KR100707826B1 - Multi band pass filter - Google Patents

Abstract

The multi-band pass filter according to the present invention implements a low pass filter and a high pass filter unlike the conventional method using a band pass filter in a row, and then implements the low pass filter and the high pass filter in a row again in the pass band. Implementing the desired number of bandpass filters can not only solve the impedance matching problem, but it is also easy to implement the desired number of passbands, and notches the lowpass of the lowpass and highpass filters. Therefore, the attenuation characteristic can be greatly improved, miniaturization, light weight, as well as excellent effect that can be mass-produced as a low cost product.

Description

Multiband Pass Filter {MULTI BAND PASS FILTER}

1 is a conceptual diagram showing a configuration and a pass band of a multi-band pass filter according to the prior art.

2 is a circuit diagram illustrating a multi-band pass filter according to the present invention.

3 is a conceptual diagram illustrating a pass band of a multi-band pass filter according to the present invention.

4A to 4D are characteristic graphs implemented by the multi-band pass filter according to the present invention.

5 is a block diagram for manufacturing a multi-band pass filter according to the present invention.

       ≡ * ≡ Explanation of symbols for the main parts of the drawing ≡ * ≡

10: input stage 20: first row left low pass filter

21: second row left low pass filter 22: second row left high pass filter

23: column 3 left high pass filter 30: column 1 right high pass filter

31: second column right low pass filter 32: second column right high pass filter

33: third row right low pass filter 40: notch

51: first output terminal 52: second output terminal

53: third output stage 54: fourth output stage

100: multi-band pass filter PCB: circuit board

L: Inductor C: Capacitor

S: Shield Case

The present invention relates to a multi-band pass filter, and more particularly, to a multi-band pass filter having a plurality of pass bands by implementing a plurality of low and high pass filters in the low pass and high pass.

In recent years, wireless mobile communication technology has been rapidly developed, and the main reason for this change can be found in the rapid development of signal processing technology, that is, modulation demodulation, and more efficient information in a limited frequency band. The reason for this is found in the software aspect that enables delivery and the hardware aspect that is the development of component technology.

More specifically, the filter technology among the parts technology is a technology that selects only a desired signal from a myriad of air waves and filters only a signal to be transmitted, and can be called the core of the parts technology. It is necessary to pay attention to the development of a multi-band pass filter having a plurality of pass bands.

1 is a conceptual diagram illustrating a configuration and a pass band of a multi-band pass filter 200 according to the prior art.

As shown in FIG. 1, the multi-band pass filter 200 which is currently used most often implements the band pass filters 81, 82, 83, and 84 in a row as many as the desired pass bands and unites the input stage 70 as one. It is presented as a binding type.

However, in the multi-band pass filter 200 according to the related art, impedance matching problems occur in the process of designing the band pass filters 81, 82, 83, and 84 in a row and tying the input terminals 70 together. The bandpass filter 81, 82, 83, 84 has a problem that the attenuation characteristic is particularly bad in the low band outside the passband due to the interference problem between each other, and also has a disadvantage that the size is also large.

For example, in the case of the conventional multi-band pass filter 200 having four band pass filters 81, 82, 83, and 84, each of the signals provided from one input terminal 70 as shown in FIG. It is configured to be directly output to the four outputs (91, 92, 93, 94) while being filtered through the band pass filter (81, 82, 83, 84).

However, such a conventional multi-band pass filter 200 divides the signal provided from one input terminal 70 into four pass bands and divides each band pass into respective output terminals 91, 92, 93, and 94. Due to the design of the filters 81, 82, 83, and 84 arranged in a horizontal row, 50 Ω matching is broken, which causes a problem in that the matching of the input stage 70 is extremely difficult.

That is, each of the band pass filters 81, 82, 83, and 84 constituting the conventional multi-band pass filter 200 is matched with an impedance of 50 Ω only in its pass band and has an infinite impedance outside the pass band. Although each of the band pass filters 81, 82, 83, 84 is 50Ω matched, the impedance seen from one input terminal 70 is in a state where the 50Ω match is broken, so that each of the band pass filters 81, 82, 83, 83, 84) there is a problem of changing the characteristics.

In this case, each bandpass filter (81, 82, 83, 84) must be adjusted again for impedance matching. However, if one bandpass filter (for example, 81) is adjusted, the remaining three bandpass filters 82, 83 are adjusted. , It affects the impedance of (84), so that it is extremely difficult to match the impedance of the band pass filter (81, 82, 83, 84), it takes a considerable time to manufacture the multi-band pass filter 200.

