TWI751892B - Miniaturized bandpass filters - Google Patents

Abstract

The present invention mainly discloses a miniature bandpass filter, which comprises: a first resonance unit, a second resonance unit, a third resonance unit and a fourth resonance unit. Wherein, the first resonance unit, the second resonance unit, the third resonance unit and the fourth resonance unit are implemented in a main body. And, the main body includes a resonant substrate. In the present invention, the resonant substrate includes a first ground layer, and the first ground layer is connected with a first transmission layer to form a first connection portion. It should be noted that the top view shape of the first connecting portion is H-shape. With such a design, the miniature bandpass filter with the H-shaped connecting portion of the present invention has the advantages of improving the influence of the alignment offset and high stability compared with the conventional filter.

Description

Miniature Bandpass Filter

The present invention relates to the technical field of semiconductors and electronic components thereof, in particular to a miniature bandpass filter.

With the development of the technology and communication industry, the market and consumers demand for the filter to miniaturize its size and improve its noise rejection rate. Bandpass filter is a widely used component, and the microstrip line bandpass filter has the advantages of small size, light weight and high reliability.

It is easy to understand that as the miniaturization of the filter described above progresses, there will be an increased chance of dimensional or cutting errors in the manufacturing process. Among them, the comb-shaped band-pass filter is a band-pass structure with a wide stop-band, which arranges the pass-band and stop-band in parallel to allow signals in a specific frequency range to pass. However, due to the design of the parallel arrangement of the microstrip transmission lines of the existing comb-shaped bandpass filter, it has a large area and a large size. That is, the conventional comb-shaped bandpass filter has the disadvantage that it is difficult to miniaturize it.

On the other hand, as is well known by electronic engineers in the art, when the filter is displaced due to manufacturing errors, the length of the transmission line of the existing comb-shaped bandpass filter will be changed, thereby affecting the existing comb-shaped bandpass rate wave The noise suppression effect of the device and its production yield.

It can be seen from the above that there is still room for improvement in the existing resonant filter. In view of this, the inventor of the present invention has made great efforts to research and create, and finally developed a miniature bandpass filter of the present invention.

The miniature bandpass filter of the present invention includes: a first resonance unit, a second resonance unit, a third resonance unit and a fourth resonance unit. Wherein, the miniature bandpass filter of the present invention is implemented in a main body. It should be noted that the main body includes a resonant substrate, and a first ground layer is formed on the resonant substrate. And, the first ground layer includes a first connection portion connected to a first transmission layer. According to the design of the present invention, the top-view shape of the first connecting portion is H-shaped, so as to improve the effect of position offset on the insertion loss (IL)/return loss (RL) of the miniature bandpass filter in the operating frequency band. Influence. Furthermore, the top-view shapes of the first, second, third transmission lines and a fourth transmission line are L-shaped or U-shaped, thereby reducing the component size of the miniature bandpass filter.

In order to achieve the above-mentioned main purpose of the present invention, the inventor of this case provides an embodiment of the miniature bandpass filter, which includes: A first resonance unit, comprising: a first transmission line, one end of which is connected to an input end; and a first ground capacitor, one end of which is coupled to the other end of the first transmission line, and the other end of which is coupled to a ground unit; A second resonance unit, which includes a second transmission line and a second ground capacitor connected in series with the second transmission line, and is electrically connected to the ground unit: a third resonance unit, which includes a third transmission line and a third ground capacitor connected in series with the third transmission line, and is electrically connected to the ground unit: and a fourth resonance unit, comprising: a fourth transmission line, one end of which is connected to an output end; a fourth ground capacitor, one end of which is coupled to the other end of the fourth transmission line, and the other end of which is coupled to a ground unit; Wherein, the first resonance unit, the second resonance unit, the third resonance unit and the fourth resonance unit are implemented in a main body, and the input end and the output end are exposed outside the main body; Wherein, the main body is formed by stacking a plurality of dielectric plates, and the plurality of dielectric plates includes a resonant substrate; a first ground layer is formed on the resonant substrate, and a first ground layer of the first ground layer is formed. The top view shape of a connecting portion is H-shape.

