JP2960835B2 - Low noise converter circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low noise converter circuit for amplifying and frequency converting a signal from a broadcasting satellite received by a receiving antenna and outputting the signal to a tuner circuit.

[0002]

2. Description of the Related Art A low-noise block down converter (hereinafter referred to as LNB) amplifies low-noise signals of a horizontal polarization signal and a vertical polarization signal having a frequency of several tens of GHz, which are received by a receiving antenna. The signal is converted into an intermediate frequency signal and output to a tuner circuit at the subsequent stage.

The conventional LNB circuit shown in FIG. 4 is a two-output type circuit that receives and outputs horizontal and vertical polarization signals at the same time. Is amplified and frequency-converted, and a local oscillation signal is divided into two and supplied from one local oscillator to a mixing circuit of each system.

That is, this circuit amplifies a horizontally polarized signal HP input to an input terminal 21 by a low noise amplifier (hereinafter referred to as LNA) 22 composed of a three-stage HEMT (high electron mobility transistor) element. In a mixing circuit 23, the signal is mixed with a local oscillation signal Lo from a local oscillator 24, converted into an intermediate frequency signal IH, and passed through a switch circuit 25 to a two-stage intermediate frequency amplifier circuit (hereinafter referred to as IFA) 26 (or 27). ) To amplify the signal to an appropriate level and output to terminal 2
8 (or 29).

Further, the vertically polarized signal VP input to the input terminal 30 is amplified with low noise by an LNA 31 having the same configuration as the LNA 22, and mixed with a local oscillation signal Lo from a local oscillator 24 by a mixing circuit 32 to produce an intermediate frequency signal. IV, and through a switch circuit 25, a two-stage IFA 27 (or 2
In 6), the signal is amplified to an appropriate level and output from the output terminal 29 (or 28).

FIG. 5 is a diagram showing a configuration in which a local oscillation signal Lo is supplied from a local oscillator 24 to two mixing circuits 23 and 32 through a Y-type power divider 33. FIG.
Is disclosed in Japanese Patent Application Laid-Open No. H11-27138. By disposing mixing circuits 23 and 32 each using a gallium arsenide Schottky diode as a mixer element so as to be symmetrical with respect to a local oscillator 24, high isolation (a difference between a horizontally polarized signal and a vertically polarized signal) can be achieved. (Degree of separation).

[0007]

However, when a diode mixer is used as a mixing circuit, the mixing circuit has no amplifying action, so that the LNA amplifying element must have a multistage configuration, making it difficult to reduce the size of the circuit board. Becomes

[0008] Therefore, M including an amplifying element and a mixer element
2. Description of the Related Art A converter circuit has been proposed which realizes cost reduction and miniaturization using an MIC (microwave monolithic integrated circuit). However, as a mixer element, F
When using an ET (field effect transistor), HEMT element or MMIC including these active elements,
When a local oscillator and two MMICs are connected by a Y-type power divider, the influence between the MMICs is greater than that of a diode mixer, and there is a disadvantage that isolation is deteriorated.

Further, since the MMIC has a single pin arrangement due to the structure of the MMIC, as shown in FIG.
When connecting the two MMICs 41 and 42, the MMI
Since the local input pins of C41 and C42 are both located on the lower side of the package in this figure, the wiring of the MMIC 42 must be bypassed as shown by a broken line, and two MMICs 41 are connected to the local oscillator 24. , 42 cannot be arranged symmetrically. Therefore, the local oscillation signal Lo is set to M
There is a disadvantage that the MICs 41 and 42 cannot be equally distributed.

Therefore, the present invention reduces the power of the local oscillation signal by two.
An object of the present invention is to evenly divide and supply two mixed circuits to one mixed circuit and to reduce the size of the circuit board.

[0011]

SUMMARY OF THE INVENTION The present invention provides a two-output low noise converter circuit for converting a horizontal and vertical polarization signal received by a receiving antenna into an intermediate frequency signal and outputting the intermediate frequency signal. First and second microwave semiconductor integrated circuits including a mixer element for converting a signal into an intermediate frequency signal, a local oscillator for supplying a local oscillation signal to the first and second microwave semiconductor integrated circuits, a local oscillator and a second oscillator. A Y-type power divider for connecting the first and second microwave semiconductor integrated circuits, wherein the first and second semiconductor integrated circuits are symmetric with respect to the local oscillator via the Y-type power divider. It is configured to have different pin arrangements so as to be arranged at positions.

In this case, each of the first and second semiconductor integrated circuits has a local oscillation signal input pin on the Y-type power splitter side, and is connected to the Y-type power splitter via a capacitor.

[0013]

In the structure of the present invention, the first and second microwave semiconductor integrated circuits are arranged in mutually different pins so as to be arranged symmetrically with respect to the local oscillator. Has a local oscillation signal input pin. For this reason, the local oscillation signal from the local oscillator is equally divided into two and supplied via the Y-type power divider.

[0014]

FIG. 1 is a block diagram showing an embodiment of a converter circuit according to the present invention. This embodiment includes an input terminal 1 to which a horizontal polarization signal HP is input and an input terminal 2 to which a vertical polarization signal VP is input. The input terminal 1 is connected to an LNA 3 composed of a two-stage HEMT element. , Input terminal 2
Are also connected to an LNA 4 composed of two-stage HEMT elements.

