CN208241640U - A kind of LTCC high-pass filter - Google Patents

Abstract

The utility model discloses an LTCC high-pass filter, which is a fifth-order filter composed of two capacitors and three inductances and a total of five reactance elements, and an LC series resonance is designed at the first inductance and the third inductance to form a transmission zero point , in order to increase the stop band suppression, realize the conductors of these inductors and capacitors are printed on the surface of LTCC raw ceramics, and make filters through drilling, filling, screen printing, lamination and sintering processes; use LTCC vertical interconnection The structure realizes the connection of these 7 reactive components; the inductor adopts vertical spiral inductors, and the connection between different layers is realized through vertical via holes; the capacitor adopts metal-conductor-metal structure; the inductor and capacitor are also connected by vertical interconnection. There is no whole ground layer in the LTCC substrate, but it is connected to the ground through the side electrodes of the LTCC. The filter is small in size, low in cost, low in-band insertion loss, high in out-of-band suppression, high in-band stability, and good selectivity. It is easy for mass production of devices and can be widely used in the field of modern wireless communication.

Description

A LTCC high-pass filter

technical field

The utility model relates to the filter field, in particular to an LTCC high-pass filter.

Background technique

At present, with the rapid development of wireless communication technology and the continuous expansion of business scope, people's demand for wireless products is growing rapidly. High-pass filters play an important role in these products, and have made continuous progress with the development of communication technology. Its main function is to reduce the passage of low-frequency signals as much as possible while passing signals higher than a certain frequency with low loss. A good high-pass filter not only requires low in-band loss and high out-of-band rejection, but also requires as small a volume as possible and stable performance.

The traditional high-pass filter generally adopts a planar structure, and the reactive components such as capacitors and inductors are arranged in a certain order to form a filter, which not only occupies a relatively large area, but also has a large insertion loss of the filter, and the performance is not very ideal. Meet the requirements of radio frequency circuits for device miniaturization and high performance.

Low-temperature co-fired ceramics is an electronic packaging technology that uses a multilayer ceramic process to place passive components inside a ceramic dielectric. LTCC technology has outstanding advantages in terms of cost, miniaturization, low-impedance technology, design diversification and flexibility, and high-frequency performance. LTCC uses a multi-layer ceramic lamination process and adopts low-temperature co-firing to ensure that metals with high conductivity (gold, silver, etc.) can be used for internal circuit printing inside the medium, thereby ensuring better conductive loss.

Utility model content

Aiming at the deficiencies of the prior art, the utility model proposes an LTCC high-pass filter, which adopts the unique vertical interconnection structure of the LTCC technology, which can significantly reduce the size of the components; at the same time, effectively utilizes the gap between the inductor and the capacitor The coupling effect forms a transmission zero point in the stop band, the performance of the stop band is improved, and a high-pass filter with excellent performance is designed with fewer orders. The specific technical scheme is as follows:

A kind of LTCC high-pass filter, comprises input electrode, output electrode and external ground electrode, is characterized in that, comprises the first electric capacity C1 and the second electric capacity C2 of serial connection, the first inductance L1 of parallel connection, the second inductance L2, the first The three inductors L3 and the third capacitor C3 and the fourth capacitor C4 which form series resonance with the first and third inductors L1 and L3 respectively, realize that the conductors of these inductors and capacitors are printed on the surface of the LTCC raw ceramics, and are punched and filled Hole, screen printing, lamination and sintering process to make the filter; LTCC vertical interconnection structure is used to realize the connection of these 7 reactance components; the inductor adopts vertical spiral inductor, and the connection between different layers is realized through vertical via holes; the capacitor adopts Metal-conductor-metal type structure; vertical interconnection is also used between inductors and capacitors;

It includes a multi-layer LTCC ceramic substrate, wherein the input electrode and the output electrode are respectively arranged at opposite ends of the filter in the length direction, and the ground electrode is arranged outside the middle of the filter in the length direction;