In order to describe the miniature bandpass filter proposed by the present invention more clearly, the preferred embodiments of the present invention will be described in detail below with reference to the drawings.

first embodiment

1 shows a perspective perspective view of a first embodiment of a miniature bandpass filter of the present invention, and FIG. 2 shows a schematic diagram of a first embodiment of a miniature bandpass filter of the present invention. The miniature bandpass filter 1 of the present invention comprises: a first resonance unit TLC1', a second resonance unit TLC2', a third resonance unit TLC3' and a fourth resonance unit TLC4'. As shown in FIG. 2, the first resonance unit TLC1' includes a first transmission line TL1' and a first ground capacitor C1', and one end of the first transmission line TL1' is connected to an input end N'. Furthermore, one end of the first ground capacitor C1' is coupled to the other end of the first transmission line TL1', and the other end thereof is coupled to a ground unit. Next, the third resonance unit TLC3' includes a third transmission line TL3' and a third ground capacitor C3' connected in series with the third transmission line TL3', and is electrically connected to the ground unit. Similarly, the fourth resonance unit TLC4' includes a fourth transmission line TL4' and a fourth ground capacitor C4' connected in series with the fourth transmission line TL4', and is electrically connected to the ground unit.

As mentioned above, the second resonance unit TLC2' includes a second transmission line TL2' and a second ground capacitor C2'. In more detail, one end of the second transmission line TL2' is connected to an output end O'. Furthermore, one end of the second ground capacitor C2' is coupled to the other end of the second transmission line TL2', and the other end thereof is coupled to the ground unit. It is added that a first coupling schematic line M13, a second coupling schematic line M12, a third coupling schematic line M24 and a fourth coupling schematic line M34 in FIG. 2 are used to represent the resonance unit ( The electromagnetic coupling relationship between TLC1', TLC2', TLC3', TLC4'); for example, the first coupling schematic line M13 represents the connection between the first resonance unit TLC1' and the third resonance unit TLC3' The electromagnetic coupling relationship, and the second coupling schematic line M12 is the electromagnetic coupling relationship between the first resonance unit TLC1' and the second resonance unit TLC2'. It is easy to understand that the third coupling schematic line M24 represents the electromagnetic coupling relationship between the second resonance unit TLC2' and the fourth resonance unit TLC4', and the fourth coupling schematic line M34 is the third resonance unit The electromagnetic coupling relationship between the TLC3' and the fourth resonance unit TLC4'. In the present invention, the first resonance unit TLC1', the second resonance unit TLC2', the third resonance unit TLC3' and the fourth resonance unit TLC4' are implemented in a main body S, and the input terminal N' and the output terminal O' are formed on the surface of the main body S equivalently. It should be noted that the main body S is formed by stacking a plurality of dielectric plates, and the plurality of dielectric plates includes a resonant substrate S1 . According to the design of the present invention, a first ground layer G1 is formed on the resonant substrate S1 , and a first connection portion GC1 of the first ground layer G1 is H-shaped in plan view.

FIG. 3 shows an exploded view of the first embodiment of the miniature bandpass filter of the present invention. As shown in FIG. 3 , the plurality of dielectric plates include: a ground substrate S2 , a capacitor substrate S3 and an isolation substrate S4 . The ground substrate S2 is stacked under the resonant substrate S1, and the ground substrate S2 is formed with: an input layer N1, an output layer O1, a ground electrode layer GS1, and is located in the input layer N1 At least one input conductive column V1 in the output layer O1, at least one output conductive column V2 in the output layer O1, and a plurality of first conductive columns V3 in the ground electrode layer GS1. Next, the capacitor substrate S3 is stacked on the resonant substrate S1, and the capacitor substrate S3 is formed with: a first conductor layer C1, a second conductor layer C2, a third conductor layer C3, a first conductor layer C3, and a second conductor layer C2. Four conductor layers C4 and a plurality of second conductive pillars V4.

As mentioned above, the isolation substrate S4 is stacked on the capacitor substrate S3, and the isolation substrate S4 is formed with an isolation ground layer SG and a plurality of third conductive pillars V5. It should be noted that the resonant substrate S1 is further formed with: a second ground layer G2, a first transmission layer TL1 connected to the first ground layer G1, and a second transmission layer connected to the first ground layer G1 TL2, a third transmission layer TL3 connected to the second ground layer G2, a fourth transmission layer TL4 connected to the second ground layer G2, and a plurality of fourth conductive pillars V6. In the present invention, the first transmission layer TL1 equivalently forms the first transmission line TL1', and the second transmission layer TL2 equivalently forms the second transmission line TL2'. In addition, the third transmission layer TL3 equivalently forms the third transmission line TL3', and the fourth transmission layer TL4 equivalently forms the fourth transmission line TL4'. Wherein, the first, second, third and fourth transmission layers (TL1, TL2, TL3, TL4) are all transmission line segments with line lengths less than one quarter wavelength.

