CN-114257210-B - Elastic wave device

Abstract

An elastic wave device includes a substrate, a first transmission filter provided on a first main surface of the substrate and having a transmission band of a first frequency band in frequency division duplex as a pass band, a first reception filter provided on the first main surface of the substrate and having a reception band of the first frequency band in frequency division duplex as a pass band, a second transmission filter provided on the first main surface of the substrate and having a transmission band of a second frequency band in frequency division duplex as a pass band, a second reception filter provided on the first main surface of the substrate and having a reception band of the second frequency band in frequency division duplex as a pass band, and a first antenna terminal provided on the second main surface of the substrate, wherein the first transmission filter is provided at a position closer to the first antenna terminal than the second transmission filter, and the first reception filter is provided at a position closer to the first antenna terminal than the second reception filter. Thereby ensuring isolation between bands to reduce loss.

Inventors

• KUWABARA HIDESHI
• Oka Yasuhira

Assignees

• 三安日本科技株式会社

Dates

Publication Date

20260508

Application Date

20210615

Priority Date

20200921

Claims (8)

1. 1. An elastic wave device, characterized in that: The elastic wave device includes a substrate, a first transmission filter disposed on a first main surface of the substrate by flip-chip bonding and having a transmission band of a first frequency band in frequency division duplex as a pass band, a first reception filter disposed on the first main surface of the substrate by flip-chip bonding and having a reception band of the first frequency band in frequency division duplex as a pass band, a second transmission filter disposed on the first main surface of the substrate by flip-chip bonding and having a transmission band of a second frequency band in frequency division duplex as a pass band, a second reception filter disposed on the first main surface of the substrate by flip-chip bonding and having a reception band of the second frequency band in frequency division duplex as a pass band, and first antenna terminals and second antenna terminals disposed on the second main surface of the substrate, and first wirings of the first reception filters, and second wirings electrically connecting the first antenna terminals, the first transmission filters, and the second wirings penetrating the second main surface of the substrate without crossing the second main surface; The first transmission filter is disposed closer to the first antenna terminal than the second transmission filter, and the first reception filter is disposed closer to the first antenna terminal than the second reception filter.
2. 2. The elastic wave device according to claim 1, wherein: the second main surface of the substrate is further provided with an input terminal of the first transmission filter, an output terminal of the first reception filter, an input terminal of the second transmission filter, an output terminal of the second reception filter, and a ground terminal.
3. 3. The elastic wave device according to claim 1, wherein: The antenna further includes a metal pattern disposed on the second main surface of the substrate and located between the first antenna terminal and the second antenna terminal.
4. 4. The elastic wave device according to claim 1, wherein: the first transmit filter is configured to abut the second transmit filter and the first receive filter is configured to abut the second receive filter.
5. 5. The elastic wave device according to claim 1, wherein: at least one of the first transmission filter, the second transmission filter, the first reception filter, and the second reception filter is a surface acoustic wave filter.
6. 6. The elastic wave device according to claim 5, wherein: the surface acoustic wave filter has a piezoelectric substrate bonded to a support substrate made of high-impedance silicon, gallium arsenide, sapphire, spinel, polycrystalline alumina, or glass.
7. 7. The elastic wave device according to claim 1, wherein: At least one of the first transmission filter, the second transmission filter, the first reception filter, and the second reception filter is a filter using a piezoelectric thin film resonator.
8. 8. The elastic wave device according to claim 7, wherein: The piezoelectric thin film resonator includes a chip substrate, a piezoelectric film provided on the chip substrate, a lower electrode, and an upper electrode, wherein the piezoelectric film is sandwiched between the lower electrode and the upper electrode, and a gap is formed between the lower electrode and the chip substrate.

Description

Elastic wave device Technical Field The present invention relates to an elastic wave device, for example, a double duplexer including a plurality of elastic wave filters. Background In a device such as a smart phone as a mobile communication terminal, communication in a plurality of corresponding frequency bands is required. Therefore, an elastic wave device including a plurality of elastic wave filters, a plurality of diplexers, a quad-filter, or the like is used. In addition, in the elastic wave device, it is necessary to consider interference between the transmission filter and the reception filter, and low loss is required. As described in patent document 1 (japanese patent application laid-open No. 2019-54354), four filters are designed to be provided at appropriate positions in consideration of interference between a plurality of filters. Disclosure of Invention The main problems to be solved by the present invention are described below. In the case of forming an elastic wave device having a double duplexer function by providing four elastic wave filters on a substrate, a loss is caused by interference between a transmission filter and a reception filter. Furthermore, the inability to fully isolate bands can also result in loss. The present invention has been made in view of the above-described problems, and an object thereof is to provide an elastic wave device capable of suppressing interference between a transmission filter and a reception filter, ensuring isolation between frequency bands, and reducing loss. The elastic wave device includes a substrate, a first transmission filter provided on a first main surface of the substrate and having a transmission band of a first frequency band in frequency division duplex as a pass band, a first reception filter provided on the first main surface of the substrate and having a reception band of the first frequency band in frequency division duplex as a pass band, a second transmission filter provided on the first main surface of the substrate and having a transmission band of a second frequency band in frequency division duplex as a pass band, a second reception filter provided on the first main surface of the substrate and having a reception band of the second frequency band in frequency division duplex as a pass band, and a first antenna terminal provided on the second main surface of the substrate, wherein the first transmission filter is provided closer to the first antenna terminal than the second transmission filter, and the first reception filter is provided closer to the first antenna terminal than the second reception filter. In one aspect of the present invention, the second main surface of the substrate is further provided with a second antenna terminal. In one aspect of the present invention, the elastic wave device further includes a first wire electrically connected to the first antenna terminal, the first transmission filter, and the first reception filter, and a second wire electrically connected to the second antenna terminal, the second transmission filter, and the second reception filter, wherein the first wire and the second wire do not intersect each other stereoscopically. In one aspect of the present invention, the elastic wave device further includes an input terminal of the first transmission filter, an output terminal of the first reception filter, an input terminal of the second transmission filter, an output terminal of the second reception filter, and a ground terminal on the second main surface of the substrate. In one aspect of the present invention, the elastic wave device further includes a metal pattern provided on the second main surface of the substrate and located between the first antenna terminal and the second antenna terminal. In one aspect of the present invention, the first transmission filter is disposed adjacent to the second transmission filter, and the first reception filter is disposed adjacent to the second reception filter. In one aspect of the present invention, at least one of the first transmission filter, the second transmission filter, the first reception filter, and the second reception filter is a surface acoustic wave filter. In one embodiment of the present invention, the surface acoustic wave filter includes a piezoelectric substrate bonded to a support substrate made of high-impedance silicon, gallium arsenide, sapphire, spinel, polycrystalline alumina, or glass. In one aspect of the present invention, at least one of the first transmission filter, the second transmission filter, the first reception filter, and the second reception filter is a filter using a piezoelectric thin film resonator. In one aspect of the present invention, the piezoelectric thin film resonator includes a chip substrate, a piezoelectric film provided on the chip substrate, a lower electrode, and an upper electrode, wherein the piezoelectric film is sandwiched between the lower electrode and the upper electrode, and a gap