GB2615395A

GB2615395A - LTCC (low temperature co-fired ceramic) miniaturized duplexer

Info

Publication number: GB2615395A
Application number: GB2218140.8A
Authority: GB
Inventors: Yang Chengtao; Xing Mengjiang; Dai Chuanxiang; Yang Xiaodong; Xing Mengdao; Liu Yonghong
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: 2022-12-02
Publication date: 2023-08-09
Also published as: GB202218140D0; CN114362707A

Abstract

An LTCC miniaturized duplexer comprises an LTCC base body layer 1. A duplexer circuit structure is formed on the LTCC base body layer. 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 comprises inductors L1, L2 connected in series between a common input port P1 and a low-frequency output port P2. A capacitor C1 connected with a grounding port is connected between every two adjacent inductors L1, L2. The high-pass filter circuit 3 comprises capacitors C2, C3, C4 connected in series between the common input end P1 and a high-frequency output port P3. An inductor L3, L4 connected with the grounding port is connected between every two adjacent capacitors C2, C3, C4. The effects of suppressing a parasitic passband on the low-pass duplexer and optimizing out-of-band rejection of the high-pass duplexer are achieved by using the parasitic parameters of all components through reasonable three-dimensional layout.

Description

LTCC (LOW TEMPERATURE CO-FIRED CERAMIC) MINIATURIZED DUPLEXER

TECHNICAL FIELD

[0001] The present disclosure relates to an LTCC (Low Temperature Co-fired Ceramic) miniaturized duplexer, and belongs to the technical field of duplexers.

BACKGROUND

[0002] The diplexer is a microwave device widely used in radio receivers. Two pilot-frequency signals can be combined or a single broadband signal can be divided into two frequency-band signals. The transmitting and receiving signals are isolated to ensure that both receiving and transmitting can work normally at the same time. The diplexer is widely used in mobile communication, electronic countermeasures and other fields. The duplexer has the technical indexes of working frequency band, in-band insertion loss, in-band return loss, out-of-band suppression, output end isolation and the like. In addition, the temperature stability, volume and weight of the duplexer are also important indexes to measure the performances.

[0003] With the rapid development of wireless communication technology, the communication system is developed in the aspects of high performance, high reliability and miniaturization. The diplexer is required to be small in size and light in weight, and the diplexer is required to be wide in working frequency, good in characteristics and in high common-mode rejection. However, the volume of the diplexer in the prior art is increasingly unable to meet the volume requirement of wireless communication, and the parasitic passband exists in the low-pass diplexer in the traditional diplexer, so that the out-band rejection capability of the high-pass diplexer cannot meet the requirements of microwave and millimeter-wave circuits.

SUMMARY

[0004] The present disclosure aims to overcome the above-mentioned defects existing in the existing duplexers, and provides an LTCC miniaturized duplexer. The effects of suppressing a parasitic passband on the low-pass duplexer and optimizing out-of-band rejection of the high-pass duplexer are achieved by using the parasitic parameters of all components through reasonable three-dimensional layout.

[0005] The present disclosure is achieved by the following technical schemes.

[0006] An LTCC miniaturized duplexer comprises an LTCC base body layer, wherein a duplexer circuit structure is formed on the LTCC base body layer, the duplexer circuit structure is composed of a low-pass filter circuit and a high-pass filter circuit, 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 grounding port is connected between every two adjacent inductors, the high-pass filter circuit comprises capacitors connected in series between a common input end and a high-frequency output port, and an inductor connected with the grounding port is connected between every two adjacent capacitors.

[0007] Further, the low-pass filter circuit comprises a first inductor and a second inductor 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.

[0008] Further, the high-pass filter circuit comprises a second capacitor, a third capacitor and a fourth capacitor 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.

[0009] Further, the first inductor, the second inductor, the third inductor and the fourth inductor are realized by laminated inductors, metal conductors on different circuit layers are connected through through holes, and the inductance valuc is adjusted by adjusting the wire length and wire width of each layer of laminated inductor wires.

[0010] Further, the first inductor is connected with the common input port through the third layer of inductor wires, the second inductor is connected with the low-frequency output port through the third layer of inductor wires, a connecting wire is arranged between the first inductor and the second inductor, a connecting through hole is formed in the connecting wire, the first inductor and the second inductor are connected with the upper plate of the first capacitor through the connecting through hole, the lower plate of the first capacitor is connected with the grounding port, a connecting wire is arranged between die third inductor and the fourth inductor, the connecting wire is connected with the grounding port, the lower 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 the through hole, the third capacitor and the fourth capacitor are connected with the fourth inductor through the through hole, and the fourth capacitor is connected with the common input port.

