TW202230969A - Filter device - Google Patents

Abstract

The invention discloses a filter device comprising a substrate, at least one transmission line, and a first reference conductor. The transmission line is disposed on a first surface of the substrate. The first reference conductor is disposed on a second surface of the substrate, and includes a slotted structure. The slotted structure comprises a frame body part, a slotted-shaped part, and a hollow part. The slotted-shaped part surrounds the frame body part, and the hollow part is formed in the frame body part. At least one first impedance unit is configured to connect the frame body part, or connected between the frame body part and the first reference conductor.

Description

filter

The present invention relates to a filter and its equivalent filter circuit, in particular to a filter that can absorb electromagnetic noise and its equivalent filter circuit.

In today's electronic products, the requirements for the data transmission rate are rising rapidly, which makes the signal transmission speed of high-speed digital transmission interfaces (such as USB, HDMI, Thunderbolt) faster and faster. However, when signals pass through discontinuous structures, such as through-layer vias, zigzag wiring or connector interfaces, it is very easy to generate noise and cause electromagnetic interference (EMI) or radio frequency interference (RFI) problems. When EMI or RFI occurs, the operation of the internal components of electronic products will be affected.

Traditional filters are all reflective filters. The reflective filter will reflect the noise back to the original path, such as the previous circuit, to prevent the noise from interfering with the circuit to be protected. However, the reflected noise will still remain in the circuit, making the problem of electromagnetic interference still exist.

An objective of the present invention is to provide a filter, which includes a substrate, at least one transmission line and a first reference conductor. The transmission line is arranged on a first surface of the substrate, and the first reference conductor is arranged on a second surface of the substrate. The first reference conductor includes a slot-like structure. The trough-shaped structure includes a frame body, a trough-shaped part and a hollow part. The groove portion surrounds the frame portion, and the hollow portion is formed in the frame portion. One or more impedance units are arranged on the frame body part and/or the slot-shaped part, and the filter uses the impedance units to absorb noise of a specific frequency.

Another object of the present invention is to provide a filter, wherein the slot-like structure of the filter is provided with a second reference conductor in the hollow portion, and the second reference conductor is located at a corresponding position of the transmission line. With the arrangement of the second reference conductor, the capacitive coupling effect between the transmission line and the slot-like structure is increased, so that the signal passing through the filter can achieve better impedance matching and achieve better signal quality.

The present invention provides a filter, comprising: a substrate; at least one transmission line disposed on a first surface of the substrate; and a first reference conductor disposed on a second surface of the substrate and including a slot-like structure inside , the trough-shaped structure includes: a frame body part; a groove-shaped part surrounding the frame body part; and a hollow part formed in the frame body part; wherein, at least one first impedance unit is connected to the frame body part.

In an embodiment of the present invention, the frame portion is a quadrilateral frame and includes a first side, a second side, a third side and a fourth side, the first side corresponds to the third side, and the second side Corresponding to the fourth side, the transmission line is projected across the first side and the third side of the frame portion.

In an embodiment of the present invention, at least one second impedance unit is further included. The first impedance unit is disposed on the first side of the frame body corresponding to the position of the transmission line, and the second impedance unit is disposed corresponding to the position of the transmission line. on the third side of the frame body.

In an embodiment of the present invention, at least one third impedance unit is further included, and the third impedance unit is disposed on the second side or the fourth side of the frame body.

In an embodiment of the present invention, at least one third impedance unit is further included, and the third impedance unit is disposed on the second side or the fourth side of the frame body.

In an embodiment of the present invention, at least one fourth impedance unit is further included, the fourth impedance unit is disposed in the groove portion, and the left end or the right end of the first impedance unit is connected to the first reference conductor through the fourth impedance unit.

In an embodiment of the present invention, it further includes at least one fourth impedance unit and at least one fifth impedance unit, the fourth impedance unit and the fifth impedance unit are disposed in the groove portion, and the left end or the right end of the first impedance unit passes through the fourth impedance unit. The impedance unit is connected to the first reference conductor, and the left end or the right end of the second impedance unit is connected to the first reference conductor through the fifth impedance unit.

In an embodiment of the present invention, it further includes at least one fourth impedance unit and at least one sixth impedance unit, the fourth impedance unit and the sixth impedance unit are respectively disposed in the groove portion, and the left end or the right end of the first impedance unit passes through the first impedance unit. The four impedance units are connected to the first reference conductor, and the left end or the right end of the third impedance unit is connected to the first reference conductor through the sixth impedance unit.

In an embodiment of the present invention, it further includes at least one fourth impedance unit, at least one fifth impedance unit and at least one sixth impedance unit, and the fourth impedance unit, the fifth impedance unit and the sixth impedance unit are respectively disposed in the slot-shaped portion The left or right end of the first impedance unit is connected to the first reference conductor through the fourth impedance unit, the left or right end of the second impedance unit is connected to the first reference conductor through the fifth impedance unit, and the left or right end of the third impedance unit is connected to the first reference conductor through the fifth impedance unit. The six-impedance unit is connected to the first reference conductor.

In an embodiment of the present invention, at least one fourth impedance unit is further included, the fourth impedance unit is disposed in the slot-shaped portion, one end of each fourth impedance unit is connected between two adjacent first impedance units and the other end is connected Connect the first reference conductor.

In an embodiment of the present invention, it further includes at least one fourth impedance unit and at least one fifth impedance unit, the fourth impedance unit and the fifth impedance unit are disposed in the groove portion, and one end of each fourth impedance unit is connected to two One end of each of the fifth impedance units is connected between two adjacent second impedance units and the other end is connected to the first reference conductor.

