Summary of the invention
The object of the present invention is to provide the chip low temperature co-fired ceramic co-mode filter that a kind of differential mode impedance is little, production cost is low.
To achieve these goals, technical scheme of the present invention is:the chip low temperature co-fired ceramic co-mode filter, the green band that it is become by curtain coating is stacked in makes the LTCC body together, be printed with n layer left coil and right coil in the LTCC body, n 〉=5, n layer, the 1st layer are respectively the pin layer, and (annotate:one deck of going up most shown in Fig. 2 is the n layer, i.e. basecoat; Be because of Fig. 4-6 be n layer figure); Wherein an end of the right coil of adjacent one deck is linked to each other by joint and (illustrates:among Fig. 2 on an end of the left coil of one deck and described wherein one deck, figure coupling place is an end, the joint is the other end in the figure), on described wherein one deck on the other end of the right coil of adjacent one deck and described wherein one deck the other end of the left coil of the last layer of adjacent one deck link to each other by joint; It is characterized in that: an end of the left coil of described wherein one deck be connected the joint that an end of the right coil of the last layer of adjacent one deck is connected on an end and the described wherein one deck of the left coil of adjacent one deck on an end of the right coil of adjacent one deck connects on one deck wherein joint and described wherein one deck and open by the joint corner part is interlaced, the other end of the right coil of described wherein one deck be connected the right coil of adjacent one deck on joint and the described wherein one deck of the other end connection of the left coil of adjacent one deck on one deck wherein the other end be connected the joint that the other end of the left coil of the last layer of adjacent one deck is connected on one deck wherein and open by the joint corner part is interlaced.
It is overlapped over interlaced that described n layer left coil and right coil, the left coil of adjacent layer and right coil remove the joint corner part.
Described n layer left coil and right coil, wherein the both ends of left coil of one deck and right coil are right angle portion, then the both ends of left coil of another adjacent with it layer and right coil are respectively the joint corner part, the two joint corner parts at the left coil two ends of described another layer are opposite with the corner direction of the two joint corner parts at right coil two ends and leave spacing, and the corner direction of the two joint corner parts at the left coil two ends of described another layer is identical.
The invention has the beneficial effects as follows:
1), owing to adopted high Q value, low-loss low-temperature co-burning ceramic material, the Sdd21 parameter of resulting common-mode filter is not subjected to the influence of frequency substantially within the scope of 1GHz, its value is minimum; Compare with ferrite, its performance as shown in Figure 5, high frequency performance of the present invention is even more ideal.
2), the neighbouring coupling layer of the structure of traditional low temperature co-fired ceramic co-mode filter must depart from certain distance (joint employing parallel construction), with joint (via hole) short circuit of avoiding connecting levels, the performance of this structure depends on the distance between centers of tracks level of processing of processing line to a great extent, the area of Non-overlapping Domain Z is big more, then the area of the coupling regime of coil formation is more little, electromagnetic leakage is many more, and the differential mode impedance of device is also just big more, and performance reduces.
Joint of the present invention has adopted that corner part is interlaced to be opened, the coil overwhelming majority overlaids of levels, and being staggeredly stacked of neighbouring two-layer repetition, the area of Non-overlapping Domain Z is little; Can satisfy the inductance value requirement of single inductance on the one hand, guarantee enough stiffness of couplings between two coupling inductances, obtain not being subjected to the stiffness of coupling of processes horizontal constraints; On the other hand, reduced electromagnetic leakage, obtained differential mode impedance behavior (the differential mode impedance is less) preferably, can not cause loss signal.
3), joint of the present invention has adopted that corner part is interlaced to be opened, the area of Non-overlapping Domain Z is little, thereby avoided the minimum line pitch problems dexterously, the area of coupling regime is not subjected to the restriction of processing line spacing level and reduces, distance between centers of tracks is required to reduce, the processes difficulty is low, and common thick film screen printing technological level can reach processing request.Under the processing conditions of peer-level, performance is than traditional low temperature co-fired ceramic co-mode filter excellent performance, as shown in Figure 6.
4), because the ceramic-type filter in actual process is made, is printed conductor slurry on ceramic substrate, with low cost; Because each layer structure used in the present invention alternately repeats, only need a spot of silk screen to get final product simultaneously, reduced the mask expense, production cost reduces greatly.