[0011] The present disclosure has the following beneficial effects.

[0012] The effects of suppressing a parasitic passband on the low-pass duplexer and optimizing out-of-band rejection of the high-pass duplexer are achieved by using the parasitic parameters of all components through reasonable three-dimensional layout. The balance between volume and performance of the duplexer is achieved, the effects of low loss, high suppression and high isolation are achieved on the small-volume duplexer, and different packaging structures can be designed according to the usage scenarios of the duplexer, so that the LTCC miniaturized duplexer is convenient for integration with other microwave components.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] FIG. I is a circuit diagram of an LTCC miniaturized duplexer.

[0014] FIG. 2 is an integral structure chart of an LTCC miniaturized duplexer.

[0015] FIG. 3 is a port schematic diagram of an LTCC miniaturized duplexer.

[0016] FIG. 4 is a circuit separated schematic diagram of an LTCC miniaturized duplexer.

[0017] FIG. 5 is an S-parameter simulation result of an LTCC miniaturized duplexer.

[0018] Reference signs: 1, LTCC base body layer; 2, low-pass filter circuit; and 3, high-pass filter circuit.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] The present disclosure is further described below in combination with the attached figures. [0020] FIG. 1 is a circuit diagram of an LTCC miniaturized duplexer. 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 comprises an inductor Li, an inductor L2 and a capacitor Cl, wherein a common input end PI is connected with the inductor LI, the other end of the inductor LI is connected with the inductor L2, and the other end of the inductor L2 is connected with a low-frequency output port P2. The grounding capacitor Cl is connected between the inductor L I 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 the common input end PI is connected with the capacitor 4, 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. The inductor L3 is connected between the capacitor C4 and the capacitor C3, and the inductor L4 is connected between the capacitor C3 and the capacitor C2.

[0021] As shown in FIG. 2 and FIG. 3, the LTCC miniaturized duplexer comprises an LTCC base body layer 1. The LTCC base body layer 1 is provided with the common input end, the low-frequency output port, the high-frequency output port, three port grounds, the low-pass filter circuit 2 and the high-pass filter circuit 3. The port ground GND1, the common input end P1 and the port ground GND2 are sequentially distributed on the long side of the LTCC base body. The low-frequency output port P2, the port ground GND3 and the high-frequency output port P3 are sequentially disbibuted on the opposite of the long side of the LTCC base body.

[0022] As shown in FIG. 4, the LTCC base body is internally provided with nine circuit layers. The first layer, the second layer and the third layer are provided with the first inductor and the second inductor with the low-pass filter circuit. The fourth layer and the fifth layer are provided with the first capacitor. The sixth layer and the seventh layer are provided with the third inductor and the fourth inductor with the high-pass filter circuit. The eight layer and the ninth layer are provided with the second capacitor, the third capacitor and the fourth capacitor with the high-pass filter circuit. Specifically, on the first layer, the inductor (1-L1) and the inductor (1-L2) are printed on the ceramic medium, wherein the inductor (1-LI) and the inductor (1-L2) are connected by the connecting wire, the through hole (1-V5) is connected between the inductor (1-L1) and the inductor (1-L2), the other end of the inductor (1 -L 1) is connected with the through hole (1-V1), and the other end of the inductor (1-L2) is connected with the through hole (1-V2). On the second layer, the inductor a-L1) and the inductor (2-L2) are printed on the ceramic medium, one end of the inductor (2-LI) is connected with the through hole (1-V1), the other end is connected with the through hole (2-V1), one end of the inductor (2-L2) is connected with the through hole (1-V2), the other end of the inductor (2-L2) is connected with the through hole (2-V2), and the through hole (1-V5) is connected with the through hole (2-V5). On the third layer, the inductor (3-L1) and the inductor (3-L2) are printed on the ceramic medium, one end of the inductor (3-L1) is connected with the through hole (2-V1), the other end of the inductor (3-L1) is connected with the common input end Pl, one end of the inductor (3-L2) is connected with the through hole (2-V2), the other end of the inductor (3-L2) is connected with the low-frequency output port P2, and the through hole (2-V5) is connected with the through hole (3-V5). On the fourth layer, the capacitor (4-C1) is printed on the ceramic medium, and the capacitor (4-C1) is connected with the through hole (3V5). On the fifth layer, the capacitor (5-C1) and the port ground GND3 connecting wire are printed on the ceramic medium. On the sixth layer, the inductor (6-L3) and the inductor (6-L4) are printed on the ceramic medium, one end of the inductor (6-L3) is connected with one end of the inductor (6-LA), the connecting wire is connected with the port ground GND3, the other end of the inductor (6-L3) is connected with the through hole (6-V3), and the other end of the inductor (6-L4) is connected with the through hole (6-V4). On the seventh layer, the inductor (7-L3) and the inductor (7-L4) are printed on the ceramic medium, one end of the inductor (7-L3) is connected with the through hole (6-V3), the other end of the inductor (7-L3) is connected with the through hole (7V6), one end of the inductor (7-L4) is connected with the through hole (6-V4), and the other end of the inductor (7-L4) is connected with the through hole (7-V7). On the eighth layer, the capacitor (8-C2), the capacitor (8-C3) and the capacitor (8-C4) are printed on the ceramic medium, the capacitor (8-C2) is connected with the high-frequency output port P3 through the connecting wire, the capacitor (8-C3) and capacitor (8-C4) are connected through the connecting wire, and the connecting wire of the capacitor (8-C3) and the capacitor (8-C4) is connected with the through hole (7-V6). On the ninth layer, the capacitor (9-C2), the capacitor (9-C3) and the capacitor (9-C4) are printed on the ceramic media, the capacitor (9-C2) and the capacitor (9-C3) are connected through the connecting wire, the connecting wire of the capacitor (9-C2) and the capacitor (9-C3) is connected with the through hole (8-V6), and the capacitor (9-C4) is connected with the common input port PI through the connecting wire.