In an embodiment of the present invention, it further includes at least one fourth impedance unit and at least one sixth impedance unit, the fourth impedance unit and the sixth impedance unit are respectively disposed in the groove portion, and one end of each fourth impedance unit is connected to the The other end of the two adjacent first impedance units is connected to the first reference conductor, one end of each sixth impedance unit is connected between the two adjacent third impedance units and the other end is connected to the first reference conductor.

In an embodiment of the present invention, it further includes at least one fourth impedance unit, at least one fifth impedance unit and at least one sixth impedance unit, and the fourth impedance unit, the fifth impedance unit and the sixth impedance unit are respectively disposed in the slot-shaped portion One end of each fourth impedance unit is connected between two adjacent first impedance units and the other end is connected to the first reference conductor, and one end of each fifth impedance unit is connected to two adjacent second impedance units The other end is connected to the first reference conductor, one end of each sixth impedance unit is connected between two adjacent third impedance units and the other end is connected to the first reference conductor.

In an embodiment of the present invention, the slot-like structure further includes a second reference conductor, and the second reference conductor is disposed in the hollow portion corresponding to the position of the transmission line.

In an embodiment of the present invention, the number of transmission lines is two to form a pair of differential transmission lines.

In an embodiment of the present invention, the frame portion and the first reference conductor form an asymmetric coplanar stripline.

The present invention further provides a filter, comprising: a substrate; at least one transmission line disposed on a first surface of the substrate; and a first reference conductor disposed on a second surface of the substrate and including a slot-shaped structure, the groove-shaped structure includes: a frame body part; a groove-shaped part surrounding the periphery of the frame body part; and a hollow part formed in the frame body part; wherein, at least one first impedance unit is arranged in the groove-shaped part The part is connected to the frame body part and the first reference conductor.

In an embodiment of the present invention, at least one second impedance unit is further included. The first impedance unit is disposed in the slot-shaped portion corresponding to the position of the transmission line and is used to connect the first side of the frame portion and the first reference conductor, The second impedance unit is disposed in the slot portion corresponding to the position of the transmission line and is used for connecting the third side of the frame portion and the first reference conductor.

In an embodiment of the present invention, at least one third impedance unit is further included. The third impedance unit is disposed in the groove portion and is used for connecting the second side of the frame portion and the first reference conductor or for connecting the frame portion. the fourth side and the first reference conductor.

In an embodiment of the present invention, at least one third impedance unit is further included. The first impedance unit is disposed in the slot-shaped portion corresponding to the position of the transmission line and used to connect the first side of the frame portion and the first reference conductor, The third impedance unit is disposed in the slot portion and is used for connecting the second side of the frame portion and the first reference conductor or for connecting the fourth side of the frame portion and the first reference conductor.

Please refer to FIG. 1 , which is a circuit diagram of an equivalent filter circuit according to an embodiment of the present invention. As shown in FIG. 1 , the equivalent filter circuit 200 is used to suppress electromagnetic noise of a specific frequency, and is a single-ended equivalent filter circuit. The equivalent filter circuit 200 includes at least one first equivalent transmission line model 21 and at least one second equivalent transmission line model 22 . The first equivalent transmission line model 21 includes a first main transmission line 211 and a first auxiliary transmission line 212 . The second equivalent transmission line model 22 includes a second main transmission line 221 and a second secondary transmission line 222 .

The left end of the first main transmission line 211 is connected to a signal input port 2111 , and the right end is connected to a signal output port 2112 . The left and right ends of the second main transmission line 221 are respectively connected to a reference potential (V). The left end of the first sub-transmission line 212 is connected to the left end of the second sub-transmission line 222 , and the right end of the first sub-transmission line 212 is connected to the right end of the second sub-transmission line 222 .

The equivalent filter circuit 200 of the present invention is an absorption-type equivalent filter circuit, and at least one impedance unit can be set in the circuit to absorb the noise of at least one specific frequency by using the impedance unit. In this embodiment, at least one first impedance unit 31 is connected in series between the left end of the first sub-transmission line 212 and the left end of the second sub-transmission line 222 . Alternatively, at least one second impedance unit 32 is connected in series between the right end of the first sub-transmission line 212 and the right end of the second sub-transmission line 222 .

Furthermore, further, two single-ended equivalent filter circuits 200 can be combined into a differential equivalent filter circuit. As shown in FIG. 2 , the differential equivalent filter circuit includes two first equivalent transmission line models 21 and two second equivalent transmission line models 22 . The left ends of the second sub-transmission lines 222 of each second equivalent transmission line model 22 are connected together through the first impedance unit 31 respectively, and the right ends are connected together directly or through the second impedance unit 32 respectively.

Please refer to FIG. 3 , which is a circuit diagram of another embodiment of an equivalent filter circuit of the present invention. The equivalent filter circuit 201 in this embodiment further includes at least one third equivalent transmission line model 23 . The third equivalent transmission line model 23 includes a third main transmission line 231 and a third auxiliary transmission line 232 . The left end of the second main transmission line 221 is connected to the reference potential through the third main transmission line 231 , and the third sub transmission line 232 and the first impedance unit 31 are connected in series between the left end of the first sub transmission line 212 and the left end of the second sub transmission line 222 .

