KR102078052B1 - Apparatus for stabiling flatness using a variable resistor - Google Patents

Abstract

Disclosed is a flatness stabilization apparatus using a variable resistor which is inserted between a band-pass filter of a communication system and a power amplifier to stabilize the flatness of an output signal. The flatness stabilization apparatus comprises: a forced matching resistance unit which performs impedance matching between an input terminal, wherein the input terminal is a rear end of the band-pass filter, and an output end, wherein the output end is a front end of the power amplifier; a directionality determination unit which is connected to the forced matching resistance unit to determine the directionality of the frequency characteristics of a passband and the range of the signal strength of the passband; a flatness adjustment unit which includes a variable resistor for varying a slope of the frequency characteristics of the passband within the range of the signal strength of the passband that is determined by the directionality determination unit; a resonator circuit unit which determines a frequency at which a loss value of the passband becomes minimum; and a matching unit which performs impedance matching between a first part consisting of the forced matching resistance unit, the directionality determination unit, and the flatness adjustment unit and a second part consisting of the resonator circuit unit.

Description

Flatness stabilization device using variable resistor {APPARATUS FOR STABILING FLATNESS USING A VARIABLE RESISTOR}

The present invention relates to a device for stabilizing flatness inserted in a communication system, and more particularly, to a flatness stabilization device using a variable resistor that is adaptable to various frequency characteristics of a communication system.

Analog filters, which are essential for improving the efficiency of using limited frequency resources in communication systems, are implemented using passive elements, and these analog filters generally use resonant structures such as dielectric resonators and LC resonators. The low pass filter, a low pass filter, a high pass filter, a band pass filter, and a band reject filter are implemented.

In implementing these analog filters, all the filters are designed with ripple and flatness in consideration of the frequency characteristics of the pass frequency band, and the flatness is adapted to the user's requirements or the frequency characteristics in the communication system to be applied. Optimization is a big constraint in the implementation of the filter.

In particular, in the current 4G environment, since the frequency band used is not as wide as that of 5G, flatness is not so much a problem, but in the 5G environment, due to the wide frequency band, the flatness is a big issue.

For example, as illustrated in FIG. 1, in the case of a band pass filter, a sudden flatness change occurs in the vicinity of a used frequency band (a) and an unused frequency band (b), and an arc shape in which the insertion loss is convex upward. Will be achieved. Such a sudden change in flatness not only changes the communication quality for each frequency but also causes power loss.

To solve this problem, a method of improving flatness by adding a plurality of analog filters as an analog filter is also used. For example, as shown in (a) of FIG. 2, in the case of a band pass filter, filters having two bands corresponding to the band of the filter are physically arranged so that communication signals pass sequentially, or (b) of FIG. By arranging three filters arranged in sequence as shown in Fig. 2), the communication signals pass sequentially, thereby improving flatness as shown in FIG. 2 (c).

However, in the conventional flatness improvement method of arranging a plurality of filters, the reflection loss characteristics are deteriorated, resulting in power loss. In addition, the use of a plurality of filters, there is a problem that leads to an increase in the overall volume or cost of the filter. In addition, in the conventional flatness improvement method, variations in capacitance and inductance components included in the plurality of filters in the pass frequency band of the entire filter, that is, the impedance components included in the plurality of filters, are not constant. Therefore, it is difficult to predict the change of impedance, and there is a problem that a wide range of impedance change occurs according to the band of the filter that the user wants to use for each frequency characteristic. In this case, there is a problem that the size and manufacturing cost of the entire filter is further increased.

In addition, although the conventional analog filter shows a difference according to the environment of the communication system, there is a disadvantage that a sudden flatness change occurs in the frequency band used and the frequency band not used, and the frequency with the same communication system over time. Since the characteristics are also changed, the first inserted resonator must be continuously replaced to improve the flatness, and thus, there is a problem that also causes difficulty in work or a cost increase.

Korea Patent Registration No. 10-1735353 International Publication WO 02/35716 A2 (2002. 05. 02.) Japanese Patent Laid-Open No. 2005-286893 (October 13, 2005)

The problem to be solved by the present invention is to provide a flatness stabilization apparatus using a variable resistance of a new concept that can solve the problem of degradation of the reflection loss characteristics while improving the flatness of the filter.

Another problem to be solved by the present invention is to provide a flatness stabilization apparatus using a variable resistor to minimize the change in impedance in the pass frequency band.