The inductor and capacitor adopt a vertical interconnection structure, the capacitor is located above the filter body structure, and the inductor is located below the filter body structure;

The first, second, and third inductors L1, L2, and L3 are realized by spiral inductors on multilayer ceramic media. The metal conductors on different ceramic media are connected through through holes, and the line length and line width of each layer of the spiral inductor line are adjusted. To adjust each capacitance value;

The first, second, third, and fourth capacitors C1, C2, C3, and C4 are realized by the planar capacitor plates of multilayer ceramic dielectric layers, and the capacitor plates between different ceramic dielectric layers are realized by the mutual coupling between the plates Interconnection, adjust the capacitance value by adjusting the size of the plate;

The circuit part of the filter has 11 layers in total, and the first capacitor and the second capacitor C1 and C2 are located on the first, second and third layers of the three-dimensional circuit of the filter; the first capacitor and the second capacitor C1 and C2 pass through the third layer The metal plate on the top is coupled and connected;

The start of the first inductor L1 is on the 4th and 5th layers, and is connected to the metal plate on the second layer of the first capacitor C1 through a through hole, and the end is on the 6th and 7th layers, and is connected to the ground electrode on the side of the filter connected;

The start of the second inductor L2 is on the 8th and 9th layers, and is connected to the metal plate of the third layer through a through hole, and the end is on the 10th and 11th layers, and is connected to the ground electrode on the side of the filter;

The start of the third inductor L3 is on the 4th and 5th layers, and is connected to the metal plate on the second layer of the second capacitor C2 through a through hole, and the end is on the 6th and 7th layers, and is connected to the ground electrode on the side of the filter connected;

The second layer plate of the first capacitor C1 is coupled with the connecting plate of the third layer of the filter three-dimensional circuit to form a third capacitor C3, which is connected in series with the first inductor L1 to form a series resonance and generate a transmission zero point;

The second plate of the second capacitor C2 is coupled with the connecting plate of the third layer of the three-dimensional filter circuit to form a fourth capacitor C4, which is connected in series with the third inductor L3 to form a series resonance and generate a transmission zero point.

Further, the first capacitor C1 is the input end of the filter; the second capacitor C2 is the output end of the filter; one end of the first inductance L1 is connected to the second layer plate of the first capacitor C1, and the other end is connected to the ground; One end of the third inductance L3 is connected to the second layer plate of the second capacitor C2, and the other end is connected to the ground; one end of the second inductance L2 is connected to the plates of the first and second capacitors C1 and C2 of the third layer , and the other end is connected to ground.

Furthermore, the structure of the first capacitor C1 and the second capacitor C2 are mirror-symmetrical, and the size of the plates is the same; the structure of the first inductor L1 and the third inductor L3 are mirror-symmetrical, and both are four-layer spiral inductors with the same size.

Further, the zero points formed by the two series resonances are at the same position, and the resonant frequency is adjusted by adjusting the values of the first inductance L1 and the third inductance L3 or the values of the third capacitor C3 and the fourth capacitor C4 to meet the impedance Bring requirements.

Further, the overall size of the filter is 3.2mm×1.6mm×0.95mm.

Further, the cutoff frequency of the filter is 0.5GHz, the maximum loss in the passband is 1.6dB, and the attenuation is greater than 25dB in the frequency range of 0-0.4GHz.

The beneficial effects of the utility model are as follows:

The utility model makes full use of the multi-layer ceramic stacking process, and adopts the unique vertical interconnection structure of LTCC technology, which can significantly reduce the size of the components; at the same time, it effectively utilizes the coupling effect between the inductance and the capacitance to form a transmission zero point in the stop band , the stopband performance is improved, and a high-pass filter with excellent performance is designed with fewer orders and components.

