JP2002164732A - Antenna for satellite broadcasting - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve antenna performance. SOLUTION: A spacer (A) 3, a feeding aggregate line 4, a spacer (B) 5, a wave cap 6, a radio wave resonator 7, a circulator 8, and a spacer (C) 9 are successively housed in a back case 1, and the back case 1 is closed by a top cover 10, and an LNB 11 is mounted through a waveguide 2 on the surface side of the back case 1. Thus, it is possible to improve the flatness of the back case 1 which is also used as a reflector, and to suppress the loss of any resonance energy by insulation of the circulator 8 against the radio wave resonator 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a satellite broadcast for improving antenna performance by, for example, improving the flatness of a reflector or preventing energy loss in a radio wave resonator. Regarding antennas.

[0002]

2. Description of the Related Art A satellite dish antenna includes a parabolic antenna and a flat antenna. The parabolic antenna is configured to input a signal from a curved reflector to a waveguide window of the LNB. However, such a parabolic antenna is not suitable for miniaturization because it is necessary to increase the size of the reflector in order to input a 100% signal into the waveguide window of the LNB.

[0003] In this respect, the flat antenna has an advantage that a 100% signal can be input to the waveguide window of the LNB even if the size of the reflector is reduced.

[0004] An example of such a flat antenna is disclosed in Japanese Patent Application Laid-Open No. H11-17447. That is, as shown in FIG. 10, the flat antenna 11 includes a front panel 12 and a back panel 13.

[0005] The back panel 13 also serves as a reflection plate, and is formed by pressing a steel plate into a rectangular shape in plan view. At the substantially center of the back panel 13, a storage chamber 19 for the LNB 22 swelling downward in a rectangular box shape is formed. The housing 25 of the LNB 22 is formed by press-forming a steel plate, and a substrate 26 is horizontally mounted on the inside thereof. The substrate 26 includes a HEMT, an LNA (low noise amplifier), a band-pass filter, a local oscillation circuit, a mixer,
Various electronic circuits such as an F amplifier are mounted. Cup-shaped shield cases 27 and 28 are respectively mounted on the LNA through which the high-frequency signal flows and the local oscillation circuit.
Thereby, the leakage of the high-frequency signal is prevented.

A waveguide 29 is provided on one side of the LNB 22. The waveguide 29 is formed by die casting and screwed to the LNB 22. A dielectric spacer 35 is laid on the inner surface of the back panel 13, and an antenna substrate 36 is laid thereon. The dielectric spacer 35 is formed using an extremely thin styrene foam plate having a thickness of λ / 8.

A dielectric spacer 37 having the same material (styrene foam) and a thickness (λ / 8) as the dielectric spacer 35 on the lower surface is laid on the upper surface of the antenna substrate 36. An antenna lens 38 is laid on the upper surface of the dielectric spacer 37. Above the antenna lens 38, a dielectric spacer 4 made of a styrene foam plate having a thickness of about 10 mm
0 is laid.

[0008] When the satellite broadcast radio wave reaching the waveguide 29 is converged on the pickup pin 32 and taken into the LNB 22, it is amplified by the LNB 22 with low noise and frequency-converted from the 12 GHz band to the 1 GHz band. ,
The signal is output to an indoor tuner via a coaxial cable (not shown) connected to the output connector 23 of the LNB 22.

[0009]

However, in the above-mentioned conventional satellite broadcasting antenna, the LNB 22 and the back panel 13 serving also as a reflector are formed in an integrated structure.
Since the entire load of the LNB 22 is applied to the back panel 13, the flatness of the back panel 13, which also functions as a reflector, is reduced, which hinders further improvement in antenna performance.

Further, in the above-described conventional satellite broadcasting antenna, since the circulator and the resonator are integrally formed, energy loss occurs in the resonator. There is a problem that it will.

The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a satellite broadcasting antenna capable of further improving antenna performance.

[0012]