Another problem to be solved by the present invention is that it is necessary to physically replace the existing resonator when the flatness needs to be improved by changing the frequency characteristic in the communication system environment using a conventional analog filter. It is to provide a flatness stabilization device using a variable resistor, which can reduce the difficulty of work or increase in cost.

Another problem to be solved by the present invention is to provide a flatness stabilization apparatus using a variable resistor, which can reduce the size of the filter and reduce the rise in manufacturing cost.

In accordance with an aspect of the present invention for solving the above problems, a flatness stabilization apparatus using a variable resistor is inserted between the bandpass filter and the power amplifier of the communication system to stabilize the flatness of the output signal, the input stage-the An input is a rear end of the band pass filter-and an output end-the output is a front end of the power amplifier-and a forced matching resistor for impedance matching between the forced matching resistor and a frequency characteristic of the pass band. A direction determining unit for determining the directionality of the pass band and determining a range of signal strength of the pass band, and varying the slope of the frequency characteristic of the pass band within a range of signal strength of the pass band determined by the directional determiner And a flatness control unit including a variable resistor for determining the loss minimum frequency of the pass band. And a matching part for impedance matching between the resonator circuit part, the first part including the forced matching resistor part, the directional determination part and the flatness adjusting part, and the second part consisting of the resonator circuit part. It is done.

The forced matching resistor unit may include a first forced matching resistor and a second forced matching resistor connected in series between the input terminal and the output terminal, and the directional determination unit may include the first forced matching resistor and the first forced matching resistor. The first forced matching resistor, the second forced matching resistor, and the directional determination unit may form a T-shaped circuit connected to an intermediate node of the second forced matching resistor.

According to one embodiment, the directional determination unit includes a directional determination capacitor for making the directionality of the frequency characteristic of the pass band to show a right upward.

According to one embodiment, the directional determination unit includes a directional determination inductor for causing the directionality of the frequency characteristic of the pass band to show the left upward.

According to an embodiment, the flatness adjusting unit, the matching unit and the resonator circuit unit are sequentially connected in series.

In accordance with another aspect of the present invention for solving the above problems, a flatness stabilization apparatus using a variable resistor is inserted between the band pass filter and the power amplifier of the communication system to stabilize the flatness of the output signal, the input stage-the An input is a rear end of the band pass filter, and an output stage, the output is a front end of the power amplifier, and a forced matching resistor for impedance matching, and connected to the forced matching resistor to determine the frequency characteristics of the pass band. A right upward directional circuit portion for directing directionality and a left upward directional circuit portion connected to the forced matching resistor part for directing the directionality of the frequency characteristic of the pass band to show a left upward direction; With the circuit part, the frequency characteristic of the pass band is displayed as arc shape. In addition, the right upward directional circuit unit, the flatness control unit including a directional determination capacitor for making the directionality of the frequency characteristics of the pass band showing a right upward direction, and a variable resistor for varying the slope of the frequency characteristics of the pass band. And a first resonator circuit portion for determining a first loss minimum frequency of the pass band, and a first impedance matching portion for impedance matching between the first resonator circuit portion and the remaining circuit portions in the right upward directional circuit portion. The upward directional circuit section includes a directional decision inductor for causing the directionality of the frequency characteristic of the pass band to be left upward, a second resonator circuit section for determining a second loss minimum frequency of the pass band, and the second resonator circuit section. And the impedance between the remaining circuit portions in the left upward directional circuit portion Claim 2 is characterized in that it comprises an impedance matching section for matching the scan.

According to one embodiment, the range of the signal strength of the pass band is determined by the directional decision capacitor or the directional decision inductor, and the variable resistance of the flatness control unit is determined by the directional decision capacitor or the directional decision inductor. The slope of the frequency characteristic of the pass band is varied within the range of signal strength of the pass band.

According to one embodiment, the flatness stabilization apparatus using the variable resistor, the first forced matching resistor and the second forced matching resistor connected in series between the input terminal and the output terminal, And a forced matching inductor connected in series between a first forced matching resistor and the second forced matching resistor, wherein the right-up directional circuit portion includes a first node and the second forced matching between the first forced matching resistor and the forced matching inductor. Connected in series to any one of a second node between a resistor and the forced matching inductor, wherein the left upward directional circuit portion is serially connected to a node to which the right upward directional circuit portion of the first node and the second node is not connected; Connected.

The present invention provides an flatness stabilization apparatus using a variable resistor, thereby improving the flatness of the filter, and has the effect of solving the problem of lowering the reflection loss characteristics.

