CN114362707A

CN114362707A - LTCC miniaturized duplexer

Info

Publication number: CN114362707A
Application number: CN202111495358.2A
Authority: CN
Inventors: 邢孟江; 代传相; 杨晓东; 邢孟道; 刘永红
Original assignee: Yangtze River Delta Research Institute of UESTC Huzhou
Current assignee: Yangtze River Delta Research Institute of UESTC Huzhou
Priority date: 2021-12-09
Filing date: 2021-12-09
Publication date: 2022-04-15
Also published as: GB2615395A; GB202218140D0

Abstract

The invention relates to an LTCC (Low temperature Co-fired ceramic) miniaturized duplexer, belonging to the technical field of duplexers. The low-pass filter circuit comprises inductors connected in series between a common input port and a low-frequency output port, a capacitor connected with a ground port is connected between two adjacent inductors, a high-pass filter circuit comprises a capacitor connected in series between the common input port and the high-frequency output port, and an inductor connected with the ground port is connected between two adjacent capacitors.

Description

LTCC miniaturized duplexer

Technical Field

The invention relates to an LTCC (Low temperature Co-fired ceramic) miniaturized duplexer, belonging to the technical field of duplexers.

Background

The duplexer is a microwave device widely used in radio receivers, can realize the combination of two different frequency signals or the division of a single broadband signal into two frequency band signals, has the functions of isolating transmitting and receiving signals and ensuring that both receiving and transmitting can work normally at the same time, and is widely used in the fields of mobile communication, electronic countermeasure and the like. The technical indexes of the duplexer mainly comprise: the working frequency band, in-band insertion loss, in-band return loss, out-of-band rejection, output end isolation and the like, and in addition, the temperature stability, the volume, the weight and the like of the duplexer are important indexes for measuring the performance of the duplexer.

With the high-speed development of wireless communication technology, communication systems develop towards the directions of high performance, high reliability and miniaturization, the size and the weight of a duplexer are required to be small, the working frequency band of the duplexer in the duplexer is required to be wide, the characteristics of the duplexer are good, and the common mode rejection degree is high, but the size of the duplexer in the prior art cannot meet the requirement of wireless communication on the size more and more, a parasitic passband exists in a low-pass duplexer in a traditional duplexer, and the external band rejection capability of a high-pass duplexer cannot meet the requirement of a microwave millimeter wave circuit.

Disclosure of Invention

The invention aims to overcome the defects of the existing duplexer and provides the LTCC miniaturized duplexer, which realizes the effects of restraining the parasitic passband on the low-pass duplexer and optimizing the out-of-band restraint of the high-pass duplexer by reasonable three-dimensional layout and utilizing the parasitic parameters of all elements.

The invention is realized by adopting the following technical scheme:

the utility model provides a miniaturized duplexer of LTCC, including LTCC base member layer, LTCC base member layer forms has duplexer circuit structure, duplexer circuit structure comprises low pass filter circuit and high pass filter circuit, low pass filter circuit is including establishing ties the inductance between common input end and low frequency output port, be connected with the electric capacity of being connected with the ground connection port between two adjacent inductances, high pass filter circuit is including establishing ties the electric capacity between common input end and high frequency output port, be connected with the inductance of being connected with the ground connection port between two adjacent electric capacities.

Furthermore, the low-pass filter circuit comprises a first inductor and a second inductor which are connected in series between the common input end and the low-frequency output port, a first capacitor is connected between the first inductor and the second inductor, and the first capacitor is connected with the ground port.

Furthermore, the high-pass filter circuit comprises a second capacitor, a third capacitor and a fourth capacitor which are connected in series between the common input end and the high-frequency output port, a third inductor is connected between the fourth capacitor and the third capacitor, and a fourth inductor is connected between the third capacitor and the second capacitor.

Furthermore, the first inductor, the second inductor, the third inductor and the fourth inductor are realized by adopting laminated inductors, metal conductors on different circuit layers are connected through holes, and the inductance value is adjusted by adjusting the line length and the line width of each layer of the laminated inductor line.

Furthermore, the first inductor is connected with the common input port through an inductor line of a third layer, the second inductor is connected with the low-frequency output port through an inductor line of a third layer, a connecting line is arranged between the first inductor and the second inductor, a connecting through hole is arranged on the connecting line, the first inductor and the second inductor are connected with a superior plate of the first capacitor through the connecting through hole, a subordinate plate of the first capacitor is connected with the grounding port, a connecting line is arranged between the third inductor and the fourth inductor and connected with the grounding port through the connecting line, a subordinate plate of the second capacitor is connected with the high-frequency output port, the second capacitor and the third capacitor are connected with the third inductor through a through hole, the third capacitor and the fourth capacitor are connected with the fourth inductor through a through hole, and the fourth capacitor is connected with the common input port.