According to a first aspect of the present invention, there is provided a satellite broadcasting antenna in which a plurality of spacers, a feeder line, a radio wave resonator, and a circulator are housed in a predetermined order in a back case, and the back cover is provided by a top cover. The case is closed so as to hermetically close the case, and the LNB is attached to the front side of the back case via a waveguide. The back case may be formed of an aluminum material, the inner surface of the back case may be a reflection plate, and the top cover may be formed of an ASA resin material. Further, the plurality of spacers include first to third spacers, and the first spacer, the feeder line, the second spacer, the radio wave resonator, the circulator, and the third spacer are sequentially housed in the back case. At the same time, the first to third spacers can be made of a material having a high porosity. In addition, the feeding collective line includes a base made of PET material,
On the surface of the base, a plurality of elements are formed by patterning the structure of the feeder line of the antenna with aluminum foil.
/ 4λ. Further, the radio wave resonator has a resonance window corresponding to a plurality of elements of the feeder collective line, and the circulator has a base made of PET material and having a thickness of 1 / 4λ of the wavelength of the radio wave to be received; The base has a plurality of aluminum foil wires at a predetermined angle on a surface opposite to the radio wave resonator side at a predetermined angle in order to cut either one of right-handed and left-handed radio waves of circular polarization. Can be In the satellite broadcasting antenna according to the present invention, a plurality of spacers, a feeder line, a radio wave resonator, and a circulator are housed in a predetermined order in a back case, and the top case is closed so as to hermetically seal the inside of the back case. The LNB is mounted on the front side of the back case via a waveguide.

[0013]

Embodiments of the present invention will be described below.

FIG. 1 is an exploded perspective view showing a flat antenna according to an embodiment of the satellite broadcasting antenna of the present invention, and FIG. 2 explains an antenna fitting for adjusting the azimuth and elevation of the flat antenna of FIG. FIG. 3 is a diagram for explaining the phase of the received radio wave in the flat antenna of FIG. 1, and FIGS. 4 and 5 are diagrams for explaining the wavelength relationship between the feeder line and the LNB of FIG. 6 and 7
8 is a diagram for explaining the radio wave resonator of FIG. 1, FIG. 8 is a diagram for explaining the feeder line of FIG. 1, and FIG. 9 is a diagram for explaining the circulator of FIG.

The flat antenna shown in FIG. 1 includes a back case 1, a waveguide 2, a spacer (A) 3 as a first spacer, a feeder line 4, a spacer (B) 5 as a second spacer, and a screw 7A. , 7B, a wave cap 6, a radio wave resonator 7, a circulator 8, a spacer (C) 9 as a third spacer, a top cover 10, and an LNB 11.

The back case 1 also serves as a reflection plate, and is formed of an aluminum material. In addition, the back case 1 also has a role of protecting each member to be stored.
In the center of the back case 1, a through hole 1E for attaching the waveguide 2 and riveting holes 1A, 1B,
1C and 1D and fixing pins A and B are formed. The waveguide 2 is attached and fixed by the rivets 2A to 2D attached to the rivet stopper holes 1A, 1B, 1C, 1D. Also, fixing pins A and B
Are bosses that serve as references when assembling the parts.

The back case 1 is made of an aluminum metal material. The back case 1 has a mechanical role of reflecting radio waves passing through the feeder assembly line 4 and an electric function of reflecting radio waves by setting the terminal impedance to zero. Role. Here, when the back case 1 is made of an aluminum metal material, the weight of the back case 1 itself can be reduced, and the reflection efficiency of radio waves can be increased.

The back case 1, which also serves as a reflector,
In order to maintain the mechanical strength while maintaining the weight reduction, it is molded with a thickness of, for example, 1.5 to 1.8 mm. The mechanical strength here is essential to maintain the flatness of the reflector, and the higher the flatness, the higher the radio wave reflection efficiency.

On the upper part of the back case 1, a spacer (A) 3, a feeder line 4, and a spacer (B) 5 are sequentially mounted. The spacers (A) 3 and (B) 5 are formed of a material having a dielectric constant close to 1. Here, for example, a material having a high porosity, such as polyurethane, is used to lower the ε of the material. The thickness is 2
mm is preferable. Further, if it can be processed and molded thin, it is also possible to use a polystyrene foam material.

The spacers (A) 3 and (B) 5 and the feeding collective line 4 form a plane coaxial line for transmitting a signal and have an important role of transmitting a signal to a waveguide. The spacer (A) 3 has four through-holes 3E communicating with the through-holes 1E of the back case 1, insertion holes 3A and 3B through which the fixing pins A and B are inserted, and four rivets 2A to 2D. A hole 3C is formed.

The feeding collective line 4 mounted on the spacer (A) 3 is formed by laminating an aluminum foil on a base made of PET material, and further patterning the aluminum foil into a structure of a feeding line of the antenna. It is produced by etching.

Here, the thickness t of the base made of PET material is t =
The thickness of the aluminum foil was 65 microns, and the thickness of the aluminum foil was 15 microns.
This is because the high-frequency current is transmitted on the surface, so that when the thickness of the aluminum foil is increased, the eddy current loss due to the high-frequency resistance increases.