Description of drawings

Fig. 1 is the equivalent circuit schematic diagram of the LTCC high-pass filter of the present utility model;

Fig. 2 is the outline drawing of the LTCC high-pass filter of the present utility model;

Fig. 3 is the front structural diagram of the LTCC high-pass filter of the present utility model;

Fig. 4 is the first layer 3D structural diagram of the LTCC high-pass filter of the present utility model;

Fig. 5 is the 2nd layer 3D structural diagram of the LTCC high-pass filter of the present utility model;

Fig. 6 is the 3rd layer 3D structural diagram of the LTCC high-pass filter of the present utility model;

Fig. 7 is the 4th layer 3D structural diagram of the LTCC high-pass filter of the present utility model;

Fig. 8 is the 5th layer 3D structural diagram of the LTCC high-pass filter of the present utility model;

Fig. 9 is the 6th layer 3D structural diagram of the LTCC high-pass filter of the present utility model;

Fig. 10 is the 7th layer 3D structural diagram of the LTCC high-pass filter of the present utility model;

Fig. 11 is the 8th layer 3D structural diagram of the LTCC high-pass filter of the present utility model;

Fig. 12 is the 9th layer 3D structural diagram of the LTCC high-pass filter of the present utility model;

Fig. 13 is the 10th layer 3D structural diagram of the LTCC high-pass filter of the present utility model;

Fig. 14 is the 11th layer 3D structural diagram of the LTCC high-pass filter of the present utility model;

Fig. 15 is the S11 simulation result figure of the LTCC high-pass filter of the present utility model;

Fig. 16 is the S21 simulation result figure of the LTCC high-pass filter of the present utility model;

Fig. 17 is a simulation result diagram of the standing wave ratio of the LTCC high-pass filter of the present invention.

Detailed ways

The utility model will be described in detail below according to the accompanying drawings and preferred embodiments, and the purpose and effect of the utility model will become clearer. The utility model will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model, and are not intended to limit the utility model.

Fig. 1 is the equivalent circuit schematic diagram of the LTCC high-pass filter of the present utility model, as shown in Figure 1, the LTCC high-pass filter of the present utility model comprises two basic capacitors C1, C2; Three inductors L1, L2, L3; Two series resonant capacitors C3, C4. Capacitors C1, C2, inductors L1, L2, L3 are connected together according to a certain topology relationship to realize the basic function of the high-pass filter. The first inductance L1 and the third inductance L3 form a series resonance with the third capacitor C3 and the fourth capacitor C4 respectively, forming a transmission zero point in the stop band, and the position of the transmission zero point can be changed by changing the values of the inductors L1, L3 and capacitors C3 and C4 , to improve the performance of the filter.

Fig. 2 is the outline drawing of the high-pass filter realized by LTCC technology. The filter form factor includes an LTCC ceramic substrate. Solderable metal conductor strips are printed on the outside of the middle in the length direction of the substrate as the ground electrode GND of the filter; the opposite ends of the filter substrate in the length direction are covered with weldable metal conductors as the input electrode IN and output of the filter Electrode OUT. When using it, you only need to solder the filter to the corresponding circuit board through the metal electrode according to the correct method.

In this embodiment, the external dimensions of the LTCC high-pass filter are 3.2mm×1.6mm×0.95mm, the relative dielectric constant of the LTCC ceramic medium used is 9.8, the loss tangent is 0.003, and the thickness of each layer of ceramic medium is 0.05mm. The conductor material is metallic silver.

