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CN-122003812-A - Multiplexer for multiplexing

CN122003812ACN 122003812 ACN122003812 ACN 122003812ACN-122003812-A

Abstract

A multiplexer is disclosed that includes a first band pass filter connected to an antenna to allow signals of a low frequency band to pass therethrough, and a second band pass filter connected to the antenna to allow signals of a high frequency band to pass therethrough. The first band pass filter is formed of a Surface Acoustic Wave (SAW) resonator included in the bare chip, and the second band pass filter is formed of an inductor included in the package and a capacitor included in the bare chip.

Inventors

  • Jin Hengkun
  • He Dingdao
  • JIANG SHENGJUN
  • ZHANG XUN

Assignees

  • 天津威盛电子有限公司

Dates

Publication Date
20260508
Application Date
20240730
Priority Date
20230801

Claims (7)

  1. 1. A multiplexer, comprising: a first band-pass filter connected to the antenna to allow the low-band signals to pass therethrough, and A second band pass filter connected to the antenna to allow a signal of a high frequency band to pass therethrough, Wherein the first band-pass filter is formed of a Surface Acoustic Wave (SAW) resonator included in a bare chip, and Wherein the second band pass filter is formed of an inductor included in a package and is formed as a capacitor included in the bare chip.
  2. 2. The multiplexer of claim 1, wherein the capacitor comprises at least one of an interdigital transducer (IDT) capacitor and a metal-insulator-metal (MIM) capacitor.
  3. 3. The multiplexer of claim 1 wherein the IDT capacitor is arranged to be rotated 90 degrees relative to an IDT forming the SAW resonator.
  4. 4. The multiplexer of claim 1 wherein the IDT capacitor has a thickness that is at least 1.5 times the thickness of an IDT forming the SAW resonator.
  5. 5. The multiplexer of claim 2 wherein the IDT capacitor has a linewidth at least 1.5 times the linewidth of the IDT forming the SAW resonator.
  6. 6. The multiplexer of claim 2, wherein a spacing between adjacent lines of the IDT capacitor is 30% or less of a line width of the IDT capacitor.
  7. 7. The multiplexer of claim 2, wherein the MIM capacitor comprises a main metal layer and a subsidiary metal layer formed of the same material as the first band-pass filter included in the die.

Description

Multiplexer for multiplexing Technical Field The present disclosure relates to a multiplexer, and more particularly, to a multiplexer including a plurality of filters connected to an antenna and allowing signals in different frequency bands to pass therethrough, respectively. Background There is a trend for mobile communication terminals to support multi-band and multi-mode communication, and thus, a multiplexer is essential for a Radio Frequency (RF) front-end module. Typically, the multiplexer comprises a plurality of filters connected to the antenna and allowing signals in different frequency bands to pass through, respectively. The plurality of filters may include a low pass filter, a band pass filter, and a high pass filter. However, the conventional multiplexer implements a high frequency filter using capacitor elements and inductor elements within the package, and also implements a low frequency filter using an interdigital transducer (IDT) within the chip, which causes parasitic coupling to occur due to the close proximity of the capacitors and inductors within the package. Disclosure of Invention The present disclosure provides a multiplexer that can increase space utilization within a multiplexer package and reduce mutual parasitic coupling. In one general aspect, a multiplexer includes a first band pass filter connected to an antenna to allow signals of a low frequency band to pass therethrough, and a second band pass filter connected to the antenna to allow signals of a high frequency band to pass therethrough. The first band pass filter is formed of a Surface Acoustic Wave (SAW) resonator included in the bare chip, and the second band pass filter is formed of an inductor included in the package and is formed as a capacitor included in the bare chip. The capacitor may include at least one of an interdigital transducer (IDT) capacitor and a metal-insulator-metal (MIM) capacitor. The IDT capacitor may be arranged to be rotated 90 ° with respect to the IDT forming the SAW resonator. The IDT capacitor can have a thickness at least 1.5 times the thickness of the IDT forming the SAW resonator. The IDT capacitor can have a linewidth at least 1.5 times the linewidth of the IDT of the SAW resonator. The interval between adjacent lines of the IDT capacitor may be 30% or less of the line width of the IDT capacitor. The MIM capacitor may include a main metal layer and a subsidiary metal layer formed of the same material as the first band-pass filter included in the bare chip. ADVANTAGEOUS EFFECTS OF INVENTION According to the present disclosure described above, the implementation of the capacitor within the die in the high-band pass filter improves the Q factor and reduces the insertion loss. In addition, by placing the IDT capacitor or MIM capacitor within a bare chip instead of within a package to implement a high-band pass filter, space utilization within the package may be increased. Further, parasitic coupling between LC elements caused by capacitors and inductors placed together within the package may be reduced. Drawings Fig. 1 is a circuit diagram of a multiplexer according to one embodiment of the present disclosure. Fig. 2 is a reference diagram of an embodiment in which a first band pass filter and a second band pass filter are implemented in a package and a bare chip. Fig. 3 is a plan enlarged view of an interdigital transducer (IDT) capacitor of a second bandpass filter included in a bare chip. Fig. 4 is a reference diagram of another embodiment in which a first band pass filter and a second band pass filter are implemented in a package and a bare chip. Fig. 5 is a plan view enlarged of a metal-insulator-metal (MIM) capacitor of a second bandpass filter included in a bare chip. Fig. 6 is a graph for evaluating the performance of a first band pass filter and a second band pass filter according to the present disclosure. Detailed Description Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the following description and drawings, substantially the same components are denoted by the same symbols, and redundant description is omitted. Further, in explaining the present disclosure, if it is determined that a specific description of related known functions or configurations would unnecessarily obscure the gist of the present disclosure, a detailed description thereof will be omitted. Fig. 1 is a circuit diagram of a multiplexer 100 according to one embodiment of the present disclosure. The multiplexer 100 according to one embodiment of the present disclosure includes a plurality of filters connected to an antenna and allowing signals in different frequency bands to pass through, respectively. The multiplexer 100 is configured to have a plurality of outputs when the antenna side is an input, and to have a plurality of inputs when the antenna 100 side is an output. Referring to fig. 1, a multiplexer 100 according to the presen