The output of LNA 3 is connected to MMIC 5 containing an active mixer, and the output of LNA 4 is connected to MMIC 6 also containing an active mixer. MMI
Since the switch circuit 25 shown in FIG. 4 is also included in C5, the output of the MMIC 6 is connected to the MMIC 5. As will be described later, the MMICs 5 and 6 are connected so that the local oscillation signal Lo from the local oscillator 7 is evenly distributed.

The output of the MMIC 5 is a one-stage IFA 8
And 9, the outputs of the amplifier circuits 8, 9 are
They are connected to output terminals 10 and 11, respectively.

FIG. 2 is a layout diagram showing a connection relationship between the two MMICs 5 and 6 and the local oscillator 7. In this case, MM
As shown in FIG. 3 (a), the IC 5 has a signal input pin 5a on the left side of the package and a signal output pin 5 on the right side.
b is the DC power supply pin 5 on the upper side to which the DC power supply DC is supplied.
c has a configuration in which local oscillation input pins 5d to which the local oscillation signal Lo is input are arranged on the lower side.

On the other hand, as shown in FIG. 3B, the MMIC 6 has a signal input pin 6a on the left side of the package, a signal output pin 6b on the right side, a local oscillation input pin 6c on the upper side, and a lower side of the package. The DC power supply pins 6d are arranged on the sides, and the MMIC 5 has a structure in which the DC power supply pins and the local oscillation input pins are interchanged.

For this reason, as shown in FIG. 2, the position of the MMICs 5 and 6 with respect to the local oscillator 7 becomes a mirror image, and a configuration can be realized in which the local oscillator power is equally distributed into two through the Y-type power divider 12. Further, in this embodiment, a high isolation design becomes possible by inserting the capacitors C1 and C2 on the local transmission line. Further, not only the pin arrangement but also the MMIC existing in the two-system circuit is coupled by the power distributor. In this case, the effects of the MMICs are reduced so that high isolation can be realized.

In this configuration, the horizontally polarized signal HP input to the input terminal 1 is amplified by the LNA 3 with low noise,
The MMIC 5 mixes the frequency with the local oscillation signal Lo and frequency-converts it into an intermediate frequency signal IH. For example, a horizontally polarized signal H having a frequency of 10.95 to 11.7 GHz amplified by the LNA 3
P is mixed with a local oscillation signal Lo having a frequency of 10 GHz by a mixing circuit in the MMIC 5 to produce a frequency of 950 to 1700 M
Hz intermediate frequency signal IH. Similarly, the vertical polarization signal VP input to the input terminal 2 is the intermediate frequency signal IV.
Is converted to

The intermediate frequency signals IH and IV are
5, and the intermediate frequency signal IH is output from the output terminal 10 (or 11) after being amplified by the IFA 8 (or 9).
Is output terminal 11 after being amplified by IFA 9 (or 8).
(Or 10).

[0022]

According to the present invention, by using two types of MMICs having different pin arrangements, two MMICs can be arranged symmetrically with respect to the Y-type power divider, so that the power of the local oscillation signal can be reduced. Can be supplied evenly divided.

Further, by using the MMIC including the active mixer, the size of the substrate can be reduced, and in addition, the front and rear amplifier circuits, that is, the LNA and the IF
Since the number of stages A can be reduced, the number of parts can be reduced and the transmission line can be simplified, so that the size can be further reduced, and the cost and size of the LNB can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of a low noise converter circuit according to the present invention.

FIG. 2 is a layout diagram showing a connection state between a local oscillator and an MMIC.

FIG. 3 is a configuration diagram of an MMIC having two different types of pin arrangements.

FIG. 4 is a block diagram showing an example of a conventional low noise converter circuit.

FIG. 5 is a diagram showing a coupling relationship between a local oscillator and a mixing circuit by a Y-type power divider.

FIG. 6 is a configuration diagram using a Schottky diode as a mixing circuit.

FIG. 7 is a diagram illustrating that an MMIC cannot be used as a mixing circuit.

[Explanation of symbols]

 1, 2 input terminal 3, 4 low noise amplifier (LNA) 5, 6 MMIC 7 local oscillator 8, 9 intermediate frequency amplifier (IFA) 10, 11 output terminal 12 Y-type power divider 5a, 6a signal input pin 5b , 6b Signal output pins 5c, 6d DC power supply pins 5d, 6c Local oscillation input pins

Claims (2)

(57) [Claims] 1. A two-output low-noise converter circuit for converting a horizontal and vertical polarization signal received by a receiving antenna into an intermediate frequency signal and outputting the intermediate frequency signal, wherein the horizontal and vertical polarization signals are converted to an intermediate frequency signal. First and second microwave semiconductor integrated circuits including a mixer element, a local oscillator for supplying a local oscillation signal to the first and second microwave semiconductor integrated circuits, a local oscillator, and the first and second microwave oscillators. And a Y-shape power divider for connecting the microwave semiconductor integrated circuit to the local oscillator. The first and second semiconductor integrated circuits are symmetrically positioned with respect to the local oscillator via the Y-shape power splitter. A low-noise converter circuit having different pin arrangements so as to be arranged. 2. The first and second semiconductor integrated circuits both have a local oscillation signal input pin on the Y-shape power divider side, and are respectively connected to the Y-shape power splitter via capacitors. The low noise converter circuit according to claim 1, wherein