FR2656741A1 - BROADBAND DIPLEXER, IN PARTICULAR FOR DECAMETRIC WAVES. - Google Patents

Abstract

The object of the invention is to make it possible to benefit from the advantages of multichannel antennas when such an antenna is coupled to two transmitters by the same diplexer. For this, the length of the line sections (L1-L4, L1'-L4 ') of the diplexer can be modified by means of switches (C1, C2, C1', C2 ') whose pads are arranged in series in the sections. line of the diplexer. Application, in particular, to HF diplexers.

Description

Broadband diplexer, especially for

HF.

  The present invention relates to a diplexer for a broadband antenna and, in particular, for an antenna

  operating on HF, that is to say, frequencies

these range from 3 to 30 M Hz.

  In broadcasting, to transmit the same

  gram on two frequencies of neighboring channels and with the same

  my radiation characteristics, in order to be sure of reaching a given geographical area, it is known to use a diplexer which realizes the paralleling of two transmitters on the same antenna while avoiding, or at least rendering

  very weak, the coupling between the two transmitters.

  The currently used diplexers are designed to perform diplexing on two given channels at a given frequency in each channel.

  band, "multichannel", developed for more than ten years

  therefore much of their interest if they are used with

such diplexers.

  The object of the present invention is to avoid this inconvenience.

  come by giving the possibility of using the same diplexer for different transmission frequencies of the two transmitters which

  will therefore require the use of a multi-band broadband antenna

nal ".

  This is achieved thanks to a diplexer whose length

  the line elements that compose it, is adjustable.

  According to the invention, it is proposed to make a diplexer for coupling in parallel two transmitters to one and the same

  broadband antenna, with three access points

  connection between the two transmitters and the antenna and, between each transmitter port and the antenna port, a line with two separate connection points and, bypass, from the two connection points, respectively, two line segments, characterized in that it comprises first adjustment means for adjusting the position of each connection point in the line where it is located and second adjustment means for adjusting the length of each line section

in derivation.

  The present invention will be better understood and others

  characteristics will appear from the description below.

  FIG. 1 is a diagram of a diplexer according to the prior art, FIGS. 2 and 3 are diagrams of diplexers according to the invention, FIG. another diplexer according to the invention.

  In the different figures, the corresponding elements

  In addition, it should be noted that, for problems of space and readability,

  proportions have not always been respected in the figures.

  FIG. 1 is a schematic view showing a diplexer according to the prior art which receives signals at two distinct frequencies F and F 'respectively on a first and

  a second access, Ai, A 2, and delivers them to a branch antenna A

  on a third access AO In the described example F is

  higher than F ', so that in what follows and in the claims

  cations F and F 'will be called high frequency and low frequency respectively and the frequencies around F and F' will be

  respectively called high frequencies and low frequencies.

  The access Ai receiving the signal at the frequency F is connected to the access AO on which the antenna A is connected by a line which two distinct connection points M and N separate into three sections of line: a section L connects the point M at the access Ai, a section L1 connects the points M and N and a section L 2 connects the point N to the access AO Moreover, two line sections L 3, LA, arranged in a branch, respectively connect the

points M and N to ground.

  Similarly, the access A 2 receiving the signal at the frequency F 'is connected to the access AO by a line which two distinct connection points M' and N 'separate into three line sections: a section L' connects the point M 'at the access A 2, a section Li' connects the points M 'and N' and a section L 2 'connects the point N' A antenna access, AO; in addition two sections of line L 3 ',

  L 4 'respectively connect the points M' and N 'to ground.

  The diplexer according to FIG. 1 comprises a diplexer proper constituted by the sections of line

  L 2, AL 4, L 2 ', L 4' The lengths of these sections are respectively

  λ / 4, λ / 2, λ / 4, / 2, where X and A 'are the wavelengths corresponding to F and F'; these values are theoretical values but the real values are very similar. The diplexer according to FIG. 1 also comprises two impedance matching circuits formed respectively by the sections L 1, L 3 and LI ', L 3'. For example, on the low frequency channel, the introduction, in particular N ', line section L 4' causes a mismatch; to readapt the antenna A with its line L 4 ', at the nominal impedance, it is necessary to place in M' the short-circuited line L 3 'The length of the section L 3' is very close to that of the section L 4 'and therefore of / 2; the length of the section L 1 'depends on the antenna impedance, seen at N' and the line impedance of L 2 'Similarly, in the matching circuit formed by the sections L 1 and L 3, the line section L 3 has a length of the order of λ / 2 and the length of L 1 depends on the antenna impedance

  view of N and the line impedance of L 2.

