Murata Manufacturing has filed a patent for a composite filter device that includes a ladder filter and at least one bandpass filter. The device features a specific arrangement of serial and parallel arm resonators, with the first serial arm resonator and first parallel arm resonator being closest to the common terminal. The patent claims that certain expressions involving the duty of the IDT electrodes of the resonators are satisfied. GlobalData’s report on Murata Manufacturing gives a 360-degree view of the company including its patenting strategy. Buy the report here.
Smarter leaders trust GlobalData
According to GlobalData’s company profile on Murata Manufacturing, Battery management systems was a key innovation area identified from patents. Murata Manufacturing's grant share as of September 2023 was 42%. Grant share is based on the ratio of number of grants to total number of patents.
Composite filter device with ladder filter and bandpass filter
A recently filed patent (Publication Number: US20230318571A1) describes a composite filter device that includes a ladder filter and at least one bandpass filter. The ladder filter consists of a serial arm resonator and a parallel arm resonator, both of which are acoustic wave resonators with IDT electrodes. The first serial arm resonator and the first parallel arm resonator are closest to the common terminal of the ladder filter. The device satisfies one of three expressions involving the duty of the IDT electrodes of the resonators.
In one embodiment of the invention, the first serial arm resonator and the first parallel arm resonator each include a piezoelectric layer with an IDT electrode, and the piezoelectric layer is made of LiTaO3 substrate.
Another embodiment includes a high acoustic-velocity body laminated on the opposite surface of the piezoelectric layer from the IDT electrode. This high acoustic-velocity body is made of a material that allows bulk waves to propagate at a higher velocity than the acoustic waves propagating through the piezoelectric layer. Additionally, a low acoustic-velocity layer is included between the high acoustic-velocity body and the piezoelectric layer, allowing bulk waves to propagate at a lower velocity than the piezoelectric layer.
The composite filter device can have multiple serial arm resonators and parallel arm resonators, with a size relationship between duties that is opposite to the size relationship between wavelengths determined by the electrode finger pitch.
The common terminal of the device can be connected to an antenna terminal. The ladder filter can include five serial arm resonators connected in series, and four parallel arm resonators connected between a ground potential and the serial arm resonators.
The device can also include two bandpass filters, each of which can be a ladder filter or a bandpass filter with a longitudinally-coupled resonator acoustic wave filter. The passband of the bandpass filter can be different from the passband of the ladder filter.
The acoustic wave resonator in the device includes reflectors on opposite sides of the IDT electrode and can be a one-port acoustic wave resonator.
The piezoelectric layer in the device can be a composite piezoelectric substrate with a low acoustic velocity layer and a piezoelectric layer. The thickness of the piezoelectric layer can be about 10? or lower, where ? is the wavelength determined by the electrode finger pitch.
In one embodiment, the duty of the first serial arm resonator is about 0.425 to about 0.5.
To know more about GlobalData’s detailed insights on Murata Manufacturing, buy the report here.
Data Insights
From
The gold standard of business intelligence.
Blending expert knowledge with cutting-edge technology, GlobalData’s unrivalled proprietary data will enable you to decode what’s happening in your market. You can make better informed decisions and gain a future-proof advantage over your competitors.
GlobalData, the leading provider of industry intelligence, provided the underlying data, research, and analysis used to produce this article.
GlobalData Patent Analytics tracks bibliographic data, legal events data, point in time patent ownerships, and backward and forward citations from global patenting offices. Textual analysis and official patent classifications are used to group patents into key thematic areas and link them to specific companies across the world’s largest industries.