Based on the above, the first conductor layer C1 equivalently forms the first capacitor, and the second conductor layer C2 equivalently forms the second capacitor. Similarly, the third conductor layer C3 equivalently forms the third capacitor, and the fourth conductor layer C4 equivalently forms the fourth capacitor. It should be noted that the first ground layer G1 includes a first connection portion GC1 connected to the first transmission layer TL1 and a second connection portion GC2 connected to the second transmission layer TL2. Moreover, the second ground layer G2 includes a third connection portion GC3 connected to the third transmission layer TL3, and a fourth connection portion GC4 connected to the fourth transmission layer TL4. In this embodiment, the first connection portion GC1 , the second connection portion GC2 , the third connection portion GC3 , and the fourth connection portion GC4 are H-shaped in plan view. It is conceivable that the top view shape of the first connection part GC1, the second connection part GC2, the third connection part GC3 and the fourth connection part GC4 can be any one of the following: H shape , rectangle, I shape. Furthermore, the first conductor layer C1 and the first transfer layer TL1 are equivalent to form the first ground capacitor C1 ′, and the second conductor layer C2 and the second transfer layer TL2 are equivalent to form the second ground capacitor C2 '. The third conductor layer C3 and the third transfer layer TL3 are equivalent to form the third ground capacitor C3', and the fourth conductor layer C4 and the fourth transfer layer TL4 are equivalent to form the fourth ground capacitor C4'.

Continue to refer to FIGS. 1-3 . The corresponding plurality of first conductive columns V3 and the corresponding plurality of second conductive columns V4 communicate with the corresponding plurality of third conductive columns V5. In addition, the ground electrode layer G1, the isolation ground layer SG, the first ground layer G1 and the second ground layer G2 are connected in series to form the ground unit. It is added that each of the dielectric plates is a ceramic substrate.

Second Embodiment

FIG. 4 shows a perspective perspective view of the second embodiment of the miniature bandpass filter of the present invention, and FIG. 5 shows an exploded view of the second embodiment of the miniature bandpass filter of the present invention. It can be seen from FIG. 3 and FIG. 5 that, compared with the aforementioned first embodiment, the third connecting portion GC3 is connected to the fourth connecting portion GC4 and its top view shape is I-shape.

According to the design of the H-shaped connecting parts (GC1, GC2, GC3, GC4) of the present invention, the miniature bandpass filter of the present invention can effectively improve the influence caused by the position offset. FIG. 6 shows a first frequency response comparison diagram of the miniature bandpass filter of the present invention and a conventional filter. FIG. 7 shows a second frequency response comparison diagram of the miniature bandpass filter of the present invention and the conventional filter. To be more specific, FIG. 6 and FIG. 7 are comparison diagrams of frequency responses of the resonant substrate with a positive displacement of 1.5 mil in the X-axis alignment of the resonant substrate. Also, as shown in FIG. 8 , the thin black line is the frequency response without offset, the thick black line is the frequency response of the miniature bandpass filter of the present invention, and the thin dashed line is the frequency response of the conventional filter. As is well known to engineers in the art, a frequency response graph shows the relative relationship between return loss and insertion loss measured at the input and output ends of a resonant filter at the operating frequency.

It is added that the line length of the transmission layer (TL1, TL2, TL3, TL4) is less than a quarter of the wavelength, and its shape can be U-shaped or L-shaped. With such design, the miniature bandpass filter of the present invention has a smaller size. Furthermore, the user can adjust the micro-bandpass filter by adjusting the line length of the transmission layer (TL1, TL2, TL3, TL4) and the size of the conductor layer (C1, C2, C3, C4). the resonant frequency of the device. In addition, by adjusting the distance between the transmission layers (TL1, TL2, TL3, TL4), the bandwidth and attenuation of the micro-bandpass filter are further adjusted.

Based on the above, please refer to FIG. 8 and FIG. 9 at the same time. FIG. 8 shows a third frequency response comparison diagram of the miniature bandpass filter of the present invention and the conventional filter. FIG. 9 shows a fourth frequency response comparison diagram of the miniature bandpass filter of the present invention and a conventional filter. To be more specific, FIG. 8 and FIG. 9 are comparison diagrams of the frequency responses of the resonant substrate with a negative offset of 1.5 mil in the S1X axis alignment. It can be known from FIG. 6 to FIG. 9 that the miniature bandpass filter with H-shaped connection parts (GC1, GC2, GC3, GC4) of the present invention is compared with the conventional filter without H-shaped connection part. The miniature bandpass filter of the present invention has high stability of insertion loss (IL)/return loss (RL) within the operating frequency band (27.5-29.5GHz). That is to say, the miniature bandpass filter of the present invention has the advantages of improving the effect of the offset and high stability.