I00231 As shown in FIG. 5, in one embodiment of the present disclosure, the low-frequency working frequency is DC to 3.0 GHz, the high-frequency working frequency is 4.0 GHz to 6.5 GHz, and the LTCC miniaturized duplexer can be applied to Wi-Fi communication application. The insertion loss in both bands of the duplexer is superior to 0.8dB, the return loss in both bands of the duplexer is superior to 15dB, the isolation is superior to 20dB, the out-of-band rejection is superior to 20dB, and the package size is only (2.0mm x 1.25mm x 0.59mm) [0024] The basic principles, principal features and advantages of the present disclosure are shown and described above. Those skilled in the art should understand that the present disclosure is not limited by the above-described embodiments, the above-described embodiments and specification are merely illustrative of the principles of the present disclosure, various changes and modifications may occur to the present disclosure under the premise of without departing from the spirit and scope of the present disclosure, and these changes and modifications fall within the scope of the present disclosure as claimed. The scope of the present disclosure is defined by the appended claims and equivalents thereof

Claims

CLAIMS1. An LTCC (Low Temperature Co-fired Ceramic) miniaturized duplexer. comprising an LTCC base body layer, wherein a duplexer circuit structure is formed on the LTCC base body layer, the duplexer circuit structure is composed of a low-pass filter circuit and a high-pass filter circuit, 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 grounding port is connected between every two adjacent inductors, the high-pass filter circuit comprises capacitors connected in series between a common input end and a high-frequency output port, and an inductor connected with the grounding port is connected between every two adjacent capacitors.
2. The LTCC miniaturized duplexer according to claim I, wherein the low-pass filter circuit comprises a first inductor and a second inductor 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 according to claim 1, wherein the high-pass filter circuit comprises a second capacitor, a third capacitor and a fourth capacitor 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 according to claim 2 or 3, wherein the first inductor, the second inductor, the third inductor and the fourth inductor are realized by laminated inductors, metal conductors on different circuit layers are connected through through holes, and the inductance value is adjusted by adjusting the wire length and wire width of each layer oflaminated inductor wires.
5. The LTCC miniaturized duplexer according to claim 4, wherein the first inductor is connected with the common input port through the third layer of inductor wires, the second inductor is connected with the low-frequency output port through the third layer of inductor wires, a connecting wire is arranged between the first inductor and the second inductor, a connecting through hole is formed in the connecting wire, the first inductor and the second inductor are connected with the upper plate of the first capacitor through the connecting through hole, the lower plate of the first capacitor is connected with the grounding port, a connecting wire is arranged between the third inductor and the fourth inductor, the connecting wire is connected with the grounding port, the lower 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 the through hole, the third capacitor and the fourth capacitor are connected with the fourth inductor through the through hole, and the fourth capacitor is connected with the common input port.