Please refer to FIG. 4 , which is a circuit diagram of another embodiment of the equivalent filter circuit of the present invention. Compared with the equivalent filter circuit 201 of the embodiment of FIG. 3 , the equivalent filter circuit 202 of the present embodiment further includes at least one second impedance unit 32 and at least one third impedance unit 33 . The second impedance unit 32 is connected in series between the right end of the first sub-transmission line 212 and the right end of the second sub-transmission line 222 , and the third impedance unit 33 is connected in series between the left end of the first sub-transmission line 212 and the left end of the third sub-transmission line 232 .

Furthermore, further, two single-ended equivalent filter circuits 201/202 can be combined into a differential equivalent filter circuit. As shown in FIG. 5 , the differential equivalent filter circuit includes two first equivalent transmission line models 21 , two second equivalent transmission line models 22 and two third equivalent transmission line models 23 . In an embodiment of the present invention, the left ends of the third sub-transmission lines 232 of each third equivalent transmission line model 23 are directly connected together or connected together through the third impedance unit 33 , and the third sub-transmission line 232 of each second equivalent transmission line model 22 The right ends of the two secondary transmission lines 222 are directly connected together or connected together through the second impedance unit 32 .

Please refer to FIG. 6 , which is a circuit diagram of another embodiment of an equivalent filter circuit of the present invention. Compared with the equivalent filter circuit 201 of the embodiment of FIG. 3 , the equivalent filter circuit 203 of the present embodiment further includes at least one fourth impedance unit 34 . The fourth impedance unit 34 is connected in series between the right end of the first impedance unit 31 and the second main transmission line 221 . Alternatively, the fourth impedance unit 34 is connected in series between the left end of the first impedance unit 31 and the second main transmission line 221 .

Please refer to FIG. 7 , which is a circuit diagram of another embodiment of an equivalent filter circuit of the present invention. Compared with the equivalent filter circuit 203 of the embodiment of FIG. 6 , the equivalent filter circuit 204 of this embodiment further includes at least one second impedance unit 32 , at least one third impedance unit 33 , at least one fifth impedance unit 35 and at least one The sixth impedance unit 36 .

The second impedance unit 32 is connected in series between the right end of the first sub-transmission line 212 and the right end of the second sub-transmission line 222 , and the third impedance unit 33 is connected in series between the left end of the first sub-transmission line 212 and the left end of the third sub-transmission line 232 . At least one fifth impedance unit 35 is connected in series between the right end of the second impedance unit 32 and the reference potential, or at least one fifth impedance unit 35 is connected in series between the left end of the second impedance unit 32 and the reference potential. At least one sixth impedance unit 36 is connected in series between the right end of the third impedance unit 33 and the reference potential, or at least one sixth impedance unit 36 is connected in series between the left end of the third impedance unit 33 and the reference potential. In this embodiment, the fourth impedance units 34 on the left and right sides of the first impedance unit 31 may have the same impedance value or different impedance values, and the fifth impedance units 35 on the left and right sides of the second impedance unit 32 may have the same impedance value Impedance values or different impedance values, while the sixth impedance units 36 on the left and right of the third impedance unit 33 may have the same impedance value or different impedance values.

Please refer to FIG. 8 , which is a circuit diagram of another embodiment of an equivalent filter circuit of the present invention. Two or more first impedance units 31 are connected in series between the second sub-transmission line 222 and the third sub-transmission line 232 of the equivalent filter circuit 205 in this embodiment. In addition, the equivalent filter circuit 205 in this embodiment further includes at least one fourth impedance unit 34 . One end of each fourth impedance unit 34 is connected between two adjacent first impedance units 31 and the other end is connected to the second main transmission line 221 .

Please refer to FIG. 9 , which is a circuit diagram of another embodiment of an equivalent filter circuit of the present invention. Compared with the equivalent filter circuit 205 of the embodiment of FIG. 8 , the equivalent filter circuit 206 of this embodiment further includes two or more second impedance units 32 , two or more third impedance units 33 , and at least one fifth impedance unit 35 and at least one sixth impedance unit 36 .

More than two second impedance units 32 are connected in series between the right end of the first sub-transmission line 212 and the right end of the second sub-transmission line 222 , and two or more third impedance units 33 are connected in series between the left end of the first sub-transmission line 212 and the right end of the second sub-transmission line 222 . Between the left ends of the third sub-transmission line 232 . One end of each fifth impedance unit 35 is connected between two adjacent second impedance units 32 and the other end is connected to a reference potential, and one end of each sixth impedance unit 36 is connected between two adjacent third impedance units 33 and the other end is connected to the reference potential. In this embodiment, the first impedance units 31 on the left and right sides of the fourth impedance unit 34 may have the same impedance value or different impedance values, and the second impedance units 32 on the left and right sides of the fifth impedance unit 35 may have the same impedance value The third impedance units 33 on the left and right of the sixth impedance unit 36 may have the same impedance value or different impedance values.

Please refer to FIG. 10 , which is a circuit diagram of another embodiment of the equivalent filter circuit of the present invention. Compared with the equivalent filter circuit 200 of the embodiment of FIG. 1 that sets the impedance units in series, the equivalent filter circuit 207 of the present embodiment sets at least one impedance unit in a parallel manner. For example, the second equivalent transmission line model 22 transmits through The left end of the second main transmission line 221 and the left end of the second auxiliary transmission line 222 are connected in parallel with at least one impedance unit 31 , or the second equivalent transmission line model 22 is connected in parallel with at least one impedance unit 31 through the right end of the second main transmission line 221 and the right end of the second auxiliary transmission line 222 Two impedance units 32 .