The invention has the beneficial effects that:

according to the invention, through reasonable three-dimensional layout, parasitic pass band suppression on the low-pass duplexer and out-of-band suppression effect optimization of the high-pass duplexer are realized by using parasitic parameters of all elements, balance of the duplexer on volume and performance is realized, low-loss, high-suppression degree and high-isolation effect are realized on the duplexer with small volume, different packaging structures can be designed according to the use scene of the duplexer, and integration with other microwave components is facilitated.

Drawings

Fig. 1 is a circuit diagram of an LTCC miniaturized duplexer;

fig. 2 is an overall structural view of the LTCC miniaturized duplexer;

fig. 3 is a schematic port diagram of an LTCC miniaturized duplexer;

fig. 4 is a schematic circuit isolation diagram of an LTCC miniaturized duplexer;

fig. 5 shows simulation results of S-parameters of the LTCC miniaturized duplexer.

The labels in the figure are: 1. an LTCC substrate layer; 2. a low-pass filter circuit; 3. a high pass filter circuit.

Detailed Description

The invention will be further explained with reference to the drawings.

As shown in fig. 1, in the circuit schematic diagram of the present invention, the duplexer circuit structure is composed of a low-pass filter circuit 2 and a high-pass filter circuit 3, the low-pass filter circuit includes an inductor L1, an inductor L2, and a capacitor C1, wherein the common input terminal P1 is connected to the inductor L1, the other end of the inductor L1 is connected to the inductor L2, and the other end of the inductor L2 is connected to the low-frequency output port P2; a grounding capacitor C1 is connected between the inductor L1 and the inductor L2. The high-pass filter circuit comprises an inductor L3, an inductor L4, a capacitor C2, a capacitor C3 and a capacitor C4, wherein a shared input end P1 is connected with the capacitor C4, the other end of the capacitor C4 is connected with the capacitor C3, the other end of the capacitor C3 is connected with the capacitor C2, and the other end of the capacitor C2 is connected with a high-frequency output port P3; an inductor L3 is connected between the capacitor C4 and the capacitor C3, and an inductor L4 is connected between the capacitor C3 and the capacitor C2.

As shown in fig. 2-3, the invention comprises an LTCC substrate layer 1, wherein a common input terminal, a low frequency output terminal, a high frequency output terminal, a three-terminal ground, a low pass filter circuit 2 and a high pass filter circuit 3 are formed on the LTCC substrate layer 1; the long side of the LTCC substrate is sequentially distributed with a port ground GND1, a common input end P1 and a port ground GND 2; and a low-frequency output port P2, a port ground GND3 and a high-frequency output port P3 are sequentially distributed opposite to the long side of the LTCC substrate.

As shown in fig. 4, the LTCC substrate of the present invention includes nine circuit layers, the first layer, the second layer and the third layer form the first inductor and the second inductor of the low pass filter circuit, the fourth layer and the fifth layer form the first capacitor, the sixth layer and the seventh layer form the third inductor and the fourth inductor of the high pass filter circuit, and the eighth layer and the ninth layer form the second capacitor, the third capacitor and the fourth capacitor of the high pass filter circuit. Specifically, the method comprises the following steps: the inductor (1-L1) and the inductor (1-L2) are printed on the ceramic dielectric, wherein the inductor (1-L1) and the inductor (1-L2) are connected through a connecting wire, a through hole (1-V5) is connected between the inductor (1-L1) and the inductor (1-L2), the other end of the inductor (1-L1) is connected with the inductor (1-V1), and the other end of the inductor (1-L2) is connected with the inductor (1-V2); the second layer is characterized in that an inductor (2-L1) and an inductor (2-L2) are printed on the ceramic dielectric, one end of the inductor (2-L1) is connected with a through hole (1-V1), the other end of the inductor is connected with a through hole (2-V1), one end of the inductor (2-L2) is connected with a through hole (1-V2), the other end of the inductor is connected with a through hole (2-V2), and the through hole (1-V5) is connected with a through hole (2-V5); a third layer, wherein an inductor (3-L1) and an inductor (3-L2) are printed on the ceramic dielectric, one end of the inductor (3-L1) is connected with a through hole (2-V1), the other end of the inductor is connected with a common input end P1, one end of the inductor (3-L2) is connected with a through hole (2-V2), the other end of the inductor is connected with a low-frequency output port P2, and the through hole (2-V5) is connected with a through hole (3-V5); a fourth layer, a capacitor (4-C1) is printed on the ceramic dielectric, and the capacitor (4-C1) is connected with the through hole (3-V5); a fifth layer, a capacitor (5-C1) and a port ground GND3 connecting line are printed on the ceramic dielectric; a sixth layer, wherein an inductor (6-L3) and an inductor (6-L4) are printed on the ceramic dielectric, one end of the inductor (6-L3) is connected with one end of the inductor (6-L4), the connection middle is connected with a port ground GND3 through a connecting wire, the other end of the inductor (6-L3) is connected with a through hole (6-V3), and the other end of the inductor (6-L4) is connected with the through hole (6-V4); a seventh layer, wherein an inductor (7-L3) and an inductor (7-L4) are printed on the ceramic dielectric, one end of the inductor (7-L3) is connected with the through hole (6-V3), the other end of the inductor is connected with the through hole (7-V6), one end of the inductor (7-L4) is connected with the through hole (6-V4), and the other end of the inductor is connected with the through hole (7-V7); an eighth layer, wherein a capacitor (8-C2), a capacitor (8-C3) and a capacitor (8-C4) are printed on the ceramic dielectric, the capacitor (8-C2) is connected with the high-frequency output port P3 through a connecting line, the capacitor (8-C3) is connected with the capacitor (8-C4) through the connecting line, and a through hole (7-V6) is connected with the connecting line of the capacitor (8-C3) and the capacitor (8-C4); and a ninth layer, wherein a capacitor (9-C2), a capacitor (9-C3) and a capacitor (9-C4) are printed on the ceramic dielectric, the capacitor (9-C2) and the capacitor (9-C3) are connected through a connecting line, a connecting line between the capacitor (9-C2) and the capacitor (9-C3) is connected with a through hole (8-V6), and the capacitor (9-C4) is connected with a common input terminal P1 through the connecting line.

