JPH01243601A - Antenna feeder circuit - Google Patents

Abstract

PURPOSE:To electrically change the directional direction by using a feed circuit in which high-order mode generators, variable attenuators and coaxial waveguide convertors are combined. CONSTITUTION:The high-order mode generators 10a and 10b consisting of strip lines are provided on the over size waveguide 1 on the side of the antenna, and the coaxial waveguide converters 11a and 11b connected with a waveguide 3 which can carry only a basic mode on the side of a transmitter and a receiver, and the high-order mode generators 10a and 10b are connected with a coaxial cable 13 into which the variable attenuators 12a and 12b are inserted. When a part of power from the transmitter is fetched from the waveguide 3 and it is inputted to the high-order mode generators 10a and 10b at the time of transmission, for example, the mode of the strip lines in the over size waveguide 1 are excited. When the mode is synthesized with a TE11 mode, the maximum position of an electric field in the edge surface of the over size waveguide 1 moves from the center of the waveguide 3 to the side of a tube wall. Thus, the directional direction of the antenna can electrically be changed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a feeding circuit for an antenna that is used in the microwave band and millimeter wave band and is capable of changing the pointing direction.

[Conventional technology]

Figure 7 shows, for example, 2 of ``Satellite Communication Engineering'' by Kanken (1st edition published in June 1960, revised 1st edition published in 1971).
FIG. 5 is a schematic diagram showing an example of a conventional feeding circuit for an antenna whose pointing direction can be changed, as shown on pages 56 to 269; In the figure, ltl and tsl are the first
1 second circular waveguide, (2) is a tapered waveguide, (4) is a rectangular waveguide, (6) is a coupling hole, 161 I'i iris, (7) is a magic T, (81, (9+ are the H branch and E branch of Magic T (7), respectively. The first circular waveguide il+ is an oversized waveguide in which higher-order modes can propagate.

The diameter of the second circular waveguide (3) is selected so that it is a fundamental mode waveguide capable of propagating only the fundamental mode. 1st
The circular waveguide W +11 is connected to the horn, and the second circular waveguide (3) is used by being connected to a communication transmitter/receiver.

Next, the operation will be explained. When the pointing direction of the antenna deviates from the target object, the first circular waveguide +11 has a higher-order mode TM in addition to the fundamental mode TE11 mode.
o1 mode occurs. This TMo1 mode is coupled to the rectangular waveguide (4) via coupling holes (6) provided above and below the first circular waveguide ill, synthesized by the magic T (7), and then exits from the H branch (8). It can be taken out.

The TE11 mode is also coupled through the coupling hole (6), but this mode is synthesized by magic T and taken out to the E branch (9), and does not couple to the H branch (8). In this way, H
Only the TMQI mode is taken out from branch (8).

The iris (6) forms a band-pass filter that passes only the same wave number of the beacon in the case of satellite communication. H branch (8
) is input into a tracking receiver to obtain a tracking signal. The antenna can be mechanically driven in accordance with this tracking signal to correct the pointing direction.

[Problem to be solved by the invention]

However, in conventional antenna feeding circuits, a tracking receiver is required in addition to a communication transmitter/receiver in order to obtain a tracking signal from the extracted higher-order mode, which poses a problem in that it is expensive. Furthermore, since the antenna is mechanically driven based on the obtained tracking signal, there is a problem that the antenna device is large and heavy.

The present invention was made to solve these problems, and an object of the present invention is to provide an antenna feeding circuit that can electrically change the pointing direction.

Next [ill! [Means for Solving the Problem] The antenna feeding circuit according to the present invention provides a high-order mode generator composed of, for example, a strip line in an oversized waveguide on the antenna side, and generates a fundamental mode on the transmitter/receiver side. The coaxial waveguide converter coupled to the waveguide capable of propagation is connected to the above-mentioned higher-order mode generator by a coaxial cable inserted with a variable attenuator.

[Effect]

In this invention, for example, in the case of transmission, when a part of the power from the transmitter is taken out from the waveguide and inputted to a higher-order mode generator composed of a strip line, a strip line is inserted into the oversized waveguide. The modes of the line are excited. When this mode is combined with the TEo mode, it moves from the center of the waveguide toward the tube wall to the maximum position of the electric field at the end face of the oversized waveguide. Therefore, the pointing direction can be changed without mechanically rotating the antenna.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. ′#
FIG. S1 is a schematic perspective view of an antenna feeding circuit according to an embodiment of the present invention. In the figure, (108).