Please refer to FIG. 11 , which is a circuit diagram of another embodiment of the equivalent filter circuit of the present invention. Compared with the equivalent filter circuit 207 of the embodiment of FIG. 10 , the equivalent filter circuit 208 of this embodiment further includes a third equivalent transmission line model 23 . The third equivalent transmission line model 23 connects at least one first impedance unit 31 in parallel through the right end of the third main transmission line 231 and the right end of the third auxiliary transmission line 232 , and connects in parallel through the left end of the third main transmission line 231 and the left end of the third auxiliary transmission line 232 At least one third impedance unit 33 .

In the above embodiments, the first main transmission line 211 and the first auxiliary transmission line 212 of the first equivalent transmission line model 21 are coupled to generate a first characteristic impedance (Z1) and a first electrical length (θ1), and the second equivalent The second main transmission line 221 and the second auxiliary transmission line 222 of the transmission line model 22 are coupled to generate a second characteristic impedance (Z2) and a second electrical length (θ2), and the third main transmission line 231 of the third equivalent transmission line model 23 Coupling with the third sub-transmission line 232 generates a third characteristic impedance ( Z3 ) and a third electrical length ( θ3 ). In the present invention, each characteristic impedance ( Z1 , Z2 , Z3 ) can be designed to have the same or different impedance values, and each electrical length ( θ1 , θ2 , θ3 ) can also be designed to have the same or different electrical length. In an embodiment of the present invention, the second electrical length ( θ2 ) and the third electrical length ( θ3 ) approach zero.

A transmission line structure formed by the first equivalent transmission line model 21 , the second equivalent transmission line model 22 or the third equivalent transmission line model 23 may be a microstrip line, a slot line, An artificial transmission line, a modified-T circuit line, or other transmission line structures that can be used to transmit signals.

Continuing from the above, the equivalent filter circuit 200/201/202/203/204/205/206/207/208 of the present invention is configured with one or more impedance units 31, 32, 33, 34, 35 or 36, so as to achieve the purpose of absorbing electromagnetic noise of a specific frequency through the impedance unit 31, 32, 33, 34, 35 or 36, thereby avoiding the reflection of the electromagnetic noise and affecting the quality of signal transmission. In the present invention, the impedance unit 31 , 32 , 33 , 34 , 35 or 36 can be at least one resistor, at least one inductor, at least one capacitor or a series-parallel combination of resistors, inductors and capacitors. In an embodiment of the present invention, the impedance units 31 , 32 , 33 , 34 , 35 and 36 can also be designed to have the same impedance value or different impedance values. In yet another embodiment of the present invention, the impedance value of one or more impedance units 31 , 32 , 33 , 34 , 35 , and 36 may be designed to be zero.

Please refer to FIG. 12 , FIG. 13 and FIG. 14 , which are respectively a three-dimensional perspective view, a top view and a bottom view of the structure of a filter according to an embodiment of the present invention, and also refer to FIG. 1 . As shown in FIGS. 12 , 13 and 14 , the filter 500 includes a substrate 51 , at least one transmission line 53 and a first reference conductor 55 . The transmission line 53 is arranged on a first surface (eg, the upper surface) of the substrate 51 , and the first reference conductor 55 is arranged on a second surface (eg, the lower surface) of the substrate 51 . The first reference conductor 55 includes a slot-like structure 57 . The slot-shaped structure 57 includes a frame portion 571 , a slot-shaped portion 573 and a hollow portion 575 . In the present invention, the transmission line 53, the frame portion 571 and the first reference conductor 55 may be microstrip lines, slot lines, artificial transmission lines, modified T circuit lines (modified T circuit lines) -T circuit line) or other transmission line structures that can be used to transmit signals. The groove portion 573 surrounds the frame portion 571 , and the hollow portion 575 is formed in the frame portion 571 . In addition, at least one first impedance unit 31 and/or at least one second impedance unit 32 are disposed on and connected to the frame body portion 571 . The frame portion 571 is a quadrilateral frame and includes a first side 5711 , a second side 5712 , a third side 5713 and a fourth side 5714 . One end of the first side 5711 is connected to one end of the third side 5713 through the second side 5712 , and the other end of the first side 5711 is connected to the other end of the third side 5713 through the fourth side 5714 . The first side 5711 corresponds to the third side 5713 and the second side 5712 corresponds to the fourth side 5714. The transmission line 53 is projected across the first side 5711 and the third side 5713 of the frame portion 571 . In this embodiment, the first impedance unit 31 is disposed on the first side 5711 of the frame body 571 corresponding to the position of the transmission line 53 . For example, the first impedance unit 31 is disposed on the frame body part at the lower left side of the transmission line 53 On the first side 5711 of the 571, the second impedance unit 32 is arranged on the third side 5713 of the frame body 571 corresponding to the position of the transmission line 53. on the third side 5713 of the frame portion 571 .

In an embodiment of the present invention, the first impedance unit 31 or the second impedance unit 32 is disposed on the frame body portion 571 and is directly connected to the frame body portion 571 . As shown in FIG. 14A , the frame portion 571 includes at least one notch 5710 . The first impedance unit 31 or the second impedance unit 32 is disposed on the notch 5710 of the frame portion 571 . The two ends are respectively directly connected to the frame parts 571 on both sides of the notch 5710 .

In yet another embodiment of the present invention, the first impedance unit 31 or the second impedance unit 32 is disposed on the frame body portion 571 and connected to the frame body portion 571 through conductive through holes. As shown in FIG. 14B , the substrate 51 is disposed above the first reference conductor 55 , and another substrate 59 is disposed below. The frame portion 571 includes at least one notch 5710 . Two conductive through holes 591 are provided in the substrate 59 , and both ends of the first impedance unit 31 or the second impedance unit 32 are respectively connected to the frame parts 571 on both sides of the gap 5710 through the corresponding conductive through holes 591 .