Description of drawings
Fig. 1 is the vertical view of traditional low temperature co-fired ceramic co-mode filter structure.
Fig. 2 is a structural representation of the present invention.
Fig. 3 is a vertical view of the present invention.
Fig. 4-the 1st, the 1st layer of figure of preparation process of the present invention;
Fig. 4-the 2nd, the 2nd layer of figure of preparation process of the present invention;
Fig. 4-the 3rd, the odd-level figure of preparation process the 2nd to n-1 of the present invention (natural numbers of n 〉=5);
Fig. 4-the 4th, the even level figure of preparation process the 2nd to n-1 of the present invention;
Fig. 4-the 5th, preparation process n-1 layer figure of the present invention (illustrate: when n-1 was even number, Fig. 4-5 was Fig. 4-4);
Fig. 4-the 6th, preparation process n layer figure of the present invention.
Fig. 5 is the poor common mode S parameter comparison diagram that chip low temperature co-fired ceramic co-mode filter of the present invention is compared with ferrite device.
Fig. 6 is chip low temperature co-fired ceramic co-mode filter of the present invention and the impedance behavior comparison diagram of traditional low temperature co-fired ceramic co-mode filter under equal process conditions.
Fig. 7 (a) is the difference mode signal equivalent circuit diagram.
Fig. 7 (b) is the common-mode signal equivalent circuit diagram.
Among the figure: 1-LTCC body, the left coil that 2-is the 1st layer, the right coil that 3-is the 1st layer, the left coil of 4-n layer, the left coil of 5-n-1 layer, 6-joint corner part, the right coil of 7-n layer, 8-joint, the right coil of 9-n-1 layer.
Embodiment
As Fig. 2, shown in Figure 3, (n is 7 to the chip low temperature co-fired ceramic co-mode filter in this example, every layer printing is shown in Fig. 4-1, Fig. 4-2, Fig. 4-3, Fig. 4-4, Fig. 4-5, Fig. 4-6), the green band that it is become by curtain coating is stacked in makes LTCC body 1 together, be printed with 7 layers of left coil and right coil in the LTCC body, the 7th layer, the 1st layer is respectively the pin layer; One end of the 7th layer left coil 4 is linked to each other by joint 8 with an end of the 6th layer right coil 9 and (illustrates: among Fig. 2, figure coupling place is an end, the joint is the other end in the figure, and pin is the outer end), the other end of the 6th layer right coil 9 is linked to each other by joint with the other end of the 5th layer left coil; The other end of the 7th layer right coil 7 is linked to each other by joint with the other end of the 6th layer left coil 5, and an end of the 6th layer left coil 5 is linked to each other by joint with an end of the 5th layer right coil; The outer end of the 7th layer right coil 7 is a pin, and the outer end of the 7th layer left coil 4 is a pin;
One end of the 5th layer left coil is linked to each other by joint with an end of the 4th layer right coil, and the other end of the 4th layer right coil is linked to each other by joint with the other end of the 3rd layer left coil; The other end of the 5th layer right coil is linked to each other by joint with the other end of the 4th layer left coil, and an end of the 4th layer left coil is linked to each other by joint with an end of the 3rd layer right coil;
One end of the 4th layer left coil is linked to each other by joint with an end of the 3rd layer right coil, and the other end of the 3rd layer right coil is linked to each other by joint with the other end of the 2nd layer left coil; The other end of the 4th layer right coil is linked to each other by joint with the other end of the 3rd layer left coil, and an end of the 3rd layer left coil is linked to each other by joint with an end of the 2nd layer right coil;
One end of the 3rd layer left coil is linked to each other by joint with an end of the 2nd layer right coil, and the other end of the 2nd layer right coil is linked to each other by joint with the other end of the 1st layer left coil; The other end of the 3rd layer right coil is linked to each other by joint with the other end of the 2nd layer left coil, and an end of the 2nd layer left coil is linked to each other by joint with an end of the 1st layer right coil; The outer end of the 1st layer left coil is a pin, and the outer end of the 1st layer right coil is a pin.