Also, the greater the number of passbands, the more difficult it is to match the impedance match, and when the impedance match is not correct, the bandpass filters 81, 82, 83, and 84 at the low band outside the passband by mutual interference. The attenuation characteristic of is leading to the problem of being particularly bad.

The present invention has been made to solve the above disadvantages, and its object is to implement a plurality of lowpass filters and highpass filters in the lowpass and highpass multiband pass having a plurality of passbands excellent in attenuation characteristics In providing a filter.

The present invention for achieving the above object,

A first column left low pass filter and a first column right high pass filter for passing a low band and a high band among signals provided from an input terminal,

A second column left low pass filter and a third column left high pass filter configured to pass a lower low band of the low band signal of the first column left low pass filter to the first output terminal;

A second column left high pass filter configured to pass an upper low band from a low band signal of the first column left low pass filter to a second output terminal;

A second column right low pass filter configured to pass a lower high band of the high band signal of the first column right high pass filter to a third output terminal;

The second configuration includes a second column right high pass filter and a third column right low pass filter which pass an upper high band of the high band signal of the first column right high pass filter and supply it to the fourth output terminal. It features.

Hereinafter, preferred embodiments of a multi-band pass filter according to the present invention will be described with reference to the drawings, and through these embodiments, the objects, features, and advantages of the present invention can be more easily understood.

2 is a circuit diagram illustrating a multi-band pass filter 100 according to the present invention, FIG. 3 is a conceptual diagram showing a pass band of the multi-band pass filter 100 according to the present invention, and FIG. 4 is a multi-band according to the present invention. Characteristic graph implemented by the pass filter 100.

In the drawings described in the present invention, the meaning of 50 to 260 MHz in relation to the conceptual diagram of FIG. 3 refers to a simple range of frequencies presented for easier understanding of the present invention, and also "first column left" and "first column right". The words such as are also presented for the technical understanding of the present invention is not particularly limited thereto, and the first output terminal 51 to the fourth output terminal 54 is also not particularly limited in number.

In the multi-band pass filter 100 according to the present invention, as shown in FIG. 2, the first column left low pass filter 20 and the first column passing through the low band and the high band, respectively, from the signal provided from the input terminal 10. A low band of 122.5 MHz or less shown in the first column of the conceptual diagram of FIG. 3 by the right high pass filter 30, and by these first column left low pass filter 20 and the first column right high pass filter 30 Signal and high-bandwidth signals greater than 172.5 MHz.

Preferably, the multi-band pass filter 100 according to the present invention passes the lower low band of the low-band signal of the first column left low pass filter 20 to supply the second column left low pass to the first output terminal 51. A pass filter 21 and a third column left high pass filter 23 are provided, and the upper pass of the low band signal of the first column left low pass filter 20 is supplied to the second output terminal 52. The second column left high pass filter 22 is included.

The second column left low pass filter 21 and the third column left high pass filter 23 which pass the lower low band from the low band signal of the first column left low pass filter 20 to the first output stage 51. ) Can supply the low-frequency low-band signal of 50 to 70 MHz (see FIG. 4A together), which is a combination of the second column and the third column, shown in the conceptual diagram of FIG. 3 to the first output terminal 51.

In addition, the second column left high pass filter 22 which passes the upper low band among the low band signals of the first column left low pass filter 20 and supplies it to the second output terminal 52 is shown in the conceptual diagram of FIG. 3. The upper low-band signal of 97.5-122.5 MHz (see FIG. 4B together), which is a combination of the first column and the second column, can be supplied to the second output terminal 52.

Furthermore, the multi-band pass filter 100 according to the present invention passes the lower high band of the high band signal of the first column right high pass filter 30 to supply the second column right low pass to the third output terminal 53. A second column right high pass filter 32 having a filter 31 and configured to pass an upper high band of the high band signal of the first column right high pass filter 30 to the fourth output terminal 54; And a three column right low pass filter 33.

A first column shown in the conceptual diagram of FIG. 3 by a second column right low pass filter 31 which passes a lower high band among the high band signals of the first column right high pass filter 30 and supplies it to the third output terminal 53. The lower high-band signal of 172.5 to 197.5 MHz (see FIG. 4C together), which is a combination of the column and the second column, can be supplied to the third output terminal 53.