Next, referring to FIG. 1 , the equivalent filter circuit 200 of FIG. 1 can be equivalently formed by the filter 500 . The transmission line 53 is coupled with the frame body 571 to generate the first equivalent transmission line model 21 . The frame portion 571 is coupled with the first reference conductor 55 to generate the second equivalent transmission line model 22 . The first main transmission line 211 of the first equivalent transmission line model 21 represents the equivalent element of the transmission line 53 , and the first sub-transmission line 212 represents the equivalent element of the frame body 571 . The second main transmission line 221 of the second equivalent transmission line model 22 represents the equivalent element of the first reference conductor 55 , and the second secondary transmission line 222 represents the equivalent element of the frame body 571 . Furthermore, the first impedance unit 31 and the second impedance unit 32 of the filter 500 are equivalent to the first impedance unit 31 and the second impedance unit 32 in the equivalent filter circuit 200 in FIG. 1 .

In an embodiment of the present invention, the characteristic impedance (Z1, Z2) and electrical lengths (θ1, θ2). Then, the frequency at which the equivalent filter circuit 200 absorbs electromagnetic noise is adjusted by correcting the characteristic impedances ( Z1 , Z2 ) and/or the electrical lengths ( θ1 , θ2 ).

14 and 15 at the same time, in order to achieve the purpose of high impedance of the transmission line, the filter 500 of the present invention is provided with a frame portion 571 with a thinner width in the slot-like structure 57. The frame portion 571 with a thinner width is An Asymmetric Coplanar Strip is formed with the wider first reference conductor 55 . In the present invention, the frame portion 571 is disposed close to the first reference conductor 55, which can shorten the width (W) of the groove portion 573, so that the overall area of the filter 500 can be effectively reduced, and the circuit structure can be reduced. purpose of transformation. In addition, even if the frame portion 571 is disposed very close to the first reference conductor 55, there is still a large amount of electric field coupling between the frame portion 571 and the first reference conductor 55; however, since the present invention designs the frame portion 571 as a If the width is thinner, the inductance will increase, so that the inductance value will increase and the impedance of the transmission line (Z0) will increase accordingly, thereby achieving the purpose of high impedance of the transmission line.

Please refer to FIG. 16 which is a bottom view of the structure of the filter according to another embodiment of the present invention, and refer to FIG. 4 , FIG. 12 and FIG. 13 at the same time. Compared with the filter 500 of the embodiment of FIG. 14 , the filter 501 of the embodiment of FIG. 16 further includes at least one third impedance unit 33 . The third impedance unit 33 is selectively disposed on the second side 5712 or the fourth side 5714 of the frame portion 571 and connected to the frame portion 571 . The third impedance unit 33 in this embodiment may be disposed on the frame body portion 571 and directly connected to the frame body portion 571 in the manner of FIG. 14A ; alternatively, the third impedance unit 33 in this embodiment may also be disposed in the frame body portion 571 in the manner of FIG. The body portion 571 is connected to the frame body portion 571 through conductive through holes. The equivalent filter circuit 202 in FIG. 4 can be equivalently formed by the filter 501 . The transmission line 53 is coupled with the frame body 571 to generate the first equivalent transmission line model 21 . The frame portion 571 distributed on the right side of the third impedance unit 33 is coupled with the first reference conductor 55 to generate the second equivalent transmission line model 22 , and the frame portion 571 distributed on the left side of the third impedance unit 33 is coupled with the first reference conductor 55 A third equivalent transmission line model 23 is generated. The first main transmission line 211 of the first equivalent transmission line model 21 represents the equivalent element of the transmission line 53 , and the first sub-transmission line 212 represents the equivalent element of the frame body 571 . The second main transmission line 221 of the second equivalent transmission line model 22 represents the equivalent element of the first reference conductor 55 , and the second secondary transmission line 222 represents the equivalent element of the frame body 571 . The third main transmission line 231 of the third equivalent transmission line model 23 represents the equivalent element of the first reference conductor 55 , and the third sub-transmission line 232 represents the equivalent element of the frame body 571 . Furthermore, the first impedance unit 31 , the second impedance unit 32 and the third impedance unit 33 in the filter 501 are equivalent to the first impedance unit 31 , the second impedance unit 32 and the third impedance unit 31 in the equivalent filter circuit 202 in FIG. 4 . Three impedance units 33 .

In an embodiment of the present invention, the first equivalent transmission line model 21 , the second equivalent transmission line model 22 and the third equivalent transmission line are modified by changing the length and width of the transmission line 53 , the frame portion 571 and the slot portion 573 Characteristic impedances ( Z1 , Z2 , Z3 ) and electrical lengths ( θ1 , θ2 , θ3 ) of the model 23 . Then, the frequency at which the equivalent filter circuit 202 absorbs electromagnetic noise is adjusted by correcting the characteristic impedances ( Z1 , Z2 , Z3 ) and/or the electrical lengths ( θ1 , θ2 , θ3 ).

