JP3890678B2 - Low noise block converter - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a low noise block converter (LNB) in which a housing is formed integrally with a primary radiator.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a low noise block converter (hereinafter referred to as LNB) having a housing integrated with a primary radiator is disposed, for example, on a satellite dish receiving parabola antenna and has a horn at the tip of a waveguide. The microwave received by the antenna is transmitted to the LNB through the waveguide, where it is converted to an intermediate frequency. This intermediate frequency is then supplied from the LNB to the satellite receiver.
[0003]
FIG. 3 is a cross-sectional view showing an embodiment of an LNB in which a housing is integrated with a conventional primary radiator, an example in which a die-cast shield is provided (A), and an example in which a waveguide die-cast short is provided ( B) Reference numeral 1 denotes a metal housing, for example, a die-cast chassis using a material such as aluminum or zinc. A primary radiator 2 includes a waveguide and a horn provided at the tip. 3 is a die-cast shield for electromagnetically shielding a circuit such as an ultra-low noise amplifier circuit and short-circuiting the waveguide. 3a is a die-cast short for short-circuiting the waveguide. Reference numeral 4 denotes an electromagnetic shield and a metal shield plate (lid) for preventing moisture, dust and the like from entering the housing. 5 is a circuit board constituted by a microstrip line in which a signal line pattern or a ground pattern is provided on a dielectric plate such as Teflon, and a HEMT (High Electron Mobility Transistor) or a gallium arsenide transistor is mounted on the pattern. is there. Reference numeral 6 denotes a circuit component mounted on the circuit board 5.
[0004]
In FIG. 3A, the die-cast shield 3 is necessary for electromagnetically shielding a high-frequency circuit such as an ultra-low noise amplifier circuit and for short-circuiting the waveguide. The die-cast shield 3 is installed behind the die-cast shield 3 by a distance of 1/4 wavelength of the microwave received from the position of the probe that couples the provided microstrip line and the waveguide.
[0005]
Further, in FIG. 3A, an example in which a high-frequency circuit such as an ultra-low noise amplifier circuit is housed in a space obtained by digging the die-cast chassis 1 to obtain an electromagnetic shielding effect is used here. The die-cast short 3a is necessary for short-circuiting the waveguide, and the bottom surface of the die-cast short 3a is rearward from the position of the probe provided on the circuit board 5 by a distance of 1/4 wavelength of the microwave. It is installed to become.
[0006]
As described above, the conventional example of FIGS. 3A and 3A requires the die-cast shield 3 or the die-cast short 3a in addition to the die-cast chassis 1. Accordingly, in any of the conventional examples, when the die-cast chassis 1 and the shield plate 4 are combined, the number of main structural parts is three and the number of parts is large.
[0007]
In particular, the die-cast shield 3 or the die-cast short 3a is required to have a complicated shape, shielding effect, dimensional accuracy, and the like, so that precision parts by die-casting are required, resulting in an increase in cost.
[0008]
[Problems to be solved by the invention]
The present invention has been made in view of the above problems, and an object thereof is to provide a low noise block converter (LNB) in which the number of die-cast parts is reduced.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, a low noise block comprising a housing having a space for accommodating a high frequency circuit provided on a circuit board and integrally forming a waveguide portion for transmitting a microwave input from a primary radiator. In the converter (LNB), the housing is formed by opening a space provided in a plurality of sections for accommodating the high-frequency circuit and electromagnetically shielding it in a direction opposite to the direction in which the microwave is input, A probe is provided on the circuit board so as to protrude from the circuit board, and an opening for inserting the probe is provided at a predetermined position from the rear end of the waveguide part on the side surface of the waveguide part. Configured.
[0010]
In addition, the opening is configured by a slit extending from the rear end of the waveguide portion to a required position.
[0011]
In addition, a hole for inserting the probe was formed by fitting a conductive member into the slit.
[0012]
A member that short-circuits the rear portion of the waveguide portion from the opening at a required position is used as a lid of the housing.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Since it comprised as mentioned above, the probe protruded from the circuit board is hold | maintained in the state penetrated in a waveguide, for example in the opening hung down on the side surface of the waveguide part . The probe is held at a position of a quarter wavelength of the microwave received from the rear end of the waveguide portion, and the rear end of the waveguide portion is short-circuited. Therefore, the microwaves in the waveguide are coupled by the probe and transmitted to a low noise block converter (LNB) where it is converted to an intermediate frequency.
[0014]