The characteristics of this embodiment of the present invention are: an end of the 7th layer left coil 4 is a joint corner part 6, the other end of the 7th layer right coil 7 is the joint corner part, and the joint corner part 6 of the 7th layer left coil 4 is opposite with the corner direction of the joint corner part of the 7th layer right coil 7; The both ends of the right coil 9 of the 6th layer left coil 5 and the 6th layer are right angle portion, the both ends part interval overlapping of the right coil 9 of the 6th layer left coil 5 and the 6th layer; The both ends of the right coil of the 5th layer left coil and the 5th layer are the joint corner part, the corner direction of the two joint corner parts at the 5th layer left coil two ends and the two joint corner parts at the 5th layer right coil two ends is opposite and leave spacing, and the corner direction of the two joint corner parts at the 5th layer left coil two ends is identical; The 4th layer, the 2nd layer the left coil and the structure of right coil are identical with the structure of the 6th layer left coil and right coil, and the 3rd layer the left coil and the structure of right coil are identical with the structure of the 5th layer left coil and right coil; The other end of the 1st layer left coil is the joint corner part, and an end of the 1st layer right coil is the joint corner part, and the joint corner part of the 1st layer left coil is opposite with the corner direction of the joint corner part of the 1st layer right coil;
The left coil of the levels of 7 layers of left coil and right coil and right coil be orientation overlapping (remove joint corner part interlaced over) mutually up and down;
The joint that the joint 8 that one end of one end of the 7th layer left coil 4 and the 6th layer right coil 9 is connected and an end of the 6th layer left coil are connected with an end of the 5th layer right coil is by the joint corner part 6 of an end of the 7th layer left coil 4, the 5th layer interlaced the opening of joint corner part of an end of right coil; The joint that the joint that the other end of the other end of the 7th layer right coil 7 and the 6th layer left coil 5 is connected is connected with the other end of the other end of the 6th layer right coil and the 5th layer left coil is by the joint corner part of the other end of the 7th layer right coil, the 5th layer interlaced the opening of joint corner part of the other end of left coil;
The joint that the joint that one end of one end of the 6th layer left coil and the 5th layer right coil is connected and an end of the 5th layer left coil are connected with an end of the 4th layer right coil is by the joint corner part of an end of the 5th layer right coil, the 5th layer interlaced the opening of joint corner part of an end of left coil; The joint that the joint that the other end of the other end of the 6th layer right coil and the 5th layer left coil is connected is connected with the other end of the other end of the 5th layer right coil and the 4th layer left coil is by the joint corner part of the other end of the 5th layer left coil, the 5th layer interlaced the opening of joint corner part of the other end of right coil;
The joint that the joint that one end of one end of the 5th layer left coil and the 4th layer right coil is connected and an end of the 4th layer left coil are connected with an end of the 3rd layer right coil is by the joint corner part of an end of the 5th layer left coil, the 3rd layer interlaced the opening of joint corner part of an end of right coil; The joint that the joint that the other end of the other end of the 5th layer right coil and the 4th layer left coil is connected is connected with the other end of the other end of the 4th layer right coil and the 3rd layer left coil is by the joint corner part of the other end of the 5th layer right coil, the 3rd layer interlaced the opening of joint corner part of the other end of left coil;
The joint that the joint that one end of one end of the 4th layer left coil and the 3rd layer right coil is connected and an end of the 3rd layer left coil are connected with an end of the 2nd layer right coil is by the joint corner part of an end of the 3rd layer right coil, the 3rd layer interlaced the opening of joint corner part of an end of left coil; The joint that the joint that the other end of the other end of the 4th layer right coil and the 3rd layer left coil is connected is connected with the other end of the other end of the 3rd layer right coil and the 2nd layer left coil is by the joint corner part of the other end of the 3rd layer left coil, the 3rd layer interlaced the opening of joint corner part of the other end of right coil;
The joint that the joint that one end of one end of the 3rd layer left coil and the 3rd layer right coil is connected and an end of the 3rd layer left coil are connected with an end of the 1st layer right coil is by the joint corner part of an end of the 3rd layer left coil, the 1st layer interlaced the opening of joint corner part of an end of right coil; The joint that the joint that the other end of the other end of the 3rd layer right coil and the 2nd layer left coil is connected is connected with the other end of the other end of the 2nd layer right coil and the 1st layer left coil is by the joint corner part of the other end of the 3rd layer right coil, the 1st layer interlaced the opening of joint corner part of the other end of left coil.