Please refer to FIG. 17 , which is a bottom view of the structure of a filter according to another embodiment of the present invention, and refer to FIGS. 7 , 12 and 13 at the same time. Compared with the filter 501 of the embodiment of FIG. 16 , the filter 502 of the embodiment of FIG. 17 further includes at least one fourth impedance unit 34 , at least one fifth impedance unit 35 and at least one sixth impedance unit 36 . The fourth impedance unit 34 , the fifth impedance unit 35 and the sixth impedance unit 36 are respectively disposed in the groove-shaped portion 573 . The left or right end of the first impedance unit 31 is connected to the first reference conductor 55 through the fourth impedance unit 34 , the left or right end of the second impedance unit 32 is connected to the first reference conductor 55 through the fifth impedance unit 35 , and the third impedance unit 33 The left end or the right end of is connected to the first reference conductor 55 through the sixth impedance unit 36 . The equivalent filter circuit 204 of FIG. 7 can be equivalently formed by the filter 502 . The fourth impedance unit 34 , the fifth impedance unit 35 and the sixth impedance unit 36 in the filter 502 are equivalent to the fourth impedance unit 34 , the fifth impedance unit 35 and the sixth impedance unit in the equivalent filter circuit 204 in FIG. 7 36. In the equivalent filter circuit 204 in FIG. 7 and the filter 502 in FIG. 17 , the first impedance unit 31 and the fourth impedance unit 34 on both sides thereof, the second impedance unit 32 and the fifth impedance unit 35 on both sides thereof and the third The impedance unit 33 and the sixth impedance units 36 on both sides thereof will respectively form a "π"-shaped impedance assembly unit.

Please refer to FIG. 18 for a bottom view of the structure of a filter according to another embodiment of the present invention, and refer to FIG. 9 , FIG. 12 and FIG. 13 at the same time. In the filter 503 in FIG. 18 , two or more first impedance units 31 are arranged on the first side 5711 of the frame part 571 , and two or more second impedance units 32 are arranged on the third side of the frame part 571 . On the side 5713, two or more third impedance units 33 are arranged on the second side 5712 of the frame part 571 or on the fourth side 5714 of the frame part 571. One end of each fourth impedance unit 34 is connected between two adjacent first impedance units 31 and the other end is connected to the first reference conductor 55 , and one end of each fifth impedance unit 35 is connected between two adjacent second impedance units 31 . The other end of the impedance units 32 is connected to the first reference conductor 55 , and one end of each sixth impedance unit 36 is connected between two adjacent third impedance units 33 and the other end is connected to the first reference conductor 55 . The equivalent filter circuit 206 of FIG. 9 can be equivalently formed by the filter 503 . In the equivalent filter circuit 206 of FIG. 9 and the filter 503 of FIG. 18 , the fourth impedance unit 34 connected between the two first impedance units 31 and the connection between the two first impedance units 31 and the two second impedance units 32 The sixth impedance unit 36 and the two third impedance units 33 connected between the fifth impedance unit 35 , the two second impedance units 32 and the two third impedance units 33 will respectively form a “T”-shaped impedance assembly unit.

Please refer to FIG. 19 for a bottom view of the structure of another embodiment of the filter of the present invention, and refer to FIGS. 10 , 12 and 13 at the same time. The equivalent filter circuit 207 of FIG. 10 can be equivalently formed by the filter 504 of FIG. 19 . Compared with the filter 500 of the embodiment shown in FIG. 14 , the first impedance unit 31 and the second impedance unit 32 are arranged on the frame body 571 , and the filter 504 of FIG. 19 has the first impedance unit 31 and the second impedance unit 32 arranged in the slot. In the shape portion 573 , the first side 5711 of the frame portion 571 is connected to the first reference conductor 55 through the first impedance unit 31 and the third side 5713 of the frame portion 571 is connected to the first reference conductor 55 through the second impedance unit 32 .

Please refer to FIG. 20 , which is a bottom view of the structure of a filter according to another embodiment of the present invention, and refer to FIGS. 11 , 12 and 13 at the same time. The equivalent filter circuit 208 of FIG. 11 can be equivalently formed by the filter 505 of FIG. 20 . Compared with the filter 504 in the embodiment shown in FIG. 19 , the filter 505 in FIG. 20 further includes at least one third impedance unit 33 . The third impedance unit 33 is disposed in the groove portion 573, the second side 5712 of the frame portion 571 is connected to the first reference conductor 55 through the third impedance unit 33, or the fourth side 5714 of the frame portion 571 passes through the third impedance unit 33 is connected to the first reference conductor 55 .

Please refer to FIG. 21 and FIG. 22 , which are a three-dimensional perspective view and a top view of the structure of a filter according to another embodiment of the present invention, respectively. In the present invention, the number of the transmission lines 53 of each filter 500, 501, 502, 503, 504, 505 may also be two. The two transmission lines 53 will form a pair of differential transmission lines. A differential mode signal and a common mode signal will be generated on the two transmission lines 53 . The differential mode signal is a data signal, and the common mode signal is a common mode noise. The filters 500/501/502/503/504/505 use the impedance units 31, 32, 33, 34, 35 and/or 36 to absorb common mode noise, so as to prevent the common mode noise from affecting the differential mode signal. transmission quality.

Please refer to FIG. 23 , which is a bottom view of the structure of another embodiment of each filter of the present invention. In the filter 500 of this embodiment, a second reference conductor 577 is further disposed in the hollow portion 575 of the slot-like structure 57 . The second reference conductor 577 is disposed in the hollow portion 575 corresponding to the position of the transmission line 53 , for example, the second reference conductor 577 is located directly below the transmission line 53 . Then, by the arrangement of the second reference conductor 577, the capacitive coupling effect between the transmission line 53 and the slot structure 57 is increased, so that the signal passing through the filter 500 can achieve better impedance matching, so as to achieve better signal quality . In this embodiment, the first impedance unit 31 and the second impedance unit 32 are disposed on the frame body portion 571 on both sides of the second reference conductor 577, and can be disposed on the frame body portion 571 in the manner of FIG. 14A and directly Connected to the frame body 571; alternatively, the third impedance unit 33 in this embodiment may also be disposed on the frame body 571 in the manner shown in FIG. 14B and connected to the frame body 571 through conductive through holes.

