KR20030004794A - Feeding system for receiving both cp signal and lp signal using cut-off frequency - Google Patents

Abstract

PURPOSE: A system for simultaneously feeding a circular polarization and a linear polarization using a cut-off frequency by employing a waveguide structure that separates two signals according to the difference of frequency bandwidths and feeds them. CONSTITUTION: A first waveguide(30) passes a circular polarization and a linear polarization. A second waveguide(40) is connected to the first waveguide(30), has a width less than that of the first waveguide(30), and passes the circular polarization by a cut-off frequency corresponding to the width thereof. A first probe(35) is mounted toward an inside of the first waveguide(30) to receive the linear polarization. A second probe(40) is mounted on a lower end of the second waveguide(40) to receive the circular polarization. An LNB(Low Noise Blockdown) substrate(50) converts frequencies of the signals received from the first probe(35) and the second probe(40) to generate an intermediate signal.

Description

Circular polarization and linear polarization simultaneous feeding system using cutoff frequency {FEEDING SYSTEM FOR RECEIVING BOTH CP SIGNAL AND LP SIGNAL USING CUT-OFF FREQUENCY}

The present invention relates to a feeding system of a satellite broadcasting receiver for receiving linear polization (LP) and circular polization (CP) at the same time, in particular, the linear and circular polarization transmitted from the broadcast satellite The present invention relates to a satellite broadcasting receiver feeding system capable of simultaneously receiving each type of polarized wave by employing a waveguide structure capable of feeding two signals separately according to frequency band differences.

In general, 12 GHz satellite broadcasting signals emitted from a broadcasting satellite are received by a satellite broadcasting antenna, and the satellite broadcasting receiving antenna focuses the received satellite broadcasting signals and blocks low noise through a feeding system of the satellite broadcasting apparatus. blockdown: LNB) Converts to an intermediate frequency in the converter. At this time, the received satellite broadcasting signal is classified into linear polarization and circular polarization according to the characteristics of the polarization. The linear polarization includes vertical polarization and horizontal polarization, and in the circular polarization, left circular polarization (LHCP) and preferred circular polarization. (RHCP).

The feeding system of the satellite broadcasting apparatus is generally composed of a feed horn and a waveguide connected to the bottom thereof and a probe for receiving a signal, but the structure of the waveguide and the shape of the probe vary depending on the frequency band and polarization characteristics of the satellite broadcasting signal.

Conventionally, a feeding system of a satellite broadcasting receiver has taken a structure for receiving only one type of signal of linear polarization and circular polarization. Hereinafter, the satellite broadcasting receiver will be described with reference to the drawings.

1 is a schematic diagram of a feeding system implemented in a conventional satellite broadcasting receiver. Referring to Figure 1 (a), a conventional satellite broadcasting receiver for linear polarization is shown. The satellite broadcasting receiver includes a feed horn (1), a waveguide (2), and an LNB converter (3), and includes a vertical polarization reception probe (5) and a horizontal polarization reception probe (mounted to the waveguide (2)). 6), a structure in which the signal received through 6) is independently transmitted to the LNB converter unit 3.

On the other hand, in the case of a feeding system for receiving a circular polarization, as shown in FIG. 1 (b), the circular polarization is converted into linearly polarized wave in the waveguide 2 connecting the feed horn 1 and the LNB converter 3. A polarizer 8 and a probe 9 for receiving vertical and horizontal polarizations of linearly polarized waves converted by the polarizer 8 are mounted.

In general, the feeding system of FIG. 1 (b) inserts a dielectric plate into the circular waveguide through the polarizer 8 to generate a phase shift to convert circular polarization into linear polarization, and converts the converted linear polarization into the probe ( It is configured to receive circular polarized signal by receiving through 9).

In addition to the above-described form, satellite broadcasting receivers having various functions and forms have been developed in the prior art, but there has been no description of a receiver for simultaneously receiving linear and circular polarized waves. However, in recent years, the use of linear polarization and circular polarization in broadcast satellite communication at the same time, there is a need for a new satellite broadcast receiver capable of receiving these signals simultaneously.

However, in the case of combining the conventional receivers according to each polarization type into one device, there is a problem that the loss due to the interference between the two types of signals is large and cannot be commercialized, and each feeding system is separately installed. There is a problem that excessive production cost occurs.

Accordingly, there is a need in the art for a system for receiving a new satellite broadcasting receiver capable of simultaneously receiving signals of linear and circular polarizations in a single feeding system and further minimizing mutual interference between linear and circular polarizations.