  It is also known to use diplexers corresponding substantially, from the point of view of the lengths of the line sections, to the diplexer according to FIG. 1, but in which the line sections L 3, L 4, L 3 ', L 4 are no longer short-circuited at one end but are open at this end; it is also known to use diplexers in which one of the two channels, for example the low frequency channel, has short-circuited lines while the other channel has open lines. It should be noted that, generally, for lines o circulating high power, that is to say in the case of using transmitters of 100 k W and more, the diplexers

  open lines are not usually used in order to avoid

  radiation and corona problems; they can

  However, despite these disadvantages, when the ratio of the extreme frequencies of use is of the order

2 or greater than 2.

  A circuit, like that in Figure 1, can not function

  with two predetermined values respectively for

F and F '.

  FIG. 2 shows how the diplexer according to FIG. 1 can be modified to enable it to operate on four distinct values for its low frequency E 'and four

  distinct values for its high frequency F Figure 2 cor-

  to a study of a diplexer intended to be associated with a

  multi-channel, broadband antenna designed for the five broadband

  11, 13, 15, 17, 21 M Hz; the bandwidths are defined as follows according to international standards: band 11 M Hz = 11.65 to 12.05 M Hz = 3.43% of 11.65 band 13 M Hz = 13.6 to 13 , 8 M Hz = 1.47% of 13.6 band 15 M Hz = 15.1 to 15.6 M Hz = 3.31% of 15.1 band 17 M Hz = 17.55 to 17.9 M Hz = 1.99% of 17.55

  band 21 M Hz = 21.45 to 21.85 Mhz = 1.86% of 21.45.

  To be able to use all the possibilities of this

  antenna, the low frequency channel of the diplexer according to the

  gure 2 was designed to be able to couple to the antenna a transmitter

  in the 11, 13, 15 and 17 MHz bands, while the high-frequency flight was designed to couple to the antenna a transmitter working in the 13, 15, 17 and 21 MHz bands, allowing to operate the antenna in the following pairs of bands: 11-13, 1115, 11-17, 13-15, 13-17, 13-21, 15-17, 15-21 and 17-21; it should be noted that the pair 11-21 is not used because, the ratio of the frequencies between the two bands being very close to 2, it is difficult to prevent that harmonics 2 of the band of 11 M Hz do not

  disrupt the band of 21 M Hz.

  To enable these different operations, the diplexer of FIG. 2 comprises the same sections of line

  L, L ', L1, LM', L2, L2 ', L3, L3', L4, L4 ', that that of the

  1, in a similar arrangement, but the length of the line sections can be modified so that the diplexer can be adjusted according to the frequencies F and F 'indicated above. For this purpose, the low frequency channel, that is, that is to say in the path that leads the frequency signal F 'to the antenna A, and the high frequency path each comprise two switches: C1, C 2 for the high frequency path, Ci', C 2 'for the low path frequencies Each switch is a

  two-plate rotary switch with four pads per

  such as plots P 1 to P 14 and P 15 to P 18 for the first

  first and second slab of the switch C1; each slab is associated with a slider, such as cursors JIl and J 12 for the

  switch Cl, which correspond to the cakes respectively bearing

  Plugs P1 to P14 and P15 to P18 are used. The first of the two slabs of each switch has its pads in the connection between

  the two accesses Ai, A 2, and the successive pads of each

  first galette are interconnected by sections of line; thus the pads P1 to P14 of the switch C1 are in series in this connection, thanks to line sections K 11, K 12 and K 13 which respectively connect the pads Pli and P 12, P 12 and P 13, P 13 and P 14 The second of the two wafers of each switch has its successive pads connected by sections of lines; so

  the pads P 15 to P 18 of the switch C1 are connected by sections

  K 16, K 15, K 14 placed respectively between the pads P 15

  and P 16, P 16 and P 17, P 17 and P 18.