In addition, the present invention has an effect of minimizing the change in impedance in the pass frequency band by providing a flatness stabilization device using a variable resistor.

In addition, the present invention provides a flatness stabilization device using a variable resistor, when the flatness is improved in accordance with the change in frequency characteristics in a communication system environment using a conventional analog filter to physically replace the existing resonator inserted Since the work is required, this can reduce the difficulty of work or the increase in cost. In addition, the present invention has the effect of reducing the size of the filter.

1 is a view for explaining the change in flatness of a conventional analog filter,
2 is a view for explaining a method for stabilizing flatness in a conventional communication system,
3 is a block diagram showing a state in which a matching circuit for impedance matching is inserted between a conventional communication system and a power amplifier,
4 is a basic equivalent circuit of the resonator,
5 is a view for explaining the improvement of the flatness by the flatness stabilization device according to an embodiment of the present invention, in particular to explain the basic content of the passband characteristics of the form inclined to the left and right,
6 is a graph showing passband characteristics without applying the flatness stabilization apparatus according to an embodiment of the present invention, (a) is a passband characteristic inclined to the right, and (b) is inclined to the left True passband characteristics, (c) is a graph showing passband characteristics inclined in a right and left combination,
FIG. 7 is a block diagram of a state in which a flatness stabilization device (flatness control unit 100) is inserted between a rear end of a band pass filter of the communication system 10 and the power amplifier 30 according to an embodiment of the present invention.
8 is a block diagram of the flatness stabilization device 100 according to an embodiment of the present invention,
9 shows an example of a specific equivalent circuit diagram of the flatness stabilization apparatus 100 according to an embodiment of the present invention.
FIG. 10 is a schematic diagram for describing a passband characteristic when the flatness stabilization apparatus of FIG. 9 is applied;
FIG. 11 illustrates a case in which the resistance value of the variable resistor Rt is reduced to a minimum as a pass band characteristic corresponding to FIG. 10B in the application of the flatness stabilization apparatus of FIG. 9 (a) and the variable resistor Rt. (B) is a graph showing the passband characteristics when the resistance value is raised to the maximum,
12 shows another example of a specific equivalent circuit diagram of the flatness stabilization apparatus 100 according to an embodiment of the present invention.
FIG. 13 is a schematic diagram for describing a passband characteristic when the flatness stabilization apparatus of FIG. 12 is applied;
FIG. 14 illustrates a case in which the resistance value of the variable resistor Rt is reduced to a minimum as a pass band characteristic corresponding to FIG. 13B in the application of the flatness stabilization apparatus of FIG. 12 (a) and the variable resistor Rt. (B) is a graph showing the passband characteristics when the resistance value is raised to the maximum,
15 is a block diagram of the flatness stabilization apparatus 200 according to another embodiment of the present invention,
16 is a specific equivalent circuit diagram of an equivalent circuit diagram of the flatness stabilization apparatus 200 according to another embodiment of the present invention.
17 is a schematic diagram illustrating a passband characteristic when the flatness stabilization apparatus of FIG. 16 is applied;
FIG. 18 illustrates the passage of the case where the resistance value of the variable resistor Rt is minimized (a) and the resistance value of the variable resistor Rt is maximum (b) when the flatness stabilization device of FIG. 16 is applied. A graph showing band characteristics.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings. It is to be noted that the accompanying drawings and embodiments are simplified and illustrated with the intention to facilitate the understanding of the present invention by those skilled in the art. In addition, it should be noted that the passband frequency characteristics in the drawings (particularly, FIGS. 1, 2, 5, 10, 13, and 17) are exaggerated or simplified for convenience of description.

4 shows the basic equivalent circuits of a resonator inserted into a communication system. As shown in Fig. 4, the resonator can be basically equivalent circuited into passive elements of resistor R, inductor L and capacitor C, and RLC series (a), RLC-parallel (b) , Or any suitable combination thereof. These resonant circuits produce the proper resonant frequency needed.

5 is a view for explaining the improvement of the flatness by the flatness stabilization device according to an embodiment of the present invention, in particular the passband frequency characteristics of the form inclined to the left and right, that is, the flatness stabilization device of the present invention (flatness) FIG. 10 is a diagram for briefly explaining basic contents of a passband frequency characteristic when the controller is not applied. Each of the case where the passband frequency characteristic is left upward, right upward, and a combination of left upward and right upward will be described in more detail later.