Figure 3 is a front view structure diagram of the LTCC high-pass filter. The circuit as a whole adopts a vertical interconnection structure. In Fig. 3, the four capacitors of the filter all adopt the MIM structure and are interconnected through the coupling between the plates. The four capacitors are set on layers 1, 2, and 3 of the LTCC filter circuit. The main purpose is to reduce their parasitic capacitance to ground and improve filter performance. The first capacitor C1 and the second capacitor C2 are left-right mirror-symmetrical in structure, and the size of the plates and the capacitance of the capacitors are equal. The plates of the capacitors C1 and C2 are respectively located on the first, second and third layers of the filter circuit. The first and third layers of capacitor C1 are connected to the input end of the filter; the first and third layers of capacitor C2 are connected to the output end of the filter. The second layer plate of the capacitor C1 is connected to the second layer plate of the capacitor C2 through the plate coupling of the third layer of the circuit, forming a series connection of the capacitor C1 and the capacitor C2. At the same time, capacitor C3 is coupled from the second plate of capacitor C1 to the connecting plate of the third layer, and connected to one end of inductor L1 through a through hole to form a series resonance between L1 and C3; the second plate of capacitor C2 is connected to the third layer. The board couples out the capacitor C4, which is connected to one end of the inductor L3 through a through hole to form a series resonance between L3 and C4.

In Figure 3, the inductance of the filter is set on the 4th, 5th, 6th, and 7th layers of the circuit and the 8th, 9th, 10th, and 11th layers of the circuit. Inductors L1, L2, and L3 all adopt a 4-layer spiral structure, and metal conductors on different dielectric layers are connected through through holes. The inductance L1 and the inductance L3 are mirror-symmetrical in structure, the line width and line length of the metal conduction band are equal, and the inductance values L1 and L3 are equal. The starting end of the inductor L1 is on the 4th and 5th layers, and is connected to the metal plate on the 2nd layer of the first capacitor C1 through a through hole, and the end is on the 6th and 7th layers, and is connected to the ground electrode on the side of the filter; The starting end of the inductor L2 is on the 8th and 9th layers, and is connected to the metal connection plate of the third layer through a through hole, and the end is on the 10th and 11th layers, and is connected to the ground electrode on the side of the filter; the starting end of the inductor L3 It is on the 4th and 5th layers and is connected to the metal plate on the second layer of the second capacitor C2 through a through hole, and the end is on the 6th and 7th layers and is connected to the ground electrode on the side of the filter. The specific structures of filter capacitors and inductors are described in Figure 4-14.

Fig. 15-17 is the simulation test result diagram of the utility model LTCC high-pass filter. As shown, the cutoff frequency of this high-pass filter is 0.5GHz. The insertion loss in the passband is not greater than 1.6dB, the stopband suppression is not less than 25dB in the frequency range DC-0.4GHz, and the standing wave ratio (VSWR) in the passband is not greater than 2.5.

In summary, the LTCC high-pass filter provided by the utility model has the characteristics of small size, small insertion loss, and high out-of-band suppression, and can be patched and welded, and is easy to integrate with other microwave components. Moreover, the utility model is based on LTCC technology, has low manufacturing cost and is suitable for mass production.

Those of ordinary skill in the art can understand that the above description is only a preferred example of the utility model, and is not intended to limit the utility model. Although the utility model has been described in detail with reference to the foregoing examples, for those skilled in the art, the It is still possible to modify the technical solutions recorded in the foregoing examples, or perform equivalent replacements for some of the technical features. All modifications, equivalent replacements, etc. within the spirit and principles of the utility model shall be included in the protection scope of the utility model.

Claims (6)

1. a kind of LTCC high-pass filter, including input electrode, output electrode and external grounding electrode, which is characterized in that including The first capacitor C1 of series connection and the second capacitor C2, the first inductance L1 being connected in parallel, the second inductance L2, third inductance L3 with And the third capacitor C3 and the 4th capacitor C4 of series resonance are respectively formed with first, third inductance L1, L3, realize these inductance, Filtering is made on LTCC green surface, and by punching, filling perforation, wire mark, lamination and sintering process in the conductor printing of capacity cell Device；The connection of this 7 reactance components is realized using LTCC vertical interconnecting structure；Inductance uses vertical spin inductance, by vertical Through-hole realizes the connection between different layers；Capacitor uses metal-conductor-metallic type structure；Also using vertical between inductance and capacitor Straight mutual downlink connection；