Then, the second column right high pass filter 32 and the third column right low pass filter which pass an upper high band among the high band signals of the first column right high pass filter 30 and supply it to the fourth output terminal 54. By 33, the upper high-band signal of 240 to 260 MHz (see FIG. 4D together), which is a combination of the second column and the third column, shown in the conceptual diagram of FIG. 3 can be supplied to the fourth output terminal 54.

At this time, the first column left low pass filter 20, the second column left low pass filter 21, the second column left high pass filter 22, the third column left high pass filter 23, the first column right The high pass filter 30, the second row right low pass filter 31, the second row right high pass filter 32, or the third row right low pass filter 33 all have notches 40 for enhancing attenuation characteristics. Notch may be further included, and the notch 40 may further filter the signal quality of the input terminal 10 to be supplied to the first output terminal 51 to the fourth output terminal 54.

The multi-band pass filter 100 according to the present invention can be used for a mobile communication transmitting and receiving terminal, a repeater or a wireless communication system and the like, and a plurality of low pass in a row in each pass band for passing several instead of one pass band. By implementing a pass filter and a high pass filter, it is possible to complete a multi-band pass filter 100 of excellent quality having multiple pass bands.

That is, since a finer passband is implemented in the low band or the high band where the 50Ω match is started starting from one input terminal 10, the 50Ω match is not broken, and thus the first output terminal 51 shown in FIG. 50 to 70 MHz), the desired number as shown in the characteristic graphs of the second output stage (52; 97.5 to 122.5 MHz), the third output stage (53; 172.5 to 197.5 MHz) and the fourth output stage (54; 240 to 260 MHz); As many passbands as possible can be realized.

5 is a block diagram for manufacturing a multi-band pass filter 100 according to the present invention.

The first column left low pass filter 20, the second column left low pass filter 21, the second column left high pass filter 22, and the second column, which constitute the multi-band pass filter 100 according to the present invention. 3rd column left highpass filter 23, 1st column right highpass filter 30, 2nd column right lowpass filter 31, 2nd column right highpass filter 32 and 3rd column right lowpass filter 5 may be implemented as an inductor (L) and a capacitor (C) on the circuit board (PCB), as shown in Figure 5, if necessary to cover the shield case (S) to prevent the interference of the external circuit fabrication Can be.

As described above, the multi-band pass filter according to the present invention implements a low pass filter and a high pass filter unlike a conventional method using a band pass filter in a row, and then re-adds the low pass filter and the high pass filter within the pass band. Implementing the desired number of bandpass filters by implementing them in a row not only solves the problem of impedance matching, but it is also particularly easy to implement the desired number of passbands, and the lowpass of the lowpass filter and the highpass filter. Notch can greatly improve attenuation characteristics, and it has excellent effect that can be mass-produced with low cost as well as miniaturization and light weight.

As can be seen from the above object, configuration, and effect of the present invention, the present invention implements a plurality of low pass filters and high pass filters in each pass band, thereby completing a multi-band pass filter having high quality with multiple pass bands. The above is the biggest core technology, other changeable configurations can be understood as the number of various cases, the present invention includes all of the number of such changeable cases, and the interpretation of the claims are also equivalent.

Claims (3)

A first column left low pass filter 20 and a first column right high pass filter 30 which pass low and high bands, respectively, from a signal provided from the input terminal 10; The second column left low pass filter 21 and the third column left high pass filter configured to pass a lower low band among the low band signals of the first column left low pass filter 20 to be supplied to the first output terminal 51. 23) and, A second column left high pass filter 22 configured to pass an upper low band from the low band signal of the first column left low pass filter 20 to the second output terminal 52; A second column right low pass filter 31 which passes a lower high band from the high band signal of the first column right high pass filter 30 and supplies it to the third output terminal 53; The second column right high pass filter 32 and the third column right low pass filter which pass an upper high band among the high band signals of the first column right high pass filter 30 and supply it to the fourth output terminal 54 ( 33) multi-band pass filter 100, characterized in that comprises a. The method of claim 1, The first column left low pass filter 20, the second column left low pass filter 21, the second column left high pass filter 22, or the third column left high pass filter 23 enhance the attenuation characteristics. Multi-band pass filter 100, characterized in that it further comprises a notch (40). The method according to claim 1 or 2, The first column right high pass filter 30, the second column right low pass filter 31, the second column right high pass filter 32, or the third column right low pass filter 33 enhance the attenuation characteristics. Multi-band pass filter 100, characterized in that it further comprises a notch (40).

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