The present invention also can adopt n=5,6,8,9,10,11 or 12 etc., and its version can adopt the version of n=7, analogizes according to the version of n=7.
No matter Non-overlapping Domain Z (promptly by the interlaced position of opening of joint corner part) is placed on coil long limit, minor face or the corner of (or claiming interior electrode), all can play aforesaid effect, and Fig. 2, Fig. 3 only are preferred versions of the present invention.
The manufacturing of chip low temperature co-fired ceramic co-mode filter following (utilizing existing LTCC Technology):
1, chooses low-temperature co-fired ceramic medium material, adopt curtain coating to make the green band.The purpose of curtain coating is that ceramic powder is changed into the green band that is easy to process.
2, the processing of green band, perforation: give birth to band and become standard size, utilize mechanical stamping, boring or laser drilling to form through hole by cutting off apparatus processing.The hole is used on the different layers with interconnection circuit.Go back communications centre molding jig hole in this stage, the aligning when helping lamination.
3, through hole is filled: modes such as thick film screen printing, porous stone perfusion that conductor dbus such as silver slurry are crossed pour into give birth to in the hole of holding successfully.
4, printing: adopt traditional thick film silk screen printing and computer directly to describe, conductor paste is printed and dries.Every layer printing is shown in Fig. 4-1, Fig. 4-2, Fig. 4-3, Fig. 4-4, Fig. 4-5, Fig. 4-6.
5, cutting: will finish the semi-finished product of preceding road technology, and utilize mode cutting and separating such as laser, saw, hot cutter to become single common-mode filter semi-finished product.
6, sintering: the semi-finished product inspection of single common-mode filter (substrate layer), arrangement and aligning different layers, the mating holes in making every layer are with one heart and prepare lamination; During the lamination, arrangement and the substrate layer of aiming at be in the same place by hot pressing (being generally 70 ℃, following 10 minutes of 3000psi); A step is burnt lamination altogether then: at 5 minutes~15 minutes lamination is burnt altogether to peak temperature (being generally 850 ℃), finish device main body.
7, coating electrode: relevant position coating electrode on the common-mode filter behind the sintering, the circuit of inside is drawn.
8, electroplate: behind the coating electrode process silver ink firing, but form protection layer (as nickel tin layer) at electrode surface,, make common-mode filter can utilize the technology of Surface Mount to be applied as weld interface with plating mode.
The common-mode filter basic principle:
Fig. 7 (a) is the difference mode signal equivalent circuit diagram, Fig. 7 (b) is the common-mode signal equivalent circuit diagram, and Fig. 7 (a), Fig. 7 (b) are the topological structure of common-mode filter, when two paths of signals passes through two coupling coils, can produce mutual inductance M, cause the equivalent electric sensibility reciprocal of single coil to change.
When the differential mode signal passed through, mutual inductance M magnetic direction was opposite with the magnetic direction that single coil produces, and the equivalent inductance quantitative change of single coil is L-M, and inductance value reduces, and signal becomes easier to be passed through.
When common-mode signal was passed through, mutual inductance M magnetic direction was identical with the magnetic direction that single coil produces, and the equivalent inductance quantitative change of single coil is L+M, and inductance value increases, and signal becomes and is difficult for passing through.
Be transmitted as the circuit of differential mode for signal, noise signal is the common mode form.By the appropriate design loop construction, can make M approach L, produce following result:
(1) when the differential mode signal passed through, coil inductance was close to 0, and signal can pass through smoothly.
(2) when common mode mould signal passed through, coil inductance was L+M, and loss of signal increases, and has effectively suppressed noise.
The above is the preferred embodiments of the invention, is not limited to the present invention.Especially for the exclusive Non-overlapping Domain Z syndeton of the present invention (promptly opening), for a person skilled in the art, various forms change and change in location can be arranged by the joint corner part is interlaced.Within the spirit and principles in the present invention all, any modification of being done, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.