In general, in a communication system, flatness means a uniform degree of a loss value corresponding to a value of each frequency in a pass frequency band, and accordingly. Improving flatness means reducing the mutual difference between the loss values corresponding to the values of the frequencies in the pass frequency band, and flatness is also used in this sense.

 Referring to FIG. 5, the passband frequency characteristics of the signal passing through the bandpass filter in the communication system are convex downward as a combination of left upward and right upward (left side of FIG. 5A). In order to stabilize the flatness of the passband frequency characteristics, by inserting the flatness stabilization apparatus (flatness control unit) of the present invention showing the passband frequency characteristics as shown on the right side of FIG. As shown in turn b) and in FIG. 5C, the flatness is stabilized. That is, by inserting the flatness stabilization device showing a frequency characteristic opposite to the pass band frequency characteristics when the flatness stabilization device (flatness adjustment unit) of the present invention is not applied, finally, as shown in FIG. The stabilized flatness can be realized.

6 is a graph illustrating passband characteristics when a flatness stabilization device is not applied according to an embodiment of the present invention. Those (g1, g2, g3) shown in purple in each of FIGS. 6 (a), (b) and (c) simulate the passband characteristics in the unapplied state of the present invention. Specifically, (a) is the frequency characteristic of the passband inclined to the right (hereinafter abbreviated as 'upward directional'), and (b) is inclined to the left (hereinafter abbreviated as 'upward directional') (C) is a graph showing the frequency characteristics of a pass band inclined by a right and left combination (hereinafter abbreviated as 'complex directionality'). Accordingly, the flatness stabilizing device of the present invention stabilizes flatness without, for example, physical replacement of the whole flatness stabilizing device by appropriately canceling the directionality corresponding to each of these cases. You can.

7 is a block diagram of a state in which a flatness stabilization device (flatness control unit 100) according to an embodiment of the present invention is inserted between a rear end of a band pass filter of the communication system 10 and the power amplifier 30. In FIG. 7, the communication system 10 is briefly represented as a low noise amplifier and a band pass filter for convenience, and the power amplifier 30 is separately indicated at the end, but the power amplifier 30 is also used in the communication system. Included configuration. In addition, in the communication system 10, the passband frequency characteristic is also affected by other components in the communication system 10, but is basically the most affected by the bandpass filter, so for convenience the bandpass filter Refers to the passband frequency characteristic after passing through.

Referring to FIG. 7, the flatness stabilization apparatus 100 of the present invention is inserted between the power amplifiers 30 while being the rear end of the band pass filter, and serves to stabilize the flatness in the pass band frequency characteristics.

8 is a block diagram of the flatness stabilization device 100 according to an embodiment of the present invention, Figure 9 shows an example of a specific equivalent circuit diagram of the flatness stabilization device 100 according to an embodiment of the present invention FIG. 10 is a schematic diagram for describing a passband characteristic when the flatness stabilization apparatus of FIG. 9 is applied, and FIG. 11 corresponds to FIG. 10 (b) in applying the flatness stabilization apparatus of FIG. 9. As the pass band characteristics, the graph shows the pass band characteristics when the resistance value of the variable resistor Rt is reduced to the minimum (a) and the resistance value of the variable resistor Rt is raised to the maximum (b).

First, referring to FIG. 8, the flatness stabilization apparatus of the present invention includes a matching resistor unit 110, a directional determination unit 120, a flatness control unit 130, a resonator circuit unit 150, and a matching unit 140. ). The direction determining unit 120, the flatness adjusting unit 130, the matching unit 140, and the resonator circuit unit 150 are sequentially connected in this order.

The forced matching resistor unit 110 is a component for impedance matching between the input terminal IN and the output terminal OUT. The forced matching resistor unit 110 is for forcibly matching the input / output in the flatness stabilization apparatus 100 of the present invention, and thus, there is no need to insert a separate filter and a matching circuit for impedance matching of the input / output terminals as in the prior art. There is an advantage.

The directional determination unit 120 is connected to the forced matching resistor unit 110 to determine the directionality of the frequency characteristics of the pass band and to determine the range of signal strength of the pass band. The directionality of the frequency characteristic of the pass band is determined by one of the right upward direction, the left upward direction and the complex direction by means of a capacitor, an inductor or a suitable combination thereof, which is described in more detail later. The range of signal strength of the pass band means the strength (or loss, also expressed in units of dB) of the signal represented by the y-axis in the drawings.

The flatness control unit 130 is a component for varying the slope of the frequency characteristic of the pass band within the range of the signal strength of the pass band determined by the directional determination unit 120, and includes a variable resistor therefor.