In this way, the above has completely and clearly explained the technical features and perspective views of the miniature bandpass filter of the present invention. Through the above, we can know that the present invention has the following advantages:

(1) The miniature bandpass filter 1 of the present invention comprises: a first resonance unit TLC1', a second resonance unit TLC2', a third resonance unit TLC3' and a fourth resonance unit TLC4'. The first resonance unit TLC1' includes a first transmission line TL1' and a first ground capacitor C1', and one end of the first transmission line TL1' is connected to an input end N1. One end of the first ground capacitor C1' is coupled to the other end of the first transmission line TL1', and the other end thereof is coupled to a ground unit. Next, the second resonance unit TLC2' includes a second transmission line TL2' and a second ground capacitor C2' connected in series with the second transmission line TL2', and is electrically connected to the ground unit. Similarly, the third resonance unit TLC3' includes a third transmission line TL3' and a third ground capacitor C3' connected in series with the third transmission line TL3', and is electrically connected to the ground unit. And, the fourth resonance unit TTLC4' includes a fourth transmission line TL4' and a fourth ground capacitor C4' connected in series with the fourth transmission line TL4', and is electrically connected to the ground unit. It should be noted that the main body S includes a resonant substrate S1, and the resonant substrate S1 is formed with a first ground layer G1. Moreover, the first ground layer G1 includes a first connection portion GC1 connected to a first transmission layer C1. According to the design of the present invention, the top view shape of the first connecting portion GC1 is H-shape, so as to improve the insertion loss (IL)/ The effect of return loss (RL). Furthermore, the top-view shapes of the first transmission line TL1' and a second transmission line TL2' are L-shape or U-shape, so as to reduce the component size of the miniature bandpass filter. In this way, the miniature bandpass filter of the present invention has the advantages of improving the effect of the bit offset, high stability and miniaturized size.

It must be emphasized that the above-mentioned detailed descriptions are for specific descriptions of feasible embodiments of the present invention, but the embodiments are not intended to limit the patent scope of the present invention. All should be included in the scope of the patent in this case.

<The present invention>

1: Miniature bandpass filter

TLC1': the first resonance unit

TLC2': Second resonance unit

TLC3': The third resonance unit

TLC4': Fourth resonance unit

TL1': The first transmission line

TL2': second transmission line

TL3': The third transmission line

TL4': Fourth transmission line

C1': first ground capacitor

C2': Second ground capacitor

C3': the third ground capacitor

C4': Fourth ground capacitor

N': input terminal

O': output terminal

S: main body

S1: Resonant substrate

G1: first ground plane

G2: Second ground plane

TL1: The first transport layer

TL2: Second Transport Layer

TL3: The third transport layer

TL4: Fourth transport layer

GC1: first connection part

GC2: Second connector

GC3: Third link

GC4: Fourth link

S2: Ground Substrate

N1: Input layer

O1: output layer

GS1: Ground electrode layer

V1: Input conductive column

V2: output conductive column

V3: The first conductive column

V4: The second conductive column

V5: The third conductive column

V6: Fourth conductive pillar

S3: Capacitor Substrate

C1: The first conductor layer

C2: Second Conductor Layer

C3: The third conductor layer

C4: Fourth conductor layer

S4: Isolation Substrate

SG: Isolated Ground Plane

M12: Second coupling schematic line

M13: The first coupling schematic line

M24: The third coupling schematic line

M34: Fourth coupling schematic line

＜Knowledge＞

none.

FIG. 1 shows a perspective perspective view of a first embodiment of a miniature bandpass filter of the present invention; FIG. 2 shows a schematic diagram of the first embodiment of the miniature bandpass filter of the present invention; FIG. 3 shows an exploded view of the first embodiment of the miniature bandpass filter of the present invention; 4 is a perspective view showing a second embodiment of the miniature bandpass filter of the present invention; Figure 5 shows an exploded view of a second embodiment of the miniature bandpass filter of the present invention; 6 shows a first frequency response comparison diagram of the miniature bandpass filter of the present invention and a conventional filter; 7 shows a second frequency response comparison diagram of the miniature bandpass filter of the present invention and a conventional filter; FIG. 8 shows a third frequency response comparison diagram of the miniature bandpass filter of the present invention and a conventional filter; and FIG. 9 shows a fourth frequency response comparison diagram of the miniature bandpass filter of the present invention and a conventional filter.