Including multilayer LTCC ceramic substrate, wherein it is long that the input terminal electrode and output terminal electrode are respectively arranged on the filter The opposite end on direction is spent, the ground connection termination electrode is set on the outside of the middle part on filter length direction；

Inductance, capacitor use vertical interconnecting structure, and capacitor is located above filter housing construction, and inductance is located at filter body knot Below structure；

First, second, third inductance L1, L2, L3 is realized using the spiral inductance on multiple layer ceramic dielectric, on different ceramic dielectrics Metallic conductor connected by through-hole, by adjusting the wire length of every layer of spiral inductance line, line width adjusts each capacitance；

First, second, third, fourth capacitor C1, C2, C3, C4 passes through the plane capacitance pole plate realization of multiple layer ceramic dielectric layer, no With the capacitor plate between ceramic dielectric layer by the intercoupling realization interconnection between pole plate, adjusted by adjusting the size of pole plate Save each capacitance；

The circuit part of the filter shares 11 layers, and first capacitor, second capacitor C1, C2 are located at filter three-dimensional circuit 1st, 2,3 layer；First capacitor, second capacitor C1, C2 are connected by the metal polar plate coupling on the 3rd layer；

The beginning of first inductance L1 is connected on the 4th, 5 layer, and with the metal polar plate on the 2nd layer of first capacitor C1 by through-hole, End is connected on the 6th, 7 layer, and with the grounding electrode of filter flanks；

The beginning of second inductance L2 is connected on the 8th, 9 layer, and through through-hole with the metal polar plate of third layer, end the 10th, On 11 layers, and it is connected with the grounding electrode of filter flanks；

The beginning of third inductance L3 is connected on the 4th, 5 layer, and with the metal polar plate on the 2nd layer of the second capacitor C2 by through-hole, End is connected on the 6th, 7 layer, and with the grounding electrode of filter flanks；

The 2nd layer of pole plate of first capacitor C1 and the 3rd layer of filter three-dimensional circuit of connection pole plate are coupled out third capacitor C3, with the One inductance L1 is connected in series, and forms series resonance, generates transmission zero；

The 2nd layer of pole plate of second capacitor C2 and the 3rd layer of filter three-dimensional circuit of connection pole plate are coupled out the 4th capacitor C4, with the Three inductance L3 are connected in series, and form series resonance, generate transmission zero.

2. LTCC high-pass filter according to claim 1, which is characterized in that first capacitor C1 is the input of filter End；Second capacitor C2 is the output end of filter；One end of first inductance L1 is connected to the 2nd layer of pole plate of first capacitor C1, separately One end is connected with ground；One end of third inductance L3 is connected to the 2nd layer of pole plate of the second capacitor C2, and the other end is connected with ground；Second One end of inductance L2 is connected on the 3rd layer of the pole plate of first, second capacitor C1, C2, and the other end is connected with ground.

3. LTCC high-pass filter according to claim 1, which is characterized in that first capacitor C1, the second capacitor C2 are being tied It is in mirror symmetry on structure, plate dimensions are identical；First inductance L1, third inductance L3 are in mirror symmetry in structure, are all four layers Spiral inductance, size are identical.

4. LTCC high-pass filter according to claim 3, which is characterized in that the zero of the formation of series resonance described in two Point is in same position, by adjusting the value of the first inductance L1 and third inductance L3 or the value of third capacitor C3 and the 4th capacitor C4 Resonance frequency is adjusted, to meet stopband requirement.

5. LTCC high-pass filter according to claim 1, which is characterized in that the overall dimensions of filter be 3.2mm × 1.6mm×0.95mm。

6. LTCC high-pass filter according to claim 1, which is characterized in that the cutoff frequency of the filter is 0.5GHz, maximum loss is 1.6dB in passband, and in frequency range 0-0.4GHz, decaying is all larger than 25dB.