The resonator circuit unit 150 is a component for determining the loss minimum frequency of the pass band (the maximum frequency of the signal strength). The resonator circuit 150 may be implemented in series, in parallel, or a suitable combination of inductors and capacitors.

The matching unit 140 may include a second part including the resonator circuit unit 150 and a circuit unit other than the second part, that is, the forced matching resistor unit 110, the directional determination unit 120, and the flatness adjusting unit 130. It is a component for self impedance matching with 2 parts.

Referring to FIG. 9 together with FIG. 8, the forced matching resistor unit 110 may include a first forced matching resistor R11 and a second forced matching resistor R12 connected in series between the input terminal IN and the output terminal OUT. ).

The directional determination unit 120 is connected to an intermediate node between the first forced matching resistor R11 and the second forced matching resistor R12 to form the first forced matching resistor R11, the second forced matching resistor R12, and the directionality. The determination unit 120 forms a T-shaped circuit.

 9 to 11 are applied when the frequency characteristic of the pass band indicates the left upward direction when the flatness stabilization device 100 of the present invention is not applied, and the inserted flatness stabilization device 100 shows the right upward direction. It should be configured to Therefore, the directional determination unit 120 includes a directional determination capacitor C11 in order to make the directionality of the frequency characteristic of the pass band show a right upward direction. Referring to FIG. 9, a flatness stabilization device having a frequency characteristic of a pass band showing a right upward direction will be described in detail. The first forced matching resistor R11 and the second forced matching resistor R12 may include an input terminal IN and an output terminal. The anti-determination capacitor C11 is connected to an intermediate node of the first forced matching resistor R11 and the second forced matching resistor R12 by being connected in series between OUTs. In addition, the flatness adjusting unit 130 connected in series to the directional determination capacitor C11 may be configured such that the fixed resistor R13 and the variable resistor Rt are connected in parallel. The fixed resistor R13 basically plays a role of determining the amplitude of signal strength even in a conventional matching circuit or a resonator circuit. However, since the slope of the frequency characteristic determined by the fixed resistor R13 is single, the fixed resistor ( Only R13) makes it difficult to cope with various frequency characteristics of the pass band. Therefore, by inserting the variable resistor Rt to adjust the resistance value, it is possible to vary the slope of the frequency characteristic of the pass band within the range of the signal strength of the pass band determined by the directional determination unit 120, thereby providing a communication system. It can correspond to various frequency characteristics of.

The matching capacitor C12 constituting the matching unit 140 serves to match the impedance between the upper circuits (first part) and the lower resonator circuit units 150 (C13 and L11). The resonator circuit unit 150 is composed of the L-C parallel circuits of the capacitor C13 and the inductor L11, but may be variously implemented in series or a combination of series and parallel as necessary to determine the loss minimum frequency. Here, the loss minimum frequency is a frequency corresponding to the far right in Fig. 10B.

As shown in (a) of FIG. 10, when the frequency characteristic of the pass band indicates left upward directionality when the flatness stabilization device 100 of the present invention is not applied, the reverse of the opposite direction is illustrated in FIG. It is possible to stabilize the flatness as shown in FIG. 10C through the configuration (for example, the circuit diagram of FIG. 9) showing the frequency characteristic of the upward direction.

As shown in FIG. 11, in the case of implementing the flatness stabilization device as shown in the circuit diagram of FIG. 9, when the resistance value of the variable resistor Rt is minimized, as shown in (a), it is relatively gentle. (G11), and when the passband frequency characteristic of the communication system exhibits a relatively gentle leftward directionality, as shown in (a), the variable resistor Rt is lowered to a minimum value to stabilize flatness. Can be. On the contrary, when the resistance value of the variable resistor Rt is raised to the maximum, as shown in (b), it shows a right upward direction with a sharp slope (g12). Thus, the passband frequency characteristic of the communication system is relatively sharp. When indicating the upward direction, the flatness can be stabilized by increasing the resistance value of the variable resistor Rt close to the maximum value as in (b). The range of the minimum and maximum values of the resistance value of the variable resistor Rt may be predetermined according to the variable resistor Rt used.

12 to 14 are applied when the frequency characteristics of the pass band when the non-applied flatness stabilization device 100 of the present invention exhibits a right upward direction, the inserted flatness stabilization device 100 shows a left upward direction. It should be configured to Therefore, the directional decision unit 120 includes a directional decision inductor L21 in order to make the directionality of the frequency characteristic of the pass band show the upward direction.