1: Miniature bandpass filter

S: main body

TL1: The first transport layer

TL2: Second Transport Layer

TL3: The third transport layer

TL4: Fourth transport layer

GC1: first connection part

GC2: Second connector

GC3: Third link

GC4: Fourth link

N1: Input layer

C1: The first conductor layer

C2: Second Conductor Layer

C3: The third conductor layer

C4: Fourth conductor layer

Claims (9)

A miniature bandpass filter, comprising: a first resonance unit, including: a first transmission line, one end of which is coupled to an input end; and a first ground capacitor, one end of which is coupled to the other end of the first transmission line, and its other end is connected to a grounding unit; a second resonance unit, which includes a second transmission line and a second grounding capacitor connected in series with the second transmission line, and is electrically connected to the grounding unit: a third resonance unit , which includes a third transmission line and a third ground capacitor connected in series with the third transmission line, and is electrically connected to the ground unit; and a fourth resonance unit, including: a fourth transmission line, one end of which is coupled to an output a fourth grounding capacitor, one end of which is coupled to the other end of the fourth transmission line, and the other end of which is connected to the grounding unit; wherein the first resonance unit, the second resonance unit, the third resonance unit and The fourth harmonic unit is realized in a main body, and the input end and the output end are located on the surface of the main body; wherein, the main body system is formed by superimposing a plurality of dielectric plates, and the plurality of The dielectric plate system includes a resonant substrate; a first ground layer is formed on the resonant substrate, and a first connection portion of the first ground layer is H-shaped in plan view. The miniature bandpass filter of claim 1, wherein a first input signal of the first transmission line is coupled to the second transmission line and the third transmission line. The miniature bandpass filter of claim 1, wherein the plurality of dielectric plates comprises: a ground substrate, which is stacked under the resonant substrate, and the ground substrate is formed with: an input layer and an output layer , a ground electrode layer, at least one input conductive column located in the input layer, at least one output conductive column located in the output layer, and a plurality of first conductive columns located in the ground electrode layer; a capacitor substrate, which is It is stacked above the resonant substrate, and the capacitor substrate is formed with: a first conductor layer, a second conductor layer, a third conductor layer, a fourth conductor layer and a plurality of second conductive pillars; an isolation The substrate is stacked above the capacitor substrate, and the isolation substrate is formed with: an isolation ground layer and a plurality of third conductive pillars; wherein, the resonant substrate is further formed with: a second ground layer connected to the A first transmission layer of the first ground layer, a plurality of fourth conductive pillars, a second transmission layer connected to the first ground layer, a third transmission layer connected to the second ground layer, and a second transmission layer connected to the second ground layer A fourth transmission layer of the ground layer; wherein, the first transmission layer equivalently forms the first transmission line, and the second transmission layer equivalently forms the second transmission line; wherein, the third transmission layer equivalently forms the first transmission line Three transmission lines, and the fourth transmission layer equivalently forms the fourth transmission line; wherein, the first conductor layer and the first transmission layer are equivalent to form the first ground capacitor, and the second conductor layer and the second transmission layer are equivalent to forming the first ground capacitor The second ground capacitor is formed by the equivalent layer; wherein, the third conductor layer is equivalent to the third transmission layer to form the third ground capacitor, and the fourth conductor layer is equivalent to the fourth transmission layer to form the fourth ground capacitance; Wherein, the first ground layer includes a second connection part connected with the second transmission layer; wherein, the second ground layer includes a third connection part connected with the third transmission layer, and A fourth connecting portion connected to the fourth transport layer. The miniature bandpass filter of claim 3, wherein the top-view shape of the second connection portion can be any one of the following: H shape, rectangle, and I shape. The miniature bandpass filter of claim 3, wherein the top-view shape of the third connection portion and the fourth connection portion can be any one of the following: H-shape, rectangle, and I-shape. The miniature bandpass filter of claim 3, wherein the third connecting portion is connected to the fourth connecting portion and its plan view shape is I-shape. The miniature bandpass filter of claim 3, wherein the corresponding plurality of first conductive columns, the corresponding plurality of second conductive columns and the corresponding plurality of third conductive columns communicate with each other. The miniature bandpass filter of claim 3, wherein the ground electrode layer, the isolation ground layer, the first ground layer and the second ground layer are connected in series to form the ground unit. The miniature bandpass filter of claim 3, wherein each of the dielectric plates is a ceramic substrate.

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