Mobile communication device and impedance matching method thereof
First Claim
1. A mobile communication device comprising:
- an antenna;
a power amplifier;
a tunable matching circuit coupled between the antenna and the power amplifier, determining an output impedance encountered by a radio frequency (RF) signal transmitted by the power amplifier to the antenna when the RF signal enters the tunable matching circuit;
a power detection circuit coupled between the antenna and the power amplifier, detecting a forward power of the RF signal entering the antenna and a reflected power of the antenna; and
a controller coupled to the tunable matching circuit and the power detection circuit, tuning the tunable matching circuit according to a frequency range currently used by the mobile communication device, the forward power and the reflected power to steer the output impedance toward a corresponding load-pull impedance that the power amplifier has in the frequency range,wherein the controller tunes the tunable matching circuit according to the frequency range, the forward power and the reflected power to steer the output impedance toward the load-pull impedance when a strength of a signal from a base station is smaller than a threshold value.
1 Assignment
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Accused Products
Abstract
A mobile communication device and an impedance matching method thereof are provided. The mobile communication device includes an antenna, a power amplifier, a tunable matching circuit, a power detection circuit and a controller. The tunable matching circuit determines an output impedance encountered by a radio frequency (RF) signal transmitted by the power amplifier to the antenna when the RF signal enters the tunable matching circuit. The power detection circuit detects a forward power of the RF signal entering the antenna and a reflected power of the antenna. The controller tunes the tunable matching circuit according to a frequency range currently used by the mobile communication device, the forward power and the reflected power to steer the output impedance toward a corresponding load-pull impedance that the power amplifier has in the frequency range.
4 Citations
14 Claims
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1. A mobile communication device comprising:
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an antenna; a power amplifier; a tunable matching circuit coupled between the antenna and the power amplifier, determining an output impedance encountered by a radio frequency (RF) signal transmitted by the power amplifier to the antenna when the RF signal enters the tunable matching circuit; a power detection circuit coupled between the antenna and the power amplifier, detecting a forward power of the RF signal entering the antenna and a reflected power of the antenna; and a controller coupled to the tunable matching circuit and the power detection circuit, tuning the tunable matching circuit according to a frequency range currently used by the mobile communication device, the forward power and the reflected power to steer the output impedance toward a corresponding load-pull impedance that the power amplifier has in the frequency range, wherein the controller tunes the tunable matching circuit according to the frequency range, the forward power and the reflected power to steer the output impedance toward the load-pull impedance when a strength of a signal from a base station is smaller than a threshold value. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An impedance matching method adapted for a mobile communication device, the mobile communication device comprising an antenna, a tunable matching circuit and a power amplifier, the tunable matching circuit being coupled between the antenna and the power amplifier and determining an output impedance encountered by a radio frequency (RF) signal transmitted by the power amplifier to the antenna when the RF signal enters the tunable matching circuit, the impedance matching method comprising:
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detecting a forward power of the RF signal entering the antenna and a reflected power of the antenna; tuning the tunable matching circuit according to a frequency range currently used by the mobile communication device, the forward power and the reflected power to steer the output impedance toward a corresponding load-pull impedance that the power amplifier has in the frequency range; and tuning the tunable matching circuit according to the frequency range, the forward power and the reflected power to steer the output impedance toward the load-pull impedance when a strength of a signal from a base station is smaller than a threshold value. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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Specification