Referring to FIG. 12, a flatness stabilization device having a frequency characteristic of a pass band showing a left upward direction is described in detail. The first forced matching resistor R21 and the second forced matching resistor R22 may be connected to the input terminal IN. The anti-determination determination inductor L11 is connected to the intermediate node between the first forced matching resistor R21 and the second forced matching resistor R22 by being connected in series between the output terminals OUT. In addition, the flatness adjusting unit 130 connected in series to the directional inductor L11 may be configured such that the fixed resistor R23 and the variable resistor Rt are connected in parallel. As mentioned above, the fixed resistor R23 basically serves to determine the amplitude of the signal strength even in the existing matching circuit or the resonator circuit, but the slope of the frequency characteristic determined by the fixed resistor R23 is Since it is single, it is difficult to cope with various frequency characteristics of the pass band with only the fixed resistor R23. Therefore, by inserting the variable resistor Rt to adjust the resistance value, it is possible to vary the slope of the frequency characteristic of the pass band within the range of the signal strength of the pass band determined by the directional determination unit 120, thereby providing a communication system. It can correspond to various frequency characteristics of.

The matching capacitor C21 constituting the matching unit 140 serves to match impedance between upper circuits (first part) and lower resonator circuit units 150 (C22 and L22). The resonator circuit unit 150 is composed of the L-C parallel circuit of the capacitor C22 and the inductor L22, but may be variously implemented in series or a combination of series and parallel as necessary to determine the loss minimum frequency. Here, the loss minimum frequency is a frequency corresponding to the far left in Fig. 13B.

As shown in (a) of FIG. 13, when the frequency characteristic of the pass band indicates a right upward direction when the flatness stabilization apparatus 100 of the present invention is not applied, the opposite of left as shown in FIG. It is possible to stabilize the flatness as shown in FIG. 13C through the configuration (for example, the circuit diagram of FIG. 12) showing the upward direction of the frequency characteristic.

As shown in FIG. 14, in the case of implementing the flatness stabilization device as shown in the circuit diagram of FIG. 12, when the resistance value of the variable resistor Rt is minimized, as shown in (a), it is relatively gentle. (G21), and when the passband frequency characteristic of the communication system exhibits a relatively gentle rightward directionality, as in (a), the variable resistor Rt is lowered to a minimum value to stabilize flatness. Can be. In contrast, when the resistance value of the variable resistor Rt is raised to the maximum, as shown in (b), it exhibits a left upward directionality with a sharp slope, so that the passband frequency characteristic of the communication system has a relatively sharp upward upward directionality. As shown in (b), the flatness can be stabilized by increasing the resistance value of the variable resistor Rt close to the maximum value. The range of the minimum and maximum values of the resistance value of the variable resistor Rt may be predetermined according to the variable resistor Rt used.

15 to 18 illustrate a flatness stabilization apparatus 200 using a variable resistor, which is inserted between a band pass filter and a power amplifier of a communication system to stabilize flatness of an output signal according to another embodiment of the present invention. It is a figure for demonstrating.

15 to 18, flatness can be stabilized by applying to a case where the passband frequency characteristic of the communication system represents a complex directionality in which the left upward direction and the right upward direction are combined.

First, referring to FIG. 15, the flatness stabilization apparatus 200 using the variable resistor of the present invention includes a forced matching resistor unit 210 and forced matching for impedance matching between the input terminal IN and the output terminal OUT. It is connected to the resistor unit 210, and connected to the right-up directional circuit section 260a and the forced matching resistor unit 210 so that the directionality of the frequency characteristics of the pass band indicates the right direction, the directionality of the frequency characteristics of the pass band A left upward directional circuit portion 260b for indicating left upward directionality. The right upward directional circuit portion 260a and the left upward directional circuit portion 260b work together so that the characteristics of the frequency characteristics of the pass band exhibit an arc shape. For example, when the frequency characteristic of the pass band when the flatness stabilization apparatus of the present invention is not applied is convex upward, the flatness stabilization apparatus of the present invention is configured to exhibit the pass band frequency characteristic of the arc convex downward. If so, the flatness of the final output signal can be stabilized.

