# US 12,184,257 B2 · Hybrid signal filter > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,184,257 B2 - Document ID: US12184257B2 - Status: Granted - Kind: B2 - Application number: 17/689,256 - Filed: 2022-03-08 - Published: 2022-09-15 - Granted: 2024-12-31 - Earliest claimed: 2021-03-10 - Assignees: Tai-Saw Technology Co., Ltd. - Applicants: TAI-SAW Technology Co., Ltd. - Inventors: Shih-Meng Lin; Fu-Kuo Yu; Chih-Chung Hsiao - Web page: https://patentgrep.com/patent/US12184257B2 ## CPC - H03H 7/0115: {comprising only inductors and capacitors (H03H7/075, H03H7/09, H03H7/12, H03H7/13 take precedence)} - H03H 7/075: Ladder networks, e.g. electric wave filters - H03H 7/38: Impedance-matching networks - H03H 9/6409: {SAW notch filters} - H03H 9/6483: {Ladder SAW filters} - H03H 2007/013: {Notch or bandstop filters} - H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P) ## Abstract A signal filter includes a notch filter and a wideband filter. The notch filter is configured to perform a band-rejection filtering operation according to a band-rejection filtering property. The wideband filter is coupled to the notch filter, and is configured to perform a wideband filtering operation according to a wideband filtering property. The band-rejection filtering property includes a first cutoff frequency, a frequency bandwidth, a relatively high quality factor and a relatively low coupling coefficient. The wideband filtering property includes a second cutoff frequency, a relatively low quality factor and a relatively high coupling coefficient. The first and the second cutoff frequencies have a frequency difference therebetween. A ratio of the frequency difference to the frequency bandwidth is within a preset ratio range being from 2.5% to 20%. ## Claims ### Claim 1 A signal filter comprising: a substrate; a notch filter disposed on the substrate and configured to perform a band-rejection filtering operation according to a band-rejection filtering property; a wideband filter disposed on the substrate and configured to perform a wideband filtering operation according to a wideband filtering property; and an impedance matching element, wherein: the substrate supports the notch filter and the wideband filter, and includes a coupling circuit wherein the wideband filter is a bandpass filter; the impedance matching element is electrically coupled to the notch filter and the wideband filter through the coupling circuit; the notch filter is electrically coupled to the wideband filter through the coupling circuit; the band-rejection filtering property includes a first cutoff frequency and a first frequency bandwidth; the wideband filtering property includes a second cutoff frequency; the first and the second cutoff frequencies have a frequency difference therebetween; and a ratio of the frequency difference to the first frequency bandwidth is within a preset ratio range being from 2.5% to 20%. ### Claim 2 (depends on 1) The signal filter according to claim 1, wherein: the substrate is an integrated multilayer substrate; the notch filter disposed on the integrated multilayer substrate; and the wideband filter disposed in the integrated multilayer substrate. ### Claim 3 (depends on 2) The signal filter according to claim 2, wherein: the coupling circuit includes a first outer connection terminal, a second outer connection terminal and an inner connection terminal; the notch filter and the impedance matching element are electrically connected to the first and the second outer connection terminals respectively; and the wideband filter is electrically connected to the inner connection terminal. ### Claim 4 (depends on 1) The signal filter according to claim 1, wherein: the substrate is a printed circuit board; the coupling circuit is a printed circuit; and each of the notch filter and the wideband filter is disposed on the printed circuit board. ### Claim 5 (depends on 4) The signal filter according to claim 4, wherein: the signal filter further comprises an impedance matching unit; the printed circuit includes a first connection terminal, a second connection terminal and a third connection terminal; the notch filter, the impedance matching unit and the wideband filter are electrically connected to the first, the second and the third connection terminals respectively; and the impedance matching unit includes at least one impedance matching element, and is electrically coupled to the notch filter and the wideband filter through the printed circuit. ### Claim 6 (depends on 1) The signal filter according to claim 1, wherein: the band-rejection filtering property includes a relatively high quality factor and a relatively low coupling coefficient; the relatively high quality factor ranges from 950 to 3500; and a shape factor associated with the first frequency bandwidth is within a preset shape factor range being from 0.4 to 0.8. ### Claim 7 (depends on 1) The signal filter according to claim 1, wherein: the wideband filter is one selected from a group consisting of a high-pass filter, a band-pass filter and a low-pass filter; under a condition that the wideband filter is the band-pass filter, the wideband filtering property further includes a second frequency bandwidth and a center frequency; and a ratio of the second frequency bandwidth to the center frequency ranges from 5% to 50%. ### Claim 8 (depends on 7) The signal filter according to claim 7, wherein: the wideband filter is manufactured by using one of a multilayer ceramic capacitor (MLCC) process and a low-temperature co-fired ceramic (LTCC) process in order to meet the wideband filtering property; the wideband filtering property includes a relatively low quality factor and a relatively high coupling coefficient; a coupling ratio associated with the relatively high coupling coefficient ranges from 30% to 60%. ### Claim 9 A signal filter comprising: a first filtering unit configured to perform a first specific filtering operation according to a first specific filtering property; a second filtering unit configured to perform a second specific filtering operation according to a second specific