to terminals 3 and 4, or to terminals 4 and la, or to terminals 3 and la. The double terminal LI leads to it and a very short line, H, of uniform characteristic impedance Zo. On the double terminal 3 lead the line L3 and the impedance transformer

259 1805

  T2, consisting of a non-uniform symmetrical line which ensures the transformation of broadband impedance from Z2 to Zo. The double terminal 4 leads to the impedance transformer T1, also constituted by a non-uniform symmetrical line which ensures the transformation of wideband impedance from 2Zo to Zo. The double arm G constitutes the mobile arm of a three-position double switch which is coupled, by a double cursor, to terminal 7 on which the supply line E terminates. By action on axis A3 the arm G can connect the terminal 7 to Pl 'one of the double terminals 1b, 5 and 6. The connection with the terminal 1b, where the line H terminates, is carried out when the arms GI and G2 are respectively on the terminals 3 and 4. The connection with the terminal 5 o terminates the transformer TI, is carried out when the arms GI and G2 are respectively on the terminals 4 and la. The connection with the terminal 6 o terminates the transformer T2, is carried out, as shown in FIG. 4, when the arms GI and G2 are respectively on the terminals 3 and la. The member K which has just been described with the aid of FIG. 4 and which is intended for the antenna of FIG. I has been designed for a carrier power of 500 = 125 kW and its dimensions are approximately 0 , 8 m high, by I m

wide and 0.8 m deep.

  With the antenna according to FIG. I equipped with the device for deviating the elevation angle described with the aid of FIGS. 2 to 4, the different elevation angles obtained are: with the dipoles D1 to D2, 10.5 with doublets DI to D3,

8.5 with doublets DI to D4.

  FIG. 5 is a diagram which represents a column of six half doublets, DI to D6, of an antenna provided with a device for deviating the firing angle in elevation, according to the invention; FIG. 5 also shows the part of this deflection device which relates to the

column Dl to D6.

  The doublets DI to D6 of FIG. 5 are divided into three groups supplied respectively by three distinct lines LI, L2, L3. Line À - 2Zo L1, of characteristic impedance - supplies a first group formed by doublets D1, D2 and D3; line L2, of characteristic impedance 2Zo, feeds the second group formed of the single doublet D4 and line L3, of characteristic impedance Zo, feeds the third group formed of doublets D5 and D6. The lines L1, L2, L3 lead respectively to the terminals la, 2 and 3 of a switching member, K, having a diagram identical to the diagram of the member K in FIG. 2. With the member K in FIG. 5 , according to the values of the characteristic impedances of lines LI to L3, the transformers TI and T2 necessary to carry out the adaptation of impedance with a supply line, E, of impedance

  characteristic 2Zo, are respectively provided to ensure trans-

Z2 to 2Z and Zo 2Zo training

2 3 3 3

  An antenna and a site angle deviation device referring to the diagram in FIG. 5, with a height, above the ground, of the first doublet of the antenna doublet columns equal to the corresponding wavelength at the central working frequency, the site angles obtained were: 9 with doublets DI to D3, 7.5 with doublets D1 to D4, with doublets DI to D6. In the site range deflection device which has been partially shown in FIG. 5, the switching members, such as K, have not been produced in the same way as those used with the antenna according to FIG. 1 and shown in Figure 4; figure 6

  shows this other embodiment of a switching device according to the invention

  tion. FIG. 6 shows, in a perspective view, how the switching member K of FIG. 5 was made. The member K comprises a metal box B shown as if it were transparent; this box has the shape of a prism with a cross section constituted by a large equilateral triangle, truncated, according to the same small equilateral triangle, at each of its three vertices. The different terminals, la, lb, 2-7, of organ K

  are carried by the wall of the box.

  The member K comprises, inside the box, three double arms, G ', G ", G, mobile, mounted on an insulating axis, common, A, arranged on the right, not shown, which connects the midpoints of the prism bases. The double arms G 'and G "rotate in two same planes parallel to the bases of the e18o5 prism; they are 120 from one another and are secured to the axis A by means of hubs a1, a2 each comprising a disc situated outside the planes in which the arms G ′ and G ′ rotate; thus a fixed cursor, double, which rubs on the discs al and a2 makes it possible to connect the terminal 2 to the arms G ′ and G ″ without, as was the case with the sliders of the member according to FIG. 4, the arms abut on the sliders and therefore cannot do

a full turn around their axis.

