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;
radio frequency (RF) circuitry carried within the housing;
a circuit board carried by the housing and a microphone mounted on the circuit board;
an RF shield surrounding and isolating said microphone from said RF circuitry and shielding said microphone from radiated energy generated from the RF circuitry;
a cover extending over said RF shield;
an acoustical tube extending from the housing through the RF shield to the microphone, and configured to permit sound to pass from the microphone through the cover; and
an isolation ring surrounding at least a portion of the acoustical tube and configured to provide RF and acoustic sealing.
2. The mobile wireless communications device according to claim 1 , wherein said RF circuitry is mounted on the circuit board.
3. The mobile wireless communications device according to claim 1 , and further comprising a power amplifier carried within the housing and operative with the RF circuitry, wherein said RF shield shields the microphone from any radiated energy generated from the power amplifier.
4. The mobile wireless communications device according to claim 1 , and further comprising an antenna carried within the housing and operative with the RF circuitry, wherein said RF shield shields the microphone from any radiated energy generated from the antenna.
5. The mobile wireless communications device according to claim 4 , and further comprising a plurality of circuit boards and wherein at least one of said plurality of circuit boards comprises an antenna circuit board on which the antenna is mounted.
6. The mobile wireless communications device according to claim 1 , wherein said RF shield comprises a metallic housing secured to the circuit board and surrounding said microphone.
7. The mobile wireless communications device according to claim 1 , wherein said RF circuitry comprises a transceiver chip set.
8. The mobile wireless communications device according to claim 1 , wherein said RF circuitry is operative for generating Global Systems for Mobile (GSM) packet bursts.
9. The mobile wireless communications device according to claim 1 , and further comprising a first isolation compartment on which RF circuitry is positioned.
10. The mobile wireless communications device according to claim 1 , wherein said microphone comprises a surface mounted microphone and associated filter component within the RF shield.
11. The mobile wireless communications device according to claim 1 , and further comprising a sound opening in said cover engaging said acoustical tube, wherein said sound opening is about 2.0 mm or less and configured for obtaining a desired frequency response.
12. A method for making a mobile wireless communications device, which comprises:
providing a housing, radio frequency (RF) circuitry carried within the housing, a circuit board carried by the housing and a microphone mounted on the circuit board and operatively connected to said RF circuitry;
isolating the microphone from the RF circuitry for shielding the microphone from radiated energy generated from the RF circuitry by securing a metallic housing to the circuit board that covers the microphone, and positioning a cover over the RF shield and an acoustical tube extending from the cover to the microphone, and configured to permit sound to pass from the microphone through the cover; and
surrounding at least a portion of the acoustical tube with a isolation ring to provide RF and acoustic sealing.
13. The method according to claim 12 , which further comprises positioning the RF circuitry on the circuit board.
14. The method according to claim 12 , which further comprises positioning a power amplifier within the housing and operative with the RF circuitry and shielding the microphone from any radiated energy generated from the power amplifier.
15. The method according to claim 12 , which further comprises positioning an antenna within the housing and operative with the RF circuitry and shielding the microphone from any radiated energy generated from the antenna.
16. The method according to claim 15 , which further comprises positioning a plurality of circuit boards within the housing and forming at least one of the circuit boards as an antenna circuit board on which the antenna is mounted.
17. The method according to claim 12 , which further comprises forming an isolation compartment on the circuit board on which RF circuitry is positioned.
18. The method according to claim 17 , which further comprises positioning the microphone adjacent the isolation compartment.
19. The method according to claim 12 , which further comprises surface mounting the microphone on the circuit board.