Of course, in addition to the filter 500 , other filters 501 , 502 , 503 , 504 or 505 may also be provided in the hollow portion 575 of the slotted structure 57 in order to increase the capacitive coupling effect between the transmission line 53 and the slotted structure 57 . A second reference conductor 577 is provided in the , which will not be described one by one here. The above descriptions are only preferred embodiments of the present invention and are not intended to limit the scope of implementation of the present invention. That is, all the shapes, structures, features and spirits described in the scope of the patent application of the present invention are equivalent changes and modifications. , shall be included in the scope of the patent application of the present invention.

200: Equivalent filter circuit 201: Equivalent filter circuit 202: Equivalent filter circuit 203: Equivalent filter circuit 204: Equivalent filter circuit 205: Equivalent filter circuit 206: Equivalent filter circuit 207: Equivalent filter circuit 208: Equivalent filter circuit 21: The first equivalent transmission line model 211: The first main transmission line 2111: Signal input port 2112: Signal output port 212: The first sub-transmission line 22: Second Equivalent Transmission Line Model 221: The second main transmission line 222: The second secondary transmission line 23: The third equivalent transmission line model 231: The third main transmission line 232: The third sub-transmission line 31: The first impedance unit 32: The second impedance unit 33: The third impedance unit 34: The fourth impedance unit 35: Fifth impedance unit 36: Sixth impedance unit 500: Filter 501: Filter 502: Filter 503: Filter 504: Filter 505: Filter 51: Substrate 53: Transmission line 55: First reference conductor 57: Slot structure 571: Frame part 5710: Gap 5711: First side 5712: Second side 5713: Third side 5714: Fourth side 573: grooved part 575: hollow part 577: Second reference conductor 59: Substrate 591: Conductive through hole

FIG. 1 is a circuit diagram of an embodiment of an equivalent filter circuit of the present invention.

FIG. 2 is a circuit diagram of another embodiment of an equivalent filter circuit of the present invention.

FIG. 3 is a circuit diagram of another embodiment of an equivalent filter circuit of the present invention.

FIG. 4 is a circuit diagram of another embodiment of an equivalent filter circuit of the present invention.

FIG. 5 is a circuit diagram of another embodiment of an equivalent filter circuit of the present invention.

FIG. 6 is a circuit diagram of another embodiment of an equivalent filter circuit of the present invention.

FIG. 7 is a circuit diagram of another embodiment of an equivalent filter circuit of the present invention.

FIG. 8 is a circuit diagram of another embodiment of an equivalent filter circuit of the present invention.

FIG. 9 is a circuit diagram of another embodiment of an equivalent filter circuit of the present invention.

FIG. 10 is a circuit diagram of another embodiment of an equivalent filter circuit of the present invention.

FIG. 11 is a circuit diagram of another embodiment of an equivalent filter circuit of the present invention.

12 is a perspective view of the structure of an embodiment of the filter of the present invention.

FIG. 13 is a top view of the structure of an embodiment of the filter of the present invention.

FIG. 14 is a bottom view of the structure of an embodiment of the filter of the present invention.

FIG. 14A is a cross-sectional view of the structure of an embodiment of the filter of the present invention.

FIG. 14B is a cross-sectional view of the structure of another embodiment of the filter of the present invention.

FIG. 15 is an enlarged view of the area A of FIG. 14 .

FIG. 16 is a bottom view of the structure of another embodiment of the filter of the present invention.

FIG. 17 is a bottom view of the structure of another embodiment of the filter of the present invention.

FIG. 18 is a bottom view of the structure of another embodiment of the filter of the present invention.

FIG. 19 is a bottom view of the structure of another embodiment of the filter of the present invention.

FIG. 20 is a bottom view of the structure of another embodiment of the filter of the present invention.

FIG. 21 is a structural perspective view of an embodiment of the filter of the present invention.

FIG. 22 is a top view of the structure of an embodiment of the filter of the present invention.

FIG. 23 is a bottom view of the structure of another embodiment of the filter of the present invention.

500: Filter

501: Filter

502: Filter

503: Filter

504: Filter

505: Filter

51: Substrate

53: Transmission line

55: first reference conductor

57: trough structure

Claims (24)