The right-up directional circuit section 260a is a flat panel including a directional decision capacitor C31 for causing the directivity of the frequency characteristic of the pass band to show the right direction, and a variable resistor Rt for varying the slope of the frequency characteristic of the pass band. The degree adjusting part R33 // RT, the first resonator circuit parts C34 and L32 for determining the first loss minimum frequency of the pass band, the first resonator circuit parts C34 and L32 and the right upward directional circuit part 260a. And a first impedance matching unit C32 for impedance matching between the remaining circuit units C31, R33, and Rt in the circuit. Although the first resonator circuits C34 and L32 are configured as L-C parallel circuits, other types of circuits are possible and may be configured as circuits suitable for determining the first loss minimum frequency required. In addition, the first impedance matching unit C32 is composed of one capacitor.

The left upward directional circuit section 260b includes a directional determination inductor L32 for causing the directionality of the frequency characteristic of the pass band to show left upward, and a second resonator circuit section C35 for determining the second loss minimum frequency of the pass band. // L33 and a second impedance matching part C33 for impedance matching between the second resonator circuit parts C35 and L33 and the remaining circuit parts L32 and R34 in the left upward directional circuit part 260b. Although the second resonator circuit parts C35 and L33 are configured as L-C parallel circuits, other types of circuits are possible and may be configured as circuits suitable for determining the required second loss minimum frequency. In addition, the second impedance matching unit C33 includes one capacitor.

Here, the range of the signal strength (or loss, dB) of the pass band may be selectively determined by the directional decision capacitor C31 and the directional decision inductor L32, and in the case of the variable resistor Rt constituting the flatness controller. When the resistance value is appropriately changed in correspondence with the frequency characteristic of the communication system, the frequency characteristic of the pass band within the range of signal strength of the pass band determined by the directional decision capacitor C31 and the directional decision inductor L32 is determined. The slope of can be varied.

In addition, as shown in FIG. 15, the flatness stabilization apparatus 200 using the variable resistor of the present invention may include a first forced matching resistor R31 connected in series between an input terminal IN and an output terminal OUT. It includes a second forced matching resistor (R32), and includes a forced matching inductor (L31) connected in series between the first forced matching resistor (R31) and the second forced matching resistor (R32). In addition, the right upward directional circuit unit 260a includes a first node between the first forced matching resistor R31 and the forced matching inductor L31 and a second node between the second forced matching resistor R32 and the forced matching inductor L31. The left upward directional circuit 260b may be serially connected to one of the first and second nodes to which the right upward directional circuit 260a is not connected.

As shown in (a) of FIG. 17, when the frequency characteristic of the pass band exhibits an upwardly convex arc-like frequency characteristic when the flatness stabilization apparatus 200 of the present invention is not applied, as shown in FIG. 17 (b). The flatness can be stabilized as shown in FIG. 17C through the configuration (for example, the circuit diagram of FIG. 16) showing the frequency characteristics of the convex downwardly convex shape.

As shown in FIG. 18, when the flatness stabilization device 200 is implemented as shown in the circuit diagram of FIG. 16, when the resistance value of the variable resistor Rt is minimized, as shown in (a) (G31) When the passband frequency characteristic of the communication system exhibits a relatively gentle convex frequency characteristic, the variable resistance as in (a) The flatness can be stabilized by lowering (Rt) close to the minimum value. On the other hand, when the resistance value of the variable resistor Rt is raised to the maximum, as shown in (b), the arc-shaped frequency characteristics are rapidly convex, and thus, the passband frequency characteristics of the communication system are relatively high. When exhibiting an arc-shaped frequency characteristic that is suddenly convex, flatness can be stabilized by increasing the resistance of the variable resistor Rt close to the maximum value as in (b). The range of the minimum and maximum values of the resistance value of the variable resistor Rt may be predetermined according to the variable resistor Rt used, and the range controlled by the variable resistor Rt may be determined as described above. It is limited to the range of signal strength of the pass band determined by the capacitor C31 (Fig. 16) or the directional decision inductor L32 (Fig. 16).

The flatness stabilization apparatus using the variable resistor of this invention was demonstrated above. Flatness stabilization apparatus using a variable resistor of the present invention has the advantage that can be stabilized by adjusting the resistance value of the variable resistor without periodically replacing or inserting a separate matching circuit or resonator. In other words, by adjusting the resistance value of the variable resistor, the shape of the inclination is realized in the desired shape (left upward direction, right upward direction, complex direction), thereby stabilizing flatness corresponding to the passband frequency characteristics without physical replacement work. You can. In addition, by securing a minimum refinement ratio, it is easy to match impedance in a communication system, and can be used consistently.

As mentioned above, the flatness stabilization apparatus using the variable resistance of the present invention is expected to have a great effect in the cost reduction or ease of flatness stabilization in a 5G environment with a wider frequency bandwidth than 4G.

