# US 2014/0155005 A1 · Mobile wireless communications device with reduced harmonics resulting from metal shield coupling > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0155005 A1 - Document ID: US20140155005A1 - Status: Published application - Kind: A1 - Application number: 14/093,788 - Filed: 2013-12-02 - Published: 2014-06-05 - Earliest claimed: 2008-05-08 - Assignees: BlackBerry Limited - Applicants: Blackberry Limited - Inventors: LIZHONG ZHU; GEORGE SOLIMAN MANKARUSE; MICHAEL STEPHEN CORRIGAN - Web page: https://patentgrep.com/patent/US20140155005A1 ## CPC - H04B 1/0475: {with means for limiting noise, interference or distortion (H04B1/0483 takes precedence)} - H01Q 1/2241: {used in or for vehicle tyres} - Y10T 29/49018: with other electrical component - H04B: TRANSMISSION - H01Q: ANTENNAS, i.e. RADIO AERIALS (radiators or antennas for microwave heating H05B6/72) - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract A mobile wireless communications device includes a housing, antenna, and circuit board carried by the housing and having radio frequency (RF) circuitry operative with the antenna for receiving and transmitting RF signals through the antenna. A power amplifier is connected within a transmission line for amplifying RF signals to be transmitted over the transmission line to the antenna. An antenna switch is connected to the antenna and RF circuitry. An RF shield surrounds the power amplifier and antenna switch and isolates the power amplifier and antenna switch from the antenna and RF circuitry. A low pass filter is connected to the power amplifier and antenna switch for reducing any RF coupling of voltage standing waves of upper harmonic frequencies from the power amplifier into the antenna switch through the RF shield while maintaining transmission of signals through the transmission line at a desired fundamental frequency. ## Claims ### Claim at position 1 1-22. (canceled) ### Claim 23 An electronic device comprising: an antenna switch; a power amplifier; a transmission path coupling said power amplifier and said antenna switch; and an RF shield surrounding said power amplifier, said antenna switch, and said transmission path; said transmission path comprising a transmission line, an inductor coupled in series with said transmission line, and at least one component coupled to said inductor to define therewith a low pass filter configured to reduce RF coupling from said power amplifier into said antenna switch via said RF shield. ### Claim 24 (depends on 23) The electronic device according to claim 23, wherein said at least one component comprises a first capacitor and a first resistor coupled in series between a first terminal of said inductor and a voltage reference. ### Claim 25 (depends on 24) The electronic device according to claim 24, wherein said at least one component further comprises a second resistor coupled in parallel with said inductor. ### Claim 26 (depends on 25) The electronic device according to claim 25, wherein said at least one component further comprises a second capacitor coupled between a second terminal of said inductor and the voltage reference. ### Claim 27 (depends on 23) The electronic device according to claim 23, wherein said RF shield comprises a metallic housing. ### Claim 28 (depends on 27) The electronic device according to claim 27, wherein metallic housing comprises a top and sides extending therefrom. ### Claim 29 (depends on 23) The electronic device according to claim 23, further comprising RF circuitry coupled to said power amplifier and to said antenna switch. ### Claim 30 (depends on 29) The electronic device according to claim 29, wherein said RF circuitry comprises RF circuitry for Global System, for Mobile (GSM) signals. ### Claim 31 (depends on 29) The electronic device according to claim 29, wherein said RF circuitry comprises a transceiver chip set. ### Claim 32 An electronic device comprising: an antenna switch; a power amplifier; a transmission path coupling said power amplifier and said antenna switch; an RF shield surrounding said power amplifier, said antenna switch, and said transmission path; said transmission path comprising a transmission line, an inductor coupled in series at a medial portion of said transmission line, a first capacitor coupled between a first terminal of said inductor and a voltage reference, and a second capacitor coupled between a second terminal of said inductor and the voltage reference. ### Claim 33 (depends on 32) The electronic device according to claim 32, wherein said transmission path further comprises a first resistor coupled in series between said first capacitor and the voltage reference. ### Claim 34 (depends on 33) The electronic device according to claim 33, wherein said transmission path further comprises a second resistor coupled in parallel with said inductor. ### Claim 35 (depends on 32) The electronic device according to claim 32, wherein said RF shield comprises a metallic housing. ### Claim 36 (depends on 35) The electronic device according to claim 35, wherein metallic housing comprises a top and sides extending therefrom. ### Claim 37 (depends on 32) The electronic device according to claim 32, further comprising RF circuitry coupled to said power amplifier and to said antenna switch. ### Claim 38 A method for making an electronic device comprising: coupling an antenna switch to a power amplifier via a transmission path and within an RF shield; and wherein the transmission path comprises a transmission line and an inductor coupled in series therewith, and at least one component coupled to the inductor to define therewith a low pass filter configured to reduce RF coupling from the power amplifier into the antenna switch via the RF shield. ### Claim 39 (depends on 38) The method according to claim 38, wherein the at least one component comprises a first capacitor and a first resistor coupled in series between a first terminal of the inductor and a voltage reference. ### Claim 40 (depends on 39) The method according to claim 39, wherein the at least one component further comprises a second resistor coupled in parallel with the inductor. ### Claim 41 (depends on 40) The method according to claim 40, wherein the at least one component further comprises a second capacitor coupled between a second terminal of the inductor and the voltage reference. ### Claim 42 (depends on 38) The method according to claim 38, further comprising coupling RF circuitry to the power amplifier and to the antenna switch.