  The slider of the first wafer, such as the slider J 1 l of the switch Ci, is connected to one of the two end pads of the second wafer while the other end pad and the slider of this wafer are connected to the ground. line relative to the switch C 2, as well as the sliders and pads of this switch, have been designated in Figure 2 by adding 10 to the figure of the corresponding element relating to the switch C1, this is how the section K 22 of the switch C 2 corresponds to the section K 12 of the switch C1. Furthermore, to facilitate the understanding of FIG. 2, as well as

  that of Figure 3, the line sections of the first rollers

  tes, that is to say sections such as K 21, which are in

  between Al, A 2, have been drawn in the form of ar-

  rounded while the sections of the second pancakes of the

  were drawn in the form of slots.

  In the position they occupy in FIG. 2, the four sliders of the high frequency channel determine a structure according to FIG. 1, in which the points M and N are the mobile ends of the sliders of the first wafers of the switches C1 and C2. and wherein the line sections L1, L2, M3, IA of Figure 1 are respectively constituted by

  the sections going from the pad P 13 to the pad P 23, the pad P 23 to the ac-

  that AO, from the pad P 13 to the ground including the section K 14, and the pad P 23 to the ground including the section K 24 The position occupied by the sliders of the switches C1 and C 2 is that which is provided when the signal E ', on the access A 2, is in the

  band of 15 M Hz By moving the four sliders of the

  mutators Cl and C 2 simultaneously a pad on the right (in the sense of a displacement in Figure 2), or a pad on the left, or two pads on the left, the diplexer is set for a signal on access A 2 whose frequency F '

  is respectively in the band of 17, 13 and it M Hz.

  Similar comments could be made

  relatively to the switches Cl ', C 2' of the low frequency channel

  these, which are identical to those of the high frequency path and whose pads patties are wired with sections of line whose only length is different from the

  high frequency channel It should be noted that the position of the

  the low frequency channel corresponds to a signal from

  work, on access Ai, located in the band of 17 M Hz, tan-

  say that a move of all the sliders of the switches

  Cl 'and C 2' of a pin to the left, or a pin to the right, or two pins to the right would correspond to a working signal, on the access Ai, located respectively in the

bands of 21, 15 and 13 M Hz.

  The lengths of the sections, such as K11 and K25, are determined by considering a diplexer according to FIG. 1 in which the position of the points M, N, M ', N' would be adjustable as a function of the operating bands and in which the length short-circuited sections L 3, L 4, L 3 ', LA' would also be adjustable. Thus four positions are defined for each of these points and four lengths for each short-circuited section; the length of sections such as Kll and K 25

  can then be determined by simple subtractions

  account of the line lengths that are, for example,

  ple, the cursor C1 of the switch Ci in series with the link going from this cursor to the pad P 18 of the second wafer of this same switch The lengths of the line sections between the two switches of the same channel are average lengths determined in function of the impedance of the antenna to

  the average frequency of the frequencies of use.

  For the sake of simplification, the conductive lines of the various figures attached have been represented by a single line, of course they are symmetrical lines, of the kind two-wire lines, or asymmetrical, of the kind of the coaxial lines. according to Figure 2 has been made in two-wire lines, which is to say that for

  Figure 2 should contain lines representing

  two parallel lines, double sliders to two

  parallel arms and double slabs to two superpopular sets

four plots each.

  FIG. 3 is a diagram of an embodiment of a diplexer according to the invention associated with a multichannel antenna, with a wide band, A, working in the bands of 13, 15, 17 and 21 MHz. in FIG. 2 but with three-stud slabs, only the marks relating to the antenna, A, and to the ports, AO, AI, A 2, have been marked so as not to overload the drawing and make it possible to indicate, the lon -

  in meters of different sections of line.

  In this embodiment the high frequency path, that is to say that corresponding to the access Ai, was designed to work in the bands of 15, 17 and 21 MHz, while the low frequency channel was designed to work in the

bands of 13, 15 and 17 M Hz.

  The length of the sections in series between the line of the access Ai and that of the access A 2 are respectively

  1 -1,6 2,16 0,5 0,8 3,46 4,21 0,56 0,7 1 -

  1.47 meters As for the four elements of diversion line they each comprise three sections of line in series; the length of these sections, from the sliders relative to the first slabs (that is to say the slabs relative to the sections in series between access Ai and A 2) is 6.92 1.5 and 1 meter in the high way frequencies and 8.42 1, 13 and

  1.45 meters in the low frequency channel.