100: flatness stabilization device using a variable resistor
110: matching resistor
120: directional determination unit
130: flatness adjustment unit
140: matching unit
150: resonator circuit portion
160a: right upward directional circuit portion
160b: left upward directional circuit portion

Claims (8)

A flatness stabilization apparatus using a variable resistor, which is inserted between a band pass filter of a communication system and a power amplifier to stabilize flatness of an output signal,
A forced matching resistor section for impedance matching between an input stage, the input being a rear stage of the band pass filter, and the output stage, the output being a front end of the power amplifier;
Directional decision unit for determining the directionality of the frequency characteristics of the pass band-connected to the forced matching resistor unit-The frequency characteristics of the pass band is expressed by the frequency of the pass band as the X axis and the signal strength for each frequency as the Y axis The directionality of the frequency characteristic of the pass band is a combination of a left upward direction in which the graph is tilted to the right, an upward upward direction in which the graph is tilted to the left, and a graph in which the graph is tilted to the right and to the left. One of complex directionality;
A flatness control unit including a variable resistor for changing a slope in the frequency characteristic of the pass band;
A resonator circuit portion for determining the loss minimum frequency of the pass band; And
And a matching unit for impedance matching between the first part consisting of the forced matching resistor part, the directional determination part, and the flatness adjusting part, and the second part consisting of the resonator circuit part. Flatness stabilization device using a variable resistor.
The method according to claim 1,
The forced matching resistor unit may include a first forced matching resistor and a second forced matching resistor connected in series between the input terminal and the output terminal, and the directional determination unit may include the first forced matching resistor and the second forced matching resistor. Connected to an intermediate node, wherein the first forced matching resistor, the second forced matching resistor, and the directional determination unit form a T-shaped circuit.
The method according to claim 2,
And the directional determination unit includes a directional determination capacitor for directing the directionality of the frequency characteristic of the pass band to show the upward directionality.
The method according to claim 2,
And the directional determination unit includes a directional determination inductor for causing the directionality of the frequency characteristic of the pass band to show a left upward directionality.
The method according to claim 2,
Flatness stabilization apparatus using a variable resistor, characterized in that the flatness control unit, the matching unit and the resonator circuit unit is connected in series.
A flatness stabilization apparatus using a variable resistor, which is inserted between a band pass filter of a communication system and a power amplifier to stabilize flatness of an output signal,
A forced matching resistor section for impedance matching between an input stage, the input being a rear stage of the band pass filter, and the output stage, the output being a front end of the power amplifier;
The frequency characteristic of the pass band connected to the forced matching resistor unit-The frequency characteristic of the pass band is a graph in which the frequency of the pass band is expressed as the X-axis and the signal strength for each frequency as the Y-axis. A rightward directional circuit unit for making it visible; And
A left upward directional circuit part connected to the forced matching resistor to show a left upward direction in which the frequency characteristic of the pass band is inclined to the right-the left upward directional circuit part together with the right upward directional circuit part and the frequency of the pass band; Make the characteristic exhibit an arc shape; Including;
The right upward directional circuit portion,
A flatness adjusting unit including a directional determination capacitor for causing the frequency characteristic of the pass band to show the upward directionality, a variable resistor for varying the slope of the frequency characteristic of the pass band, and a first loss of the pass band. A first resonator circuit portion for determining a minimum value frequency, and a first impedance matching portion for impedance matching between the first resonator circuit portion and the remaining circuit portions in the right upward directional circuit portion,
The left upward directional circuit portion,
A directional determination inductor for causing the frequency characteristic of the pass band to exhibit the left upward directionality, a second resonator circuit portion for determining a second loss minimum frequency of the pass band, the second resonator circuit portion and the left upward directionality And a second impedance matching part for impedance matching between the remaining circuit parts in the circuit part.
The method according to claim 6,
The variable resistance of the flatness control unit, characterized in that for varying the slope in the frequency characteristic of the pass band, flatness stabilization apparatus using a variable resistor.
The flatness stabilization apparatus using the variable resistor according to claim 6,
A first forced matching resistor and a second forced matching resistor connected in series between the input terminal and the output terminal, and a forced matching inductor connected in series between the first forced matching resistor and the second forced matching resistor; ,
The rightward directional circuit unit is connected in series to any one of a first node between the first forced matching resistor and the forced matching inductor and a second node between the second forced matching resistor and the forced matching inductor; And a left upward directional circuit unit is connected in series to a node of the first node and the second node to which the right upward directional circuit unit is not connected.

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