ACTIVE REDUCTION OF ELECTRIC FIELD GENERATED BY A TRANSMIT ANTENNA VIA AN AUXILLARY ANTENNA STRUCTURE
First Claim
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1. A method of operating a wireless communication device comprising a main antenna and an auxiliary antenna structure, the method comprising the steps of:
- reducing a first magnitude of an amplified RF signal to generate a drive signal having a second magnitude that is less than the first magnitude;
shifting a phase angle of the drive signal to generate a phase-shifted drive signal that is phase shifted with respect to the amplified RF signal; and
driving the main antenna with the amplified RF signal to radiate a first electric field having a first near-field component, and simultaneously driving the auxiliary antenna structure with the phase-shifted drive signal to radiate a second electric field having a second near-field component that reduces the magnitude of the first near-field component.
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Abstract
A wireless communication device and method includes an auxiliary antenna that can actively cancel at least a portion of a near-field component of an electric field generated by a main transmit antenna. The auxiliary antenna can help comply with specific absorption rate requirements and can reduce undesirable signal rectification in hearing aid components.
269 Citations
20 Claims
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1. A method of operating a wireless communication device comprising a main antenna and an auxiliary antenna structure, the method comprising the steps of:
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reducing a first magnitude of an amplified RF signal to generate a drive signal having a second magnitude that is less than the first magnitude; shifting a phase angle of the drive signal to generate a phase-shifted drive signal that is phase shifted with respect to the amplified RF signal; and driving the main antenna with the amplified RF signal to radiate a first electric field having a first near-field component, and simultaneously driving the auxiliary antenna structure with the phase-shifted drive signal to radiate a second electric field having a second near-field component that reduces the magnitude of the first near-field component. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A wireless communication device, comprising:
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a main antenna designed to radiate, in response to an amplified RF signal having a first magnitude, a first electric field having a first near-field component; a coupler designed to receive the amplified RF signal and to reduce the first magnitude of the amplified RF signal to generate a drive signal having a phase angle and a second magnitude that is less than the first magnitude; a phase shifter, coupled to the coupler and being designed to receive the drive signal, the phase shifter being designed to shift the phase angle of the drive signal to generate a phase-shifted drive signal that is phase shifted with respect to the amplified RF signal; and an auxiliary antenna structure coupled to the phase shifter and being designed to radiate, in response to the phase-shifted drive signal, a second electric field having a second near-field component. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A wireless communication device, comprising:
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a housing; an RF front end module designed to generate an amplified RF signal having a first magnitude; a main antenna designed to radiate a first electric field in response to the amplified RF signal, wherein the first electric field has a first near-field component having a maximum intensity at a hot spot location; a coupler designed to receive the amplified RF signal and to reduce the first magnitude of the amplified RF signal to generate a drive signal having a second magnitude that is less than the first magnitude; a phase shifter coupled to the coupler and being designed to receive the drive signal and shift the phase of the drive signal to generate a phase-shifted drive signal having a phase angle that is shifted with respect to the amplified RF signal; an auxiliary antenna structure disposed inside the housing and being coupled to the phase shifter; and an earpeice speaker integrated with the housing, wherein the auxiliary antenna structure is disposed underneath the hot spot location near the earpeice speaker, and is designed to radiate, in response to the phase-shifted drive signal, a second electric field having a second near-field component that destructively interferes with and reduces a magnitude of the first near-field component that is incident at the hot spot location.
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Specification