An object of the present invention is to form a waveguide having a different width according to the inherent cutoff frequency of the linear polarization and the circular polarization in the satellite broadcasting receiver, and receives the signal to minimize the mutual interference of the linear and circular polarization To provide a feeding system.

Furthermore, an object of the present invention is to provide a feeding system in which the bent surface acts as a reflector by forming a portion bent by the difference in the waveguide width and having a surface substantially perpendicular to the receiving direction of the signal without forming a separate reflector. It is.

1 is a schematic diagram of a feeding system employed in a conventional satellite broadcasting receiver.

2 (a) is a schematic diagram of a satellite broadcasting receiver feeding system according to the present invention.

Figure 2 (b) is a schematic diagram of a printed circuit board patterned with a second probe employed in the present invention.

3 is a schematic diagram of a feeding system according to an embodiment of the present invention.

<Code Description of Main Parts of Drawing>

20: feedhorn 30: first waveguide

35: first probe 40: second waveguide

45: second probe 50: LNB substrate

The present invention relates to a feeding system of a satellite broadcasting receiver, comprising: a first waveguide through which linear and circular polarizations pass; and an inner width connected to the first waveguide and having an inner width smaller than that of the first waveguide, and corresponding to the inner width. A second waveguide for passing only the circularly polarized wave at a cutoff frequency, a first probe mounted toward the inside of the first waveguide to receive linearly polarized wave, and mounted at a lower end of the second waveguide to receive circularly polarized wave. A feeding system comprising a second probe and an LNB substrate for generating an intermediate signal by converting a frequency of a signal received from the first probe and the second probe.

The feeding system having such a structure can simultaneously receive each other by minimizing mutual interference when the satellite broadcast signal is composed of a linear polarization having a predetermined frequency band and a circular polarization having a frequency band higher than the frequency of the linear polarization.

Further, in a preferred embodiment of the present invention, the connection portion between the first waveguide and the second waveguide is bent to have a surface substantially perpendicular to the receiving direction of the satellite broadcasting signal, without forming a separate reflector by using the surface. It can serve as a reflective surface for the first probe.

Furthermore, in another embodiment of the present invention, mutual interference can be effectively prevented by changing modes of the first waveguide and the second waveguide. For example, the first waveguide may be a circular waveguide, the second waveguide may be a square waveguide, and vice versa.

Further, in a preferred embodiment of the present invention, the second probe includes a first end for receiving a vertical vector component of circular polarization and a second end for receiving a horizontal vector component, the ends being 90 ° out of phase with each other. In particular, the LNB substrate may be mounted on the bottom of the second waveguide, and the second probe may be embodied by patterning the second probe on the LNB substrate region bonded to the inside of the second waveguide.

EMBODIMENT OF THE INVENTION Hereinafter, one Embodiment of this invention is described in detail with reference to drawings.

Figure 2 is a schematic diagram of a satellite broadcasting receiver according to an embodiment of the present invention. Referring to Figure 2 (a), the feed horn 20, the first waveguide 30 connected to the lower end of the feed horn 20 and The feeding system of the satellite broadcasting receiver comprising the second waveguide 40 and the LNB substrate 50 connected to the bottom of the second waveguide 40 is shown.

A characteristic of the present invention is to configure one waveguide by connecting the first waveguide 30 and the second waveguide 40 having a width smaller than that of the first waveguide 30. The waveguide used in the feeding system has the characteristic of a high pass filter having a specific cutoff frequency according to its width. That is, the waveguide does not pass a signal having a frequency lower than its cutoff frequency. In the present invention, using the cutoff frequency characteristic, the satellite broadcasting receiver of the present invention minimizes the interference according to a unique frequency band by receiving only a specific frequency signal of the first waveguide from the second waveguide having a small width. Can be.

Hereinafter, the relationship between the waveguide width and the cutoff frequency will be described in the following equation for a complete understanding of the cutoff frequency characteristics of the waveguide employed in the present invention.

Formula (1)

Formula (2)

The first equation is a relation between the cutoff frequency f _co and the length (a) of one side of the square waveguide in the basic mode (T11 mode), and the second equation is the cutoff frequency f in the circular waveguide of the basic mode (T10 mode). _co ) and its diameter (R). Where μ is the permeability of the waveguide material and ε represents the permittivity of the waveguide material.

As described above, the inherent cutoff frequency can be selected by adjusting the width (length or diameter of the waveguide) of the waveguide, and the interference of other signals in the frequency band can be solved by constructing waveguides having different widths.