As shown in FIG. 5, in one embodiment of the present invention, the low frequency operating frequency is DC-3.0 GHz, and the high frequency operating frequency is 4.0 GHz-6.5 GHz, which can be used for Wi-Fi communication applications. The insertion loss of the duplexer in two wave bands is better than 0.8dB, the return loss in the two wave bands is better than 15dB, the isolation is better than 20dB, the out-of-band rejection is better than 20dB, and the packaging size is only (2.0mm multiplied by 1.25mm multiplied by 0.59 mm).

The foregoing shows and describes the general principles and broad features of the present invention and advantages thereof. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims

1. The utility model provides a miniaturized duplexer of LTCC, its characterized in that, includes LTCC base member layer, LTCC base member layer is formed with duplexer circuit structure, duplexer circuit structure comprises low pass filter circuit and high pass filter circuit, low pass filter circuit is connected with the electric capacity of being connected with the ground connection port including establishing ties the inductance between sharing input port and low frequency output port between two adjacent inductances, high pass filter circuit is connected with the inductance of being connected with the ground connection port including establishing ties the electric capacity between sharing input end and high frequency output port between two adjacent capacitances.

2. The LTCC miniaturized duplexer of claim 1, wherein: the low-pass filter circuit comprises a first inductor and a second inductor which are connected in series between the common input port and the low-frequency output port, a first capacitor is connected between the first inductor and the second inductor, and the first capacitor is connected with the grounding port.

3. The LTCC miniaturized duplexer of claim 1, wherein: the high-pass filter circuit comprises a second capacitor, a third capacitor and a fourth capacitor which are connected in series between the common input port and the high-frequency output port, a third inductor is connected between the fourth capacitor and the third capacitor, and a fourth inductor is connected between the third capacitor and the second capacitor.

4. The LTCC miniaturized duplexer of claim 2 or 3, wherein: the first inductor, the second inductor, the third inductor and the fourth inductor are realized by adopting laminated inductors, metal conductors on different circuit layers are connected through holes, and the inductance value is adjusted by adjusting the line length and the line width of each layer of the laminated inductor line.

5. The LTCC miniature duplexer according to claim 4, wherein the first inductor is connected to the common input port through an inductor of a third layer, the second inductor is connected to the low frequency output port through an inductor of a third layer, a connecting wire is arranged between the first inductor and the second inductor, a connecting through hole is arranged on the connecting wire, the first inductor and the second inductor are connected to a higher-level board of the first capacitor through the connecting through hole, a lower-level board of the first capacitor is connected to the ground port, a connecting wire is arranged between the third inductor and the fourth inductor and connected to the ground port through the connecting wire, a lower-level board of the second capacitor is connected to the high frequency output port, the second capacitor and the third capacitor are connected to the third inductor through a through hole, the third capacitor and the fourth capacitor are connected to the fourth inductor through a through hole, and the fourth capacitor is connected to the common input port.