The spacer (B) 5 mounted on the feeder assembly line 4 has the same configuration as the spacer (A) 3 described above, and a description thereof will be omitted. It is essential that the spacer (B) 5 is disposed to face the power supply collective line 4. This is because, as will be described later, it is necessary to form a planar coaxial line around the conductor of the feeding collective line 4.

The radio wave resonator 7 mounted on the spacer (B) 5 is made of a metal plate. The radio wave resonator 7 is preferably made of a material having high electrical conductivity. This is because it is necessary to increase the Q of the RF (high frequency) circuit. As a material, an aluminum material or a tin-plated steel plate material is preferable. Here, the aluminum plate t = 0.3 mm
You are using

The circulator 8 mounted on the radio wave resonator 7 is formed with a thickness of １ ／ λ of the length of the wavelength to be received. As a material of the base of the circulator 8, a PET material that easily transmits a received radio wave was used. As the PET material, a damper material having no transmission loss and no phase delay was used. The thickness was 4 mm.

The circulator 8 is an element for passing either the right-handed circularly polarized wave or the left-handed circularly polarized wave of the circularly polarized wave. Can be passed through. The circulator 8 is mounted at an angle of 45 degrees clockwise with respect to the feeding collective line 4.

The spacer (C) 9 mounted on the circulator 8 enhances the fitting accuracy between the top cover 10 and the back case 1. The top cover 10 mounted on the spacer (C) 9 is made of an ASA resin material. This is to prevent the high frequency signal from being lost and phase distortion from being strong against sunlight. ASA resin materials are used as automobile parts and have excellent durability. The joining of the back case 1 and the top case 10 will be described later.

By the way, since the flat antenna having such a configuration can be installed outdoors, a structure that is resistant to waterproofing and drip-proofing against an external environment such as rain or snow is required. In addition, 7 to 10 years are required as the durability.

The azimuth and elevation angle of the flat antenna having such a configuration are adjusted by using an antenna fitting as shown in FIG. That is, the antenna fitting includes an elevation angle adjustment bracket 13 attached to the LNB spacer 12 via the rotation angle center fixing screw 13a, and a bracket 1
3 is provided with an azimuth adjustment screw 17, a holder band 14 for holding an antenna fixing pole 16, and an elevation adjustment screw 15.

The LNB spacer 12 is used to adjust the wavelength from the position of the above-described feeder line 4 to the pickup pin (see FIG. 10) of the LNB 11 through the waveguide. The elevation adjustment bracket 13 can be changed only in the vertical direction, and is fixed by an elevation adjustment screw 15 for directly adjusting the elevation of the LNB 11.

The elevation angle adjustment bracket 13 and the LNB 11
Are connected by a rotation angle center fixing screw 13a. The elevation angle adjustment bracket 13 is rotatable in the elevation angle direction with the rotation angle center fixing screw 13a as the center of rotation.

The holder band 14 sandwiches the antenna fixing pole 16 in a gap between the bracket 13 for adjusting the elevation angle and the holder band 14.
It can be tightened and fixed at 7.

With such an antenna fitting, the direction and the receiving angle can be stably adjusted toward the satellite receiving the flat antenna and fixed easily.

Next, the phase of the received radio wave at the flat antenna will be described with reference to FIG.

First, in the case where the radio wave of the satellite arrives from the right direction in FIG. 3, the following description will be given using the surface of the aluminum plate of the back case 1 as a reference plane. That is, the phase relation of the wave of the received radio wave at the upper part in the figure will be described.
Since it is a metal, the electric field is zero. Therefore, when viewed electrically, this is equivalent to the existence of an infinite wall.

When the surface of the aluminum plate of the back case 1 has a wavelength at which energy is present, the radio wave is reflected and returns to the feeder line 4. In this case, the incoming radio wave and the reflected radio wave are added and subtracted on the feeding collective line 4, resulting in a negative gain.

Therefore, in order to obtain a gain, it is necessary to set the distance between the surface of the aluminum plate of the back case 1 and the radio wave resonator 7 to λλ of the length of the wavelength to be received. This is the resonance position of the resonator 7. Point P has the largest electric field energy and is also optimal as a position for cutting the circularly polarized wave turning direction.

The spacer (A) 3 and the spacer (B) 5 must be symmetrically arranged. this is,
If the dimensions are not one-to-one to form a plane coaxial line, the transmission impedance will be low and the attenuation will be severe,
This is because the antenna gain decreases. Therefore, the distance between the surface of the aluminum plate of the back case 1 and the radio wave resonator 7 is such that the wavelength λ is 24 mm in the 12 GHz band, and
/ 4 = 6 mm.

