# US 2023/0275334 A1 · Frequency selective coupler > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2023/0275334 A1 - Document ID: US20230275334A1 - Status: Published application - Kind: A1 - Application number: 17/681,306 - Filed: 2022-02-25 - Published: 2023-08-31 - Earliest claimed: 2022-02-25 - Assignees: QUALCOMM Incorporated - Applicants: Qualcomm Incorporated - Inventors: Yu-Chun LIU; Xiaomin YANG; Arjun RAVINDRAN - Web page: https://patentgrep.com/patent/US20230275334A1 ## CPC - H01P 1/212: suppressing or attenuating harmonic frequencies (H01P1/215 takes precedence) - H03H 7/48: Networks for connecting several sources or loads, working on the same frequency or frequency band, to a common load or source (phase shifters providing two or more output signals H03H7/21) - H01P 5/12: Coupling devices having more than two ports (H01P5/04 takes precedence) - H01P 5/184: {the guides being strip lines or microstrips} - H03H 7/0138: {Electrical filters or coupling circuits} - H03H 7/09: Filters comprising mutual inductance - H03H 2007/013: {Notch or bandstop filters} - H01P: WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE (operating at optical frequencies G02B) - H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P) ## Abstract A frequency selective coupler configured as a harmonic rejection filter includes an electromagnetic element configured to electromagnetically couple to a signal path between an output of a power amplifier and an antenna, an impedance network coupled between an isolated port of the coupler and ground, the impedance network configured to provide a harmonic filter response, and an electrically unconnected coupled port connected to the electromagnetic element. ## Claims ### Claim 1 A frequency selective coupler configured as a harmonic rejection filter, comprising: an electromagnetic element configured to electromagnetically couple to a signal path between an output of a power amplifier and an antenna; an impedance network coupled between an isolated port of the coupler and ground, the impedance network configured to provide a harmonic filter response; and an electrically unconnected coupled port connected to the electromagnetic element. ### Claim 2 (depends on 1) The coupler of claim 1, wherein the coupler is electromagnetically coupled to a power amplifier (PA) load line output. ### Claim 3 (depends on 1) The coupler of claim 1, wherein the impedance network comprises at least one of a resistor, an inductor and a capacitor. ### Claim 4 (depends on 3) The coupler of claim 3, wherein the capacitor has an adjustable capacitance. ### Claim 5 (depends on 1) The coupler of claim 1, wherein the electromagnetic element comprises an inductor. ### Claim 6 (depends on 1) The coupler of claim 1, wherein the harmonic filter response is a selectable notch response and occurs at a harmonic of the frequency of a signal on the signal path. ### Claim 7 (depends on 1) The coupler of claim 1, wherein the frequency at which the coupler provides the harmonic filter response comprises approximately 20 dB rejection compared to a signal on the signal path. ### Claim 8 (depends on 1) The coupler of claim 1, wherein the impedance network is configured to provide a plurality of selectable filter responses. ### Claim 9 (depends on 8) The coupler of claim 8, wherein the plurality of selectable filter responses are implemented in parallel with the signal path. ### Claim 10 (depends on 1) The coupler of claim 1, further comprising a first pair of switches configured to selectively connect the electrically unconnected coupled port and the impedance network to a first side of the electromagnetic element and a second pair of switches configured to selectively connect the electrically unconnected coupled port and the impedance network to a second side of the electromagnetic element. ### Claim 11 A frequency selective coupler associated with a filter, comprising: an electromagnetic element configured to electromagnetically couple to a signal path of a filter; an impedance network coupled between an isolated port of the coupler and ground, the impedance network configured to provide a filter response; and an electrically unconnected coupled port connected to the electromagnetic element. ### Claim 12 (depends on 11) The coupler of claim 11, wherein the coupler is electromagnetically coupled to an output of a filter. ### Claim 13 (depends on 11) The coupler of claim 11, wherein the impedance network comprises at least one of a resistor, an inductor and a capacitor. ### Claim 14 (depends on 13) The coupler of claim 13, wherein the capacitor comprises an adjustable capacitance. ### Claim 15 (depends on 11) The coupler of claim 11, wherein the impedance network is a parallel RC circuit. ### Claim 16 (depends on 11) The coupler of claim 11, wherein the filter response occurs at a harmonic of the frequency of the signal on the signal path. ### Claim 17 (depends on 11) The coupler of claim 11, wherein the frequency at which the coupler provides a filter response comprises approximately 20 dB rejection compared to a signal on the signal path. ### Claim 18 (depends on 11) The coupler of claim 11, wherein the impedance network is configured to provide a plurality of selectable filter responses. ### Claim 19 (depends on 11) The coupler of claim 11, wherein the filter is an electroacoustic filter. ### Claim 20 A frequency selective coupler, comprising: an electromagnetic element configured to electromagnetically couple to a signal path; an impedance network coupled between an isolated port of the coupler and ground, the impedance network configured to selectively adjust a frequency at which the coupler provides a filter response; and an electrically unconnected coupled port connected to the electromagnetic element. ### Claim 21 (depends on 20) The coupler of claim 20, wherein the coupler is electromagnetically coupled to a power amplifier (PA) load line output. ### Claim 22 (depends on 20) The coupler of claim 20, wherein the coupler is electromagnetically coupled to a filter. ### Claim 23 (depends on 20) The coupler of claim 20, wherein the impedance network is a parallel RC circuit. ### Claim 24 (depends on 20) The coupler of claim 20, wherein the impedance network comprises an adjustable capacitance. ### Claim 25 (depends on 20) The coupler of claim 20, wherein the electromagnetic element comprises an inductor. ### Claim 26 (depends on 20) The coupler of claim 20, wherein the filter response occurs at a harmonic of the frequency of the signal on the signal path. ### Claim 27 (depends on 20) The coupler of claim 20, wherein the impedance network is configured to provide a plurality of selectable filter responses. ### Claim 28 (depends on 27) The coupler of claim 27, wherein the plurality of selectable filter responses are implemented in parallel with the signal path. ### Claim 29 A method for providing signal rejection, comprising: electromagnetically coupling an electromagnetic element to a signal path; and selectively adjusting a frequency at which a filter response is provided to a signal on the signal path using a frequency selective coupler. ### Claim 30 (depends on 29) The method of claim 29, wherein the filter response occurs at a harmonic of the frequency of the signal on the signal path.