On the basis of this principle, in the present invention, in receiving a satellite broadcast signal having a linear polarization having a predetermined frequency band and a circular polarization higher than the frequency band, the first waveguide 30 and the linear polarization have a corresponding frequency band. By connecting and integrating the second waveguide 40 having a blocking width, only the circularly polarized signal of the satellite broadcast signal passing through the first waveguide 30 is passed through the second waveguide 40 to mutual interference between the circularly polarized wave and the linearly polarized wave. Can be minimized.

That is, in the present invention, linear polarization of the satellite broadcast signal is received by the first probe 35 mounted toward the inside of the first waveguide 30, and only circular polarization that is not received by the first waveguide 30 is then received. It passes through this second waveguide 40 and is received by a second probe 45 mounted at its lower end.

FIG. 2 (b) shows the LNB substrate 50 implementing the second probe 45 in a conductor pattern. The second probe 45 has two ends 45a and 45b, and receives the vertical and horizontal vector components of the circularly polarized wave through the respective ends 45a and 45b. It is configured to transmit to the LNB circuitry (not shown) through a pattern connecting the two other ends to one.

Another feature of the present invention is to form a bent surface A formed at the connection portion between the first waveguide 30 and the second waveguide 40 substantially perpendicular to the signal receiving direction (shown by the arrow in Fig. 2 (a)). Through the vertical bent surface (A) it can serve as a reflective surface for the first probe (35). Therefore, the present invention has the advantage that it is not necessary to mount a separate reflector at the rear end of the first probe 35.

According to another embodiment of the present invention, the first waveguide can be formed as the circular waveguide 60 and the second waveguide can be formed as the square waveguide 70. By varying the shape of the waveguide, the loss can be minimized by more effectively preventing the interference between the linear polarization received from the first probe 65 of the circular waveguide 60 and the circular polarization received from the bottom of the square waveguide 70. Of course, unlike the present embodiment, the same effect can be expected even when the first waveguide is a square waveguide and the second waveguide is a circular waveguide. On the other hand, the second waveguide may take the form of a straight line, as shown in FIG.

As described above, according to the feeding system of the present invention, by using the first waveguide and the second waveguide having different widths, the linear and circular polarized waves having different unique cutoff frequencies are simultaneously received without mutual interference, and further, It is possible to provide a satellite broadcasting receiver in which the bent surface acts as a reflector by forming a portion bent by the difference in the waveguide width to be substantially perpendicular to the receiving direction of the signal without forming a reflector. In addition, by changing the modes of the first waveguide and the second waveguide, it is possible to provide a feeding system capable of effectively preventing mutual interference due to linear polarization and circular polarization.

The detailed description of the invention is provided for purposes of illustration and description. It is not intended that the invention be strictly limited as disclosed, the scope of the invention being defined by the appended claims rather than this detailed description. It is to be understood that the foregoing specification, embodiments are intended to provide a description of the components of the invention and that each component is capable of numerous modifications or variations in light of the above teaching.

Claims (6)

In a feeding system of a satellite broadcasting receiver for receiving a signal consisting of a linear polarization having a predetermined frequency band and a circular polarization having a frequency band higher than the frequency band of the linear polarization, A first waveguide for passing the linearly polarized wave and the circularly polarized wave; A second waveguide connected to the first waveguide, the second waveguide having a width smaller than that of the first waveguide and allowing only the circularly polarized wave to pass through at a cutoff frequency corresponding to the width; A first probe mounted toward the inside of the first waveguide to receive a linearly polarized wave; A second probe mounted to a lower end of the second waveguide to receive circular polarization; And a LNB substrate for generating an intermediate signal by converting a frequency of a signal received from the first probe and the second probe. The method of claim 1, And a connecting portion of the first waveguide and the second waveguide is bent to have a surface substantially perpendicular to the receiving direction of the satellite broadcasting signal. The method of claim 1, And said first waveguide is a circular waveguide and said second waveguide is a square waveguide. The method of claim 1, And said first waveguide is a square waveguide and said second waveguide is a circular waveguide. The method of claim 1, The second probe includes a first end for receiving a vertical vector component of circular polarization and a second end for receiving a horizontal vector component, wherein the first and second ends have a phase difference of 90 ° from each other. Feeding system. The method of claim 1, The LNB substrate is mounted to the bottom of the second waveguide, And the second probe is patterned and formed on the LNB substrate region bonded to the inside of the second waveguide.