In this case, impedance matching can be achieved even when the distance is set to 4 mm in order to shorten the wavelength. Therefore, the mechanical dimensions were set to the following numerical values. 1) Spacer (A) 3 ... 2 mm 2) Feeder assembly line 4 ... 0.1 mm 3) Spacer (B) 5 ... 2 mm 4) Circulator 8 ... 4 to 6 mm 5) Other components Since the dimensions do not affect the antenna gain, they were set appropriately.

Next, the wavelength relationship between the feeder line 4 and the LNB 11 will be described with reference to FIGS.

First, as shown in FIG. 4, between the LNB 11 and the waveguide 2 and the wave cap 6, the back case 1, the spacer (A) 3, and the feeding collective line 4 are superimposed while maintaining flatness. Have been combined. In this state, from the part to be injected into the waveguide shown in FIG.
From the electric field distribution up to the pickup pin of B11, the electric field at the output portion of the feeding collective line 4 is maximized, which is the best point for waveguide injection.

Also, from the output portion of the feeder line 4, LN
It is preferable that the distance to the pickup pin B11 be 1λ, which is the length of the wavelength to be received, as shown in FIG.
Here, up to a point P in the figure indicates an area where a high-frequency signal is transmitted, and points P to Q indicate an area where the high-frequency signal is transmitted in the waveguide. Further, the point Z is a position of １ ／ λ,
This indicates that the impedance is infinite. Therefore, by adopting the above arrangement, the maximum electric field strength can be obtained with the pickup pin of the LNB 11.

Next, the radio wave resonator 7 will be described with reference to FIGS. First, as shown in FIG. 6 (a), the radio resonator 7 has an insertion hole 7-1 through which the fixing pins A and B of the back case 1 are inserted, and a plurality of resonance windows 7-.
2 and an insertion hole 7-3 shown in FIG. 6C through which the wave cap 6 is inserted. And the insertion hole 7
When the fixing pins A and B of the back case 1 are inserted through −1, the plurality of resonance windows 7-2 are positioned so as to receive the feeding collective line 4.

242 resonance windows 7-2 are formed. Further, as shown in FIG. 6D, the resonance window 7-2
The dimensions are 12.5 mm in length and 13.2 mm in width.
The material of the radio wave resonator 7 is aluminum, and its thickness is shown in FIG.
As shown in (b), it is 0.3 mm.

The dimensions of the resonance window 7-2 shown in FIG. 6D are obtained based on the principle of FIG. That is, as shown in FIG. 7A, a window that resonates at a required frequency is formed in the waveguide, and a signal is injected from the direction of the arrow in the figure. Of capacity. If this is shown by an electric equivalent circuit, a tank circuit which is a resonance circuit of L and C as shown in FIG. 7B is formed.

The formula for calculating the C or L susceptance between the short side and the long side of the window is as follows. Capacitance: (in the short side direction) B = (4b / λg) Ln {cosec (πd / 2b)}
Becomes In the case of inductiveness: (in the case of the long side direction) B = − (λg / a) cot ＾ 2 (πd / 2a).
In addition, when a square window is formed in the center, the susceptance is represented by the following equation. B = (3 / 2π) (abλg / d ＾ 3) Therefore, the susceptance when the window (long side a, short side b) shown in FIG. 7
(C).

As described above, by resonating the size of the opening window to the frequency of the BS broadcast, the energy of the radio wave is multiplied by Q according to the size of Q of the opening window, and the electric field intensity is increased. Therefore, in the case of a flat antenna,
The energy resonated in the large number of resonance windows 7-2 can be coupled to the facing feeding collective line 4, and the resonated signals can be collected and guided to the waveguide.

Next, the feeding collective line 4 will be described with reference to FIG.

As shown in FIG.
Has a plurality of elements 4a. Further, the standing wave on the feeding collective line 4 is as shown in FIG. Also,
As shown in FIG. 8C, each element 4a has a length of λλ in the vertical direction and the horizontal direction.
It has a structure that can receive both V signals. Also, B
In the case of S broadcast, since only the H mode is used, the waveguide uses a square waveguide.

The feeding collective line 4 uses a film in which aluminum having a thickness of 15 μm is printed on PET having a thickness of t = 65 μm. As described above, by using PET, the flatness of the feeding collective line 4 can be easily obtained, so that the production yield can be increased.

Next, the circulator 8 will be described with reference to FIG.

As shown in FIG. 9A, the circulator 8 has a pattern formed of aluminum foil on a damper. The thickness of the aluminum foil is 0.05 mm, and the thickness of the damper is 4 mm as shown in FIG. 9B.