Furthermore, a short circuit (short circuit) at the rear end of the waveguide portion can be shared with the housing lid for electromagnetic shielding.
[0015]
【Example】
Hereinafter, a low noise block converter (LNB) according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram showing an embodiment of a low noise block converter (LNB) according to the present invention. In addition, the same number is attached | subjected to the same location as a prior art example. Reference numeral 1 denotes a metal housing, for example, a die-cast chassis using a material such as aluminum or zinc. 2a is a waveguide of the primary radiator 2 comprises along the sides of the cylindrical shape, the slit-like opening 8 of approximately 1/4 the length of the wavelength of the received microwave. 5, for example, a signal line pattern or a ground pattern is provided on a dielectric plate such as Teflon, and a HEMT (High Electron Mobility Transistor) or a gallium arsenide transistor is mounted on the pattern. This is a circuit board provided with a probe 7 for coupling at the end of the strip line. The opening 8 is fitted a conductive member in a slit which is formed by die-casting, it may be holes for inserting the probe 7.
[0016]
The structure and operation of a low noise block converter (LNB) according to the present invention will be described with reference to FIGS. FIG. 2 is a cross-sectional view of the main part showing an embodiment of a low noise block converter (LNB) according to the present invention. The primary radiator 2 is suspended from the end of the die cast chassis 1, and the circuit board 5 is accommodated in the die cast chassis 1 in a direction perpendicular to the primary radiator 2. Then, an opening 8 is provided to a quarter position of the wavelength of the microwave received from the rear end of the waveguide portion 2a of the primary radiator 2, the probe 7 which is provided at an end portion of the circuit board 5 opening 8 is inserted into the waveguide section 2a. In addition, the rear opening of the waveguide section 2a is short-circuited at a position of 1/4 wavelength from the opening, and moisture, dust, etc. enter the electromagnetic shield of the die-cast chassis 1 (housing) and the housing. In order to prevent this, a shield plate (lid) 4 was attached to the back of the die-cast chassis 1 (housing). The present invention is to obtain an electromagnetic shielding effect by accommodating the high frequency circuit such as an ultra low noise amplifier circuit in a space provided by sectioning the Write-plurality digging diecast chassis 1.
[0017]
Further, as a method of configuring the probe 7, the circuit board 5 of the corresponding microstrip line part may be cut out and protruded, or a pin or the like may be attached to the corresponding microstrip line part of the circuit board 5. Also good.
[0018]
【The invention's effect】
As described above, the present invention provides a low noise block converter (LNB) with a reduced number of die cast parts. As shown in FIG. 3, the conventional embodiment requires the die-cast shield 3 or the die-cast short 3a, but these can be reduced in the present invention. Therefore, there is an advantage that the cost can be reduced by reducing the number of expensive die-cast parts. In addition, since the shield plate (lid) 4 is installed at a position of 1/4 wavelength from the position of the circuit board 5 (opening), the thickness of the LNB can be reduced.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing an embodiment of a low noise block converter (LNB) according to the present invention.
FIG. 2 is a cross-sectional view of an essential part showing an embodiment of a low noise block converter (LNB) according to the present invention.
FIG. 3 is a cross-sectional view showing an embodiment of an LNB in which a housing is integrated with a conventional primary radiator, an example in which a die-cast shield is provided (A), and an example in which a waveguide die-cast short is provided. (B).
[Explanation of symbols]
1 Die-cast chassis (housing)
2 Primary radiator
2a Waveguide section
3a Die-cast short 3 Die-cast shield 4 Shield plate (lid)
5 circuit board 6 circuit components 7 probe 8 opening

Claims (4)

In a low noise block converter (LNB) comprising a housing having a space for accommodating a high frequency circuit provided on a circuit board and integrally forming a waveguide portion for transmitting a microwave input from a primary radiator,
The housing is formed by opening a space provided in a plurality of sections for housing the high-frequency circuit and electromagnetically shielding it in a direction opposite to the direction in which the microwave is input. A low noise characterized in that a probe is provided so as to protrude from the substrate, and an opening for inserting the probe is provided at a required position from the rear end of the waveguide part on the side surface of the waveguide part. Block converter. 2. The low noise block converter according to claim 1, wherein the opening is a slit extending from a rear end of the waveguide portion to a required position.   The low noise block converter according to claim 2, wherein a hole for inserting the probe is formed by fitting a conductive member into the slit. 4. The low noise block converter according to claim 1, wherein a member for short-circuiting a rear portion of the waveguide portion is a cover of the housing.

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