(10b) is a higher-order mode generator, (l1m)-(llb
) is coaxial guide, wave tube i exchange a, (12m)-(12b)
td variable attenuator, a attenuator is a coaxial cable, (11~
(3) is the same as in FIG. Higher-order mode generator (
10m) - (10b) is 18 around the circular waveguide ill.
Relative angle opposite position of 0°? It is set up so that In addition, the coaxial waveguide converters (11m) and (11b) are provided in the circular waveguide c# (31), and the above-mentioned higher-order mode generator (10m)-(10b) and the above-mentioned coaxial waveguide converter (l1
m), (llb) are variable attenuators (12a)-(12b)
) K is connected via coaxial cable 03i.

Figure 2 (,) is a partially cutaway schematic perspective view of the higher-order mode generator (10), and Figures (b) and (C) are lines 1B-IIB in Figure 2 (,), respectively. and nc-ti
This is a cross-sectional view taken along line c. In the figure, -6α5) are the @1 and second strip lines, respectively, p1 to D4 are diodes, α-kl through holes, αη are capacitors, and p is applied to the diode DI-D4. This is a terminal for bias voltage.

In the first strip line Q4), the strip conductor (18
a).

(18t+), in the second strip line aω, the strip conductors (19a) and (19b) constitute a coplanar line, and the strip conductors (18a) and (18b)
The coaxial line (inner conductor and outer conductor of one country are connected to each of the through holes (161) are strip conductors (18a) and (19g) and (18t+) and (19b) are connected to each other. Diodes D1 and D2 are provided at a position 174 wavelengths apart from the through hole αd at the operating frequency. Also, diodes D3@D4 are connected to both strip lines (141
# (Provided at the end on the circular waveguide side of +51.

The IJ tube lines H and 05) are provided on the front and back sides of the dielectric substrate, and the line length is 1/2 wavelength longer than the second IJ tube line α. . Figure 2 (
In , ), a ground conductor is provided between the IJ tube line color (151) to prevent coupling, but the same operation will occur even if no ground conductor is provided.

Next, the operation of this antenna feeding circuit will be explained in the case of transmission. As shown in Figure 81, the fundamental mode waveguide (
3) A part of the transmission power is transferred from the coaxial waveguide (!J!
1m) = (llb), variable attenuator C12m
).

(12b) to the higher-order mode generator (10g)-(1
0b). Higher-order mode generation & I Qos)e
In (10b), the diode Die D2 is provided at a position 1/4 wavelength from the through hole a0, so for example, if the diode D2 is made conductive (ON), the second strip line (151 is the through hole It becomes OPEN at the position of Hall α, and the power from the coaxial cable Q3 is transmitted to the strip line 04 of @1 without being affected by the second IJJ tube 051. Conversely, if diode DI is turned on, gIJl's) IJJ
The tube path (141 becomes 0PEN, and the power is transmitted to the second strip line α. In this way, the diode D
1. By turning D2 ON and OFF, the power to the strip line can be switched between the IJ tube color (I6) and the length of both strip lines (I (4) and 05). Since the wavelengths differ by /2, a phase difference of 180 @ can be given to the electric field at the end of the line. At this time, the diode D3. Set D4dOFF.

Figures 9 and 13 show the amplitude distribution of the electric field in the first circular waveguide +11.
(b) shows the case where the diode D1 is turned on and the signal is transmitted via the second strip line (14).

In the electric field width distribution diagram in Figure 3, the solid line is TEI l
mode, the broken line shows the higher-order mode of the first circular waveguide fi+ coupled from the IJJ tube path, and the dashed line shows the result of combining the TE11 mode and the higher-order mode. In addition, Figure @4 shows the boundary distribution of the fundamental mode and higher-order modes of the circular waveguide. The figure (,) is TE! 1 mode, same figure (b)
is a higher-order mode coupled from the strip line, and this can be considered to be a combination of the TMυ1 mode shown in FIG. 5(c) and the TE21 mode shown in FIG.

In Figure 9J13 (,), the first strip line (1
4 mode is coupled to the first circular waveguide 11+, the first
The position of the electric field maximum in the circular waveguide (1) moves from the position y-o to y-+y1. Also, in Fig. 3(b), y=-
Move to yl. Furthermore, a variable attenuator (12a), (
By adjusting 12b), the electric field strength on the strip line -99ω changes, the magnitude of yl can be continuously changed, and the peak power tti radiated from the horn can be changed.
'i can be changed to any position from +y1 to -yl on the y axis.