  The diplexer which has served as an example for the embodiment according to FIG. 3 has the following characteristics: use of a multichannel input impedance antenna spread at 150 ohms and of ROS (wave ratio

  stationary, standing-wave ratio or SWR in the litera-

  angle) at most equal to 2, symmetrical lines 300 ohms

  decoupling between high and low frequency

  these at least 30 d B which, with transmitters of 500 k W, leaves at most 500 W in the decoupled way, value quite acceptable, which does not prevent the commissioning of the second emitter connected to the diplexer when the first

is already in operation.

  FIG. 4 shows a study of a switch of the type of the switch C1 of FIG. 2, when the line L 3 has its end in an open circuit and not to ground as on

  Figures 1 to 3 In this case the structure of the first

  lette, with its cursor Jll, remains unchanged By cons the second cake with its cursor J 21 is changed so that

  line sections K 14, R 15, K 16 have no electrical contact

  with the rest of the diplexer when not in use; for this purpose the second wafer comprises pads, Q11, Q12, Q13, with two distinct terminals and a cursor B with three branches Bi, B 2, B 3 each cut by an insulator Si, 52, 53; the cursor B allows to gather the two terminals of the stud

  Q11 or Q11, Q12 or Q11, Q12, Q13 or other pads

  a plot; this cursor moves as the cursor J 12 of Figure 2 between four positions and its positions are related to those that takes the cursor Jll of the first slab Thus, from the position they occupy in Figure 4, the sliders Jll and B can be moved together from one position to

  the right, one or two positions to the left,

  to change the setting of the diplexer according to the

  low frequency of operation chosen.

  The present invention is not limited to the examples described, it is thus in particular that it applies to the case of diplexers intended to operate on a number of bands different from three or four, both in high frequencies and low frequencies and possibly for a number of bands different in high frequencies from that in low frequencies; it is sufficient that the two switches of a channel have the

  number of positions corresponding to the number of bands

from the other flies.

  Similarly, it is possible, for example with two-wire lines to use sliding slider switches and even to control the movement of sliders by a motor controlled by the selected operating bands and results.

  measurements made on the diplexer In the case of

  gure 4, that is to say in the case of open-line diplexers

  the slippery slider loses its interest in

  the second pancake which relates to a line in circuit or-

  green, since the cursor must stop

  at the two terminals of the same pad.

he

Claims (4)

  1 Diplexer to couple in parallel two transmitters   broadband antenna (A) having three ports (AO, Ai, A 2) for respectively connecting the two transmitters and the antenna and, between each transmitter port (Ai, A 2) and the antenna port (AO), a line (L, L1, L2; L ', Li', L2 ') with two distinct connection points (M, N; M', N ') and, in deriving, from respectively the two connection points, two line sections (L 3, TA; L 3 ', L 4'), characterized in that it comprises first adjustment means (J 11, J 21) for adjust the position of each   connection point in the line where it is located and se-   conds means of adjustment (J 12, J 22; B) to adjust the length   of each branch line section.   2 Diplexer according to claim 1, characterized in that the first adjustment means are constituted, between each transmitter port (Ai, A 2) and the antenna port (AO), by two successive groups of N pads ( Pll-P 14, P 21-P 24), one is an integer at least equal to 2 and two cursors (J 11, J 21) associated respectively with the two groups, and whose movable ends constitute the two connection points ( M, N; M ', NI). 3 Diplexer according to Claim 1, characterized in that the second adjustment means consist, for each of at least two of the branch sections, by a group of successive m pads (P 15 -P 18; P 25 -P 28 ) om is   an integer at least equal to 2, disposed in the section of the derivative   considered, and by a cursor (J 12, J 22) allowing ground one of the m plots.   4 Diplexer according to claim 1, characterized in that the second adjustment means are constituted, for each of at least two of the bypass sections, by p pads (Qll, Q 12, Q 13), with positive integer p, two separate electrically separated terminals, arranged in series in the section of the   considered, and by a slider (B) to connect electricity only from 0 to p p pots.