filtering property including a relatively low quality factor and a relatively high coupling coefficient; and a substrate supporting the first and the second filtering units, and including a coupling circuit, wherein the first filtering unit is electrically coupled to the second filtering unit through the coupling circuit, wherein: the first filter unit is a notch filter, and the second filter unit is a wideband filter the signal filter further comprises an impedance matching element; the substrate supports the impedance matching element; the impedance matching element is electrically coupled to the notch filter and the wideband filter through the coupling circuit; and the wideband filter is a bandpass filter. ### Claim 10 (depends on 9) The signal filter according to claim 9, wherein: the first filtering unit, the first specific filtering property and the first specific filtering operation are a notch filter, a band-rejection filtering property and a band-rejection filtering operation respectively; the first specific filtering property further includes a first cutoff frequency and a frequency bandwidth; the second filtering unit, the second specific filtering property and the second specific filtering operation are a wideband filter, a wideband filtering property and a wideband filtering operation respectively; the second specific filtering property further includes a second cutoff frequency; the first and the second cutoff frequencies have a frequency difference therebetween; and a ratio of the frequency difference to the frequency bandwidth is within a preset ratio range being from 2.5% to 20%. ### Claim 11 (depends on 9) The signal filter according to claim 9, wherein: the signal filter is disposed in one of a first structure state and a second structure state. ### Claim 12 (depends on 11) The signal filter according to claim 11, wherein under a condition that the signal filter is in the first structure state: the substrate is an integrated multilayer substrate; each of the impedance matching element and the notch filter is disposed on the integrated multilayer substrate; and the wideband filter is disposed in the integrated multilayer substrate. ### Claim 13 (depends on 11) The signal filter according to claim 11, wherein under a condition that the signal filter is in the second structure state: the substrate is a printed circuit board; the coupling circuit is a printed circuit; and each of the impedance matching element, the notch filter and the wideband filter is disposed on the printed circuit board. ### Claim 14 (depends on 9) The signal filter according to claim 9, wherein: the first specific filtering property further includes a frequency bandwidth; the first specific filtering property includes a relatively high quality factor and a relatively low coupling coefficient; the relatively high quality factor ranges from 950 to 3500; the second specific filtering property includes a relatively low quality factor and a relatively high coupling coefficient; a coupling ratio associated with the relatively high coupling coefficient ranges from 30% to 60%; and a shape factor associated with the frequency bandwidth is within a preset shape factor range being from 0.4 to 0.8. ### Claim 15 A signal filter comprising: a notch filter configured to perform a band-rejection filtering operation according to a band-rejection filtering property; and a wideband filter coupled to the notch filter, and configured to perform a wideband filtering operation according to a wideband filtering property, wherein: the band-rejection filtering property includes a first cutoff frequency and a frequency bandwidth; the wideband filtering property includes a second cutoff frequency, a relatively low quality factor and a relatively high coupling coefficient; the first and the second cutoff frequencies have a frequency difference therebetween; a ratio of the frequency difference to the frequency bandwidth is within a preset ratio range being from 2.5% to 20%; the signal filter further comprises a coupling substrate and an impedance matching element; the coupling substrate supports the notch filter, the wideband filter and the impedance matching element, and includes a coupling circuit; the notch filter is electrically coupled to the wideband filter through the coupling circuit; the impedance matching element is electrically coupled to the notch filter and the wideband filter through the coupling circuit; and the wideband filter is a bandpass filter. ### Claim 16 (depends on 15) The signal filter according to claim 15, wherein: the signal filter is in one of a first structure state and a second structure state. ### Claim 17 (depends on 16) The signal filter according to claim 16, wherein under a condition that the signal filter is in the first structure state: the coupling substrate is an integrated multilayer substrate; each of the impedance matching element and the notch filter is disposed on the integrated multilayer substrate; and the wideband filter is disposed into the integrated multilayer substrate. ### Claim 18 (depends on 16) The signal filter according to claim 16, wherein under a condition that the signal filter is in the second structure state: the coupling substrate is a printed circuit board; the coupling circuit is a printed circuit; and each of the impedance matching element, the notch filter and the wideband filter is disposed on the printed circuit board. ### Claim 19 (depends on 15) The signal filter according to claim 15, wherein: the band-rejection filtering property further includes a relatively high quality factor and a relatively low coupling coefficient, the relatively high quality factor ranges from 950 to 3500; the wideband filtering property further includes a relatively low quality factor and a relatively high coupling coefficient, and a coupling ratio associated with the relatively high coupling coefficient ranges from 30% to 60%. ### Claim 20 (depends on 15) The signal filter according to claim 15, wherein a shape factor associated with the frequency bandwidth is within a preset shape factor range being from 0.4 to 0.8.