Mobile wireless communications device with reduced microphone noise from radio frequency communications circuitry
View Patent ↗A mobile wireless communications device includes a housing and circuit board in the housing and having radio frequency (RF) circuitry and a power amplifier and microphone mounted thereon. An antenna is carried within the housing and operative with the RF circuitry. An RF shield surrounds and isolates the microphone from the RF circuitry, power amplifier and antenna and shields the microphone from radiated energy generated from the RF circuitry, antenna or power amplifier.
1. A mobile wireless communications device comprising:
a housing;
a circuit board carried by said housing and having radio frequency (RF) circuitry and a power amplifier carried by the circuit board;
a microphone mounted on the circuit board and operatively connected to said RF circuitry;
an antenna carried within the housing and operative with said RF circuitry;
an RF shield surrounding and isolating said microphone from the RF circuitry, power amplifier, and antenna, and shielding said microphone from radiated energy generated from the RF circuitry, antenna or power amplifier, said RF shield having a sound opening over said microphone; and
a cover extending over said RF shield and having a sound opening aligned with the sound opening in the RF shield and an acoustical tube extending from the sound opening in the cover through the sound opening in the RF shield to the microphone.
2. A mobile wireless communications device according to claim 1 , wherein said RF shield comprises a metallic housing secured to said circuit board and surrounding said microphone.
3. A mobile wireless communications device according to claim 1 , wherein said RF circuitry comprises a transceiver chip set.
4. A mobile wireless communications device according to claim 1 , wherein said RF circuitry is operative for generating Global Systems for Mobile (GSM) packet bursts.
5. A mobile wireless communications device according to claim 1 , and further comprising a first isolation compartment in which RF circuitry is positioned, and a second isolation compartment in which said power amplifier is positioned.
6. A mobile wireless communications device according to claim 5 , wherein said RF shield surrounding said microphone is positioned adjacent said isolation compartments.
7. A mobile wireless communications device according to claim 1 , wherein said microphone comprises a surface mounted microphone and associated filter component within the RF shield.
8. A mobile wireless communications device according to claim 1 , wherein the sound opening in said cover engaging said acoustical tube is about 2.0 mm or less and configured for obtaining a desired frequency response.
9. A mobile wireless communications device comprising:
a housing;
a circuit board carried by said housing and having radio frequency (RF) circuitry and a power amplifier carried by the circuit board;
a microphone mounted on the circuit board and operatively connected to said RF circuitry;
an antenna carried within the housing and operative with said RF circuitry;
an RF shield surrounding and isolating said microphone from the RF circuitry, power amplifier, and antenna, and shielding said microphone from radiated energy generated from the RF circuitry, antenna or power amplifier, said RF shield having a sound opening over said microphone;
a cover extending over said housing at said microphone and having a sound opening aligned with the sound opening in the RF shield;
an acoustical tube extending from the sound opening in the cover to the sound opening in the RF shield and through said RF shield to said microphone; and
an isolation ring surrounding said acoustical tube between said cover and RF shield to provide RF and acoustical sealing.
10. A mobile wireless communications device according to claim 9 , wherein said housing has an upper and lower portion and said microphone, RF circuitry, and power amplifier are positioned within a lower portion of the housing.
11. A mobile wireless communications device according to claim 10 , wherein the antenna is positioned within a lower portion of the housing.
12. A mobile wireless communications device according to claim 9 , wherein said RF shield comprises a metallic housing secured to said circuit board and surrounding said microphone.
13. A mobile wireless communications device according to claim 9 , wherein said RF circuitry comprises a transceiver chip set.
14. A mobile wireless communications device according to claim 9 , wherein said RF circuitry is operative for generating Global Systems for Mobile (GSM) packet bursts.
15. A mobile wireless communications device according to claim 9 , and further comprising a first isolation compartment in which RF circuitry is positioned and a second isolation compartment in which said power amplifier is positioned.
16. A mobile wireless communications device according to claim 9 , wherein said RF shield surrounding said microphone is positioned adjacent said isolation compartments.
17. A mobile wireless communications device according to claim 9 , wherein said microphone comprises a surface mounted microphone and associated filtering components within the RF shield.
18. A mobile wireless communications device according to claim 9 , wherein the sound opening engaging said acoustical tube at the cover is about 2.0 mm or less and configured for obtaining a desired frequency response.
19. A method for making a mobile wireless communications device, which comprises:
providing a housing, a circuit board carried by the housing, radio frequency (RF) circuitry and a power amplifier carried by the circuit board, a microphone mounted on the circuit board and operatively connected to said RF circuitry, and an antenna positioned within the housing and operatively connected to the RF circuitry; and
isolating the microphone from the RF circuitry, power amplifier and antenna for shielding the microphone from radiated energy generated from the RF circuitry, antenna or power amplifier by securing a metallic housing to the circuit board that covers the microphone for shielding the microphone from the radiated energy, and including a sound opening in the RF shield, and positioning a cover over the RF shield and having a sound opening aligned with the sound opening in the RF shield and an acoustical tube extending from the sound opening in the cover through the sound opening in the RF shield to the microphone.
20. A method according to claim 19 , which further comprises forming a first isolation compartment on the circuit board in which RF circuitry is positioned and a second isolation compartment in which the power amplifier is positioned.
21. A method according to claim 20 , which further comprises positioning the microphone adjacent the isolation compartments.
22. A method according to claim 19 , which further comprises surface mounting the microphone on the circuit board.