A filter that includes: a substrate; at least one transmission line disposed on a first surface of the substrate; and A first reference conductor is disposed on a second surface of the substrate and includes a slot-like structure inside, and the slot-like structure includes: a frame body; a groove-like portion surrounding the periphery of the frame portion; and a hollow portion formed in the frame portion; Wherein, at least one first impedance unit is connected to the frame body. The filter of claim 1, wherein the frame portion is a quadrilateral frame and includes a first side, a second side, a third side and a fourth side, and the first side corresponds to the first side. There are three sides, the second side corresponds to the fourth side, and the transmission line is projected across the first side and the third side of the frame portion. The filter according to claim 2, further comprising at least one second impedance unit, the first impedance unit is disposed on the first side of the frame body corresponding to the position of the transmission line, the second impedance unit Corresponding to the position of the transmission line, it is arranged on the third side of the frame body. The filter according to claim 3, further comprising at least one third impedance unit, and the third impedance unit is disposed on the second side or the fourth side of the frame portion. The filter according to claim 2, further comprising at least one third impedance unit, and the third impedance unit is disposed on the second side or the fourth side of the frame portion. The filter according to claim 1, further comprising at least one fourth impedance unit, the fourth impedance unit is disposed in the groove portion, and the left end or the right end of the first impedance unit is connected to the first impedance unit through the fourth impedance unit a reference conductor. The filter according to claim 3, further comprising at least one fourth impedance unit and at least one fifth impedance unit, the fourth impedance unit and the fifth impedance unit are arranged in the slot-shaped portion, the first impedance unit The left or right end of the second impedance unit is connected to the first reference conductor through the fourth impedance unit, and the left or right end of the second impedance unit is connected to the first reference conductor through the fifth impedance unit. The filter according to claim 5, further comprising at least one fourth impedance unit and at least one sixth impedance unit, the fourth impedance unit and the sixth impedance unit are respectively disposed in the slot-shaped portion, the first impedance unit The left or right end of the unit is connected to the first reference conductor through the fourth impedance unit, and the left or right end of the third impedance unit is connected to the first reference conductor through the sixth impedance unit. The filter according to claim 4, further comprising at least one fourth impedance unit, at least one fifth impedance unit and at least one sixth impedance unit, the fourth impedance unit, the fifth impedance unit and the sixth impedance unit respectively disposed in the slot-shaped portion, the left or right end of the first impedance unit is connected to the first reference conductor through the fourth impedance unit, and the left or right end of the second impedance unit is connected to the first reference conductor through the fifth impedance unit a reference conductor, the left end or the right end of the third impedance unit is connected to the first reference conductor through the sixth impedance unit. The filter according to claim 1, further comprising at least one fourth impedance unit, the fourth impedance unit is disposed in the slot-shaped portion, and one end of each fourth impedance unit is connected to two adjacent first The other end of an impedance unit is connected to the first reference conductor. The filter according to claim 3, further comprising at least one fourth impedance unit and at least one fifth impedance unit, the fourth impedance unit and the fifth impedance unit are disposed in the groove-shaped portion, each of the fourth impedance units and the fifth impedance unit One end of the impedance unit is connected between two adjacent first impedance units and the other end is connected to the first reference conductor, and one end of each fifth impedance unit is connected between two adjacent second impedance units and The other end is connected to the first reference conductor. The filter according to claim 5, further comprising at least one fourth impedance unit and at least one sixth impedance unit, the fourth impedance unit and the sixth impedance unit are respectively disposed in the slot-shaped portion, each of the first impedance units One end of the four impedance units is connected between two adjacent first impedance units and the other end is connected to the first reference conductor, and one end of each sixth impedance unit is connected between two adjacent third impedance units The other end is connected to the first reference conductor. The filter according to claim 4, further comprising at least one fourth impedance unit, at least one fifth impedance unit and at least one sixth impedance unit, the fourth impedance unit, the fifth impedance unit and the sixth impedance unit respectively disposed in the slot-shaped portion, one end of each of the fourth impedance units is connected between two adjacent first impedance units and the other end is connected to the first reference conductor, and one end of each of the fifth impedance units is connected between two adjacent second impedance units and the other end is connected to the first reference conductor, one end of each sixth impedance unit is connected between two adjacent third impedance units and the other end is connected to the first reference conductor. The filter of claim 1, wherein the slot-like structure further comprises a second reference conductor, and the second reference conductor is disposed in the hollow portion corresponding to the position of the transmission line. The filter of claim 1, wherein the number of the transmission lines is two to form a pair of differential transmission lines. The filter of claim 1, wherein the frame portion and the first reference conductor form an asymmetric coplanar stripline. A filter that includes: a substrate; at least one transmission line disposed on a first surface of the substrate; and A first reference conductor is disposed on a second surface of the substrate and includes a slot-like structure inside, and the slot-like structure includes: a frame body; a groove-like portion surrounding the periphery of the frame portion; and a hollow portion formed in the frame portion; Wherein, at least one first impedance unit is disposed in the groove portion and is connected to the frame portion and the first reference conductor. The filter of claim 17, wherein the frame portion is a quadrilateral frame and includes a first side, a second side, a third side and a fourth side, and the first side corresponds to the first side There are three sides, the second side corresponds to the fourth side, and the transmission line is projected across the first side and the third side of the frame portion. The filter according to claim 18, further comprising at least one second impedance unit, the first impedance unit is disposed in the slot-shaped portion corresponding to the position of the transmission line and is used for connecting the first impedance unit of the frame portion One side and the first reference conductor, the second impedance unit is disposed in the slot portion corresponding to the position of the transmission line and used to connect the third side of the frame portion and the first reference conductor. The filter as claimed in claim 19, further comprising at least one third impedance unit, the third impedance unit is disposed in the groove portion and used for connecting the second side of the frame portion and the first reference The conductor is used to connect the fourth side of the frame body and the first reference conductor. The filter according to claim 18, further comprising at least one third impedance unit, the first impedance unit is disposed in the slot-shaped portion corresponding to the position of the transmission line and used for connecting the first impedance unit of the frame portion one side and the first reference conductor, the third impedance unit is disposed in the slot-shaped portion and is used to connect the second side of the frame portion and the first reference conductor or to connect the frame portion of the the fourth side and the first reference conductor. The filter of claim 17, wherein the slot-like structure further comprises a second reference conductor, and the second reference conductor is disposed in the hollow portion corresponding to the position of the transmission line. The filter of claim 17, wherein the number of the transmission lines is two to form a pair of differential transmission lines. The filter of claim 17, wherein the frame portion and the first reference conductor form an asymmetric coplanar stripline.

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