The pattern of the aluminum foil is shown in FIG.
As shown in the figure, the length is 1λ, and the interval between each pattern is １ ／.
λ, which is inclined 45 degrees clockwise. With such a configuration, as shown in FIG. 9C, only the right-handed polarized wave can be extracted and the left-handed polarized wave can be cut, so that the BS signal can be extracted. Of course, as shown in FIG. 9D, if the pattern of the aluminum foil is tilted 45 degrees counterclockwise, only the right-handed polarized wave can be extracted.

As described above, by forming the circulator 8 with a pattern formed of aluminum foil on the damper, a structure can be ensured between the radio wave resonator 7 located below the circulator 8 and the circulator 8. , Energy loss can be greatly reduced. As described above, since the energy loss can be significantly reduced, the gain of the flat antenna can be improved.

As described above, in the present embodiment, the spacer (A) 3, the feeder line 4, the spacer (B) 5, the wave cap 6, the radio wave resonator 7,
The circulator 8 and the spacer (C) 9 are sequentially stored,
Since the inside of the back case 1 is closed by the top cover 10 so as to hermetically close, and the LNB 11 is mounted on the front side of the back case 1 via the waveguide 2, the flatness of the back case 1 also serving as a reflection plate is provided. And the loss of resonance energy can be suppressed by insulating the circulator 8 and the radio wave resonator 7, so that the antenna performance can be further improved.

[0056]

As described above, according to the satellite broadcasting antenna of the present invention, a plurality of spacers, a feeder line, a radio wave resonator, and a circulator are housed in a predetermined order in a back case, and the back cover is enclosed by a top cover. And the LNB is attached to the front side of the back case via a wave guide,
The antenna performance can be further improved.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a flat antenna according to an embodiment of the satellite broadcasting antenna of the present invention.

FIG. 2 is a view for explaining an antenna fitting for adjusting the azimuth and elevation angle of the flat antenna of FIG. 1;

FIG. 3 is a diagram for explaining a phase of a received radio wave in the flat antenna of FIG. 1;

FIG. 4 is a diagram illustrating a wavelength relationship between a feeder line and an LNB in FIG. 1;

FIG. 5 is a diagram illustrating a wavelength relationship between the feeder line and the LNB in FIG. 1;

FIG. 6 is a diagram for explaining the radio wave resonator of FIG. 1;

FIG. 7 is a view for explaining the radio wave resonator of FIG. 1;

FIG. 8 is a diagram for explaining a feeder line of FIG. 1;

FIG. 9 is a diagram for explaining the circulator of FIG. 1;

FIG. 10 is a diagram illustrating an example of a conventional flat antenna.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Back case 2 Wave guide 3 Spacer (A) 4 Feeding collective line 4a Element 5 Spacer (B) 6 Wave cap 7 Radio wave resonator 7-2 Resonance window 8 Circulator 9 Spacer (C) 10 Top cover 11 LNB 12 LNB spacer 13 Bracket 14 Holder band 15 Elevation angle adjustment screw 16 Antenna fixing pole

Claims (5)

[Claims] 1. A plurality of spacers in a back case,
A power supply collective line, a radio resonator, and a circulator are housed in a predetermined order, and the top case is closed so as to hermetically seal the inside of the back case, and an LNB is attached to the front side of the back case via a waveguide. A satellite broadcasting antenna. 2. The back case is molded from an aluminum material, the inner surface of the back case is a reflection plate, and the top cover is molded from an ASA resin material. 2. A satellite broadcasting antenna according to claim 1. 3. The plurality of spacers include first to third spacers, and the first case is provided in the back case.
The spacer, the feeder line, the second spacer, the radio wave resonator, the circulator, and the third spacer are sequentially housed, and the first to third spacers are made of a material having a high porosity. 2. The satellite broadcasting antenna according to claim 1, wherein the antenna is molded. 4. The power supply assembly line comprises a base made of PET material, a plurality of elements having a structure of a feeder line of the antenna formed by patterning an aluminum foil on a surface of the base, and the plurality of elements. The satellite broadcasting antenna according to claim 1, wherein は is set to １ ／ λ of a wavelength length of a radio wave to be received. 5. The radio wave resonator has a resonance window corresponding to a plurality of elements of the feeder line, and the circulator is made of PET material and has a thickness of 1 / 4λ of a wavelength of a radio wave to be received. And a plurality of aluminum foils at a predetermined angle on a surface of the base opposite to the radio wave resonator side to cut any one of right-handed and left-handed circularly polarized radio waves. 2. The method according to claim 1, wherein the line has a line.
Or the satellite broadcast antenna according to 3.