In the explanation so far, diode D3. D4 was set to OFF, but if the lower diode D3 of the higher-order mode generator (10m) and the upper diode D3 of the higher-order mode generator (10b) are turned ON while diode D2 i is ON, a circular conductor will be created. A higher-order mode as shown in FIG. 5(b) is excited within the wave tube (1). This mode is shown in Figure 5 (
It can be thought of as a combination of the TEo mode in c) and the TE21 mode in (d) of the same figure. In this case, unlike Figure @3, the maximum electric field position on the X axis moves. Contrary to the above explanation, the upper diode D3 of the higher-order mode generator (10m) and the lower diode D3 of the higher-order mode generator # (10b) are turned on, or the diode D3
is kept in the above-mentioned state, and if the diode DI is turned on, the maximum position of the electric field on the X-axis moves in the opposite direction. If you adjust the variable attenuator (12m)-(12b),
The maximum electric field position can be set at any position.

In this way, by turning off the diodes D1 to D4, the electric field of the first circular four-wave tube +11 can be positioned at its maximum.

On the other hand, in the case of reception, when the pointing direction of the antenna deviates from the target object, the TMQI mode, which is a higher order mode, exists in the first circular waveguide fil in addition to the TE11 mode.

TE21 mode and TEQ l mode occur. Among these, only the higher-order mode is generated by a higher-order mode generator (10a),
It is coupled to the strip line of (10b), converted to coaxial mode, and passed through variable attenuators (12a), (12b) and coaxial waveguide converters (l1m) (llb) (llb) to the circular waveguide ( 3).

Therefore, by adjusting the diode Di-D4 and the variable attenuator (12m) = (12b) in the same way as in the case of transmission, in order to maximize the reception level of the receiver, the directivity direction can be changed to the direction of the target. -Can be corrected.

Although the explanation up to now has been based on the transmission case, in actual operation, the diodes D1 to D4 . If you adjust the variable attenuators (12a) and (12b) to detect a deviation in the pointing direction and transmit while maintaining that state, you can maximize the power even if the object is located in a direction different from the front direction of the antenna. It can be transmitted to the target object.

Furthermore, if a digital attenuation device is used as the variable attenuators (12a) and (12b), switching of the diodes D1 to D4 and adjustment of the variable attenuators (12a) and (12b) can be performed using a digital computer. , can be set in advance.

FIG. 6 shows another embodiment of this invention, gS1
The same parts as in the figure are arranged every 90 degrees in the circumferential direction. In this case, the directional directions are orthogonal to each other.
ft can be modified. However, in this case, in order to reduce the coupling of cross-polarized waves, a higher-order mode generator (10a
) to (10d) must be an integral multiple of the IA wavelength.

In addition, in the above embodiment, if an amplifier is built into the variable attenuator, even if the output from the coaxial waveguide converter is small, a large amount of power can be input to the higher-order mode generator. The correction range of pointing direction can be increased. Furthermore, although the above embodiment describes the case where a circular waveguide is used, the present invention is not limited to this, and can also be applied to a case where a square waveguide is used.

〔Effect of the invention〕

As described above, according to the present invention, by using a feeding circuit that combines a high-order mode generator, a variable attenuator, and a coaxial waveguide converter, the directivity direction f of the antenna can be electrically adjusted.
! : Since the antenna can be changed, a mechanical drive device for the antenna is not required, and the antenna device can be made smaller and lighter. Furthermore, there is no need for a tracking receiver, which has the effect of reducing costs.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view showing an antenna feeding circuit according to an embodiment of the present invention, FIG. Figure 2 (b) # (C) is IIB in Figure (1), respectively.
-■B, ■C-■C cross-sectional view, Figure 3 is a diagram showing the interpupillary distance distribution of the electric field in the first circular waveguide in this example, @ Figure 4 and Figure 5 are respectively this FIG. 6 is a schematic perspective view showing another embodiment of the present invention; FIG. FIG. 7 is a schematic perspective view showing a conventional antenna feeding circuit. In the figure, (1) is the first waveguide, (2) is the tapered waveguide, (3) is the second waveguide, (10m) - (10b)
, (10c)-(10d) are higher-order mode generators, (l1
m)-(llb)-(llc). (lid)Vs, coaxial waveguide converter, (12m)-(1
2b)-(12c)-(12d) are variable attenuators, Q31
is a coaxial cable. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] (1) In an antenna feeding circuit that connects a communication transmitter or receiver and an antenna, a first
a second waveguide that is connected to the transmitter or receiver via a tapered waveguide to the first waveguide and propagates only the fundamental mode, and one end of which is connected to the first waveguide. a higher-order mode generating means coupled to the wave tube and capable of generating a higher-order mode in the first waveguide; and a coaxial cable having one end connected to the other end of the higher-order mode generating means. An antenna feeding circuit comprising: a coaxial waveguide converter whose end is coupled to the second waveguide; and a variable attenuator provided in the middle of the coaxial cable.