  The double G arm, integral with two hubs a3, a4 each comprising a disc, can also make complete turns around the axis A without coming up against a fixed, double cursor, which, at one of its ends, rubs on the hub discs, and at the other end

  ends is connected to terminal 7.

  In Figure 6 the arms G ', G ", G are shown in the position where they respectively connect the terminals 4 and 2, la and 2, 5 and 7. By rotation of the axis A the arms G', G" and G can be brought into two other positions: a position where they connect terminals 3 and 2 respectively, la and 2, 6 and 7 and a position where they connect terminals 3 respectively

and2.4 and2, lbet7.

  The transformers T1 and T2 and the line H associated with the switching member K in FIG. 6 are respectively connected between the terminals 4 and 5, 3 and 6, la and lb. The present invention is not limited to the examples described, it is thus, in particular, that the invention can be applied in the case of curtain antennas comprising a single column or identical columns of three, five, seven doublets and even more; it is then necessary to associate with the doublet columns switching members which make it possible to vary in an identical manner, the number of doublets put into service in the

  columns, while inserting, when necessary, a device for adapting

  impedance between the doublet column and its supply line.

  In the case where the column has more than three doublets, the organ K could have more than three positions; for example with four doublets it can be envisaged to commission either one. either two, three, or four doublets. Except in special cases, the use of three-position K switching devices seems the most advantageous in view

259 1805

  the possibilities of varying the elevation angle and the cost of the switching members.

  It should be noted that the transformation ratio of the transforma-

  impedance values is calculated by considering, for a given position, the ratio between on the one hand the characteristic impedance equivalent to the impedance of the lines coupled to the input line and on the other hand the impedance

  characteristic of the centered line.

Claims (5)

  1. Device for deviating the elevation angle of a formed antenna   of n (n positive integer) columns of m (m integer greater than 2) doublets (DI-   D4; DI-D6), characterized in that the doublets of all the columns are distributed, in an identical manner, in p (p integer greater than 2 and less than m + l) groups of doublets connected respectively to p rows (LI, L2, L3), it comprises n switching members (K K ', KI ", K"') controlled identically and connected, identically, respectively to the n columns, each member comprising, for this purpose, a common access (7) for the connection of the supply line (E) of the column, p distribution access (la, 2, 3) connected to the p lines and means (AI, A2, A3, G, GI, G2, TI, T2 , H; A, G, G ', G ", TI, T2, H) to achieve; by switching, p connections between the common access and respectively i = 1, 2 ..., p of the distribution accesses, these connections comprising an impedance transformer (TI, T2) between the supply line (E) and the i lines connected to the i accesses when the characteristic impedance equivalent to the i lines is different   of the characteristic impedance of the supply line.   2. deflection device according to claim 1, in which p is equal to 3, characterized in that, in the connection corresponding to i = 1, the line (LI) which is connected, by means, to the common access (7) has the same   characteristic impedance (Zo; 2Zo) as the supply line.   3. deflection device according to claim 2, characterized in that the means comprise three double movable arms (GI, G2, G) mounted respectively in rotation about three distinct axes (AI, A2, A3), these arms each being able to occupy three distinct positions and the combinations of the positions of the three arms being limited to three: one o the supply line (E) is connected directly to only one (LI) of the p lines, one o the supply line is connected, to through a first impedance transformer (T1), with two (LI, L2), predetermined, of the p lines and one o the supply line is connected to the p lines through a   second impedance transformer (T2).   4. deflection device according to claim 2, characterized in that the means comprise three movable arms (G ', G ", G) mounted in 259 1805   Ill rotation around a common axis (A), this axis can take three   separate positions: one or the supply line (E) is directly connected   ment to only one (LI) of the p lines, one or the supply line is connected, through a first impedance transformer (TI), to two (LI, L2), predetermined, of the p lines and one o power line is   connected to the p lines through a second impedance transformer (T2).   5. Curtain antenna formed by n (n integer greater than 1) columns of m (m integer greater than 2) doublets (DI-D4; DI-D6), characterized in that it comprises p (p integer greater than 2 and less than m + l)   deviation according to any one of the preceding claims.