Methods and apparatus for matching an antenna
First Claim
1. An apparatus for matching an antenna of a radio device, said apparatus comprising:
- a power amplifier comprising a power measuring signal output interface;
a directional coupler comprising an impedance measuring signal output interface;
a control unit coupled to said power measuring signal output interface and said impedance measuring signal interface; and
a reactive matching circuit controlled at least in part by said control unit;
wherein said power amplifier, directional coupler and reactive matching circuit are positioned along a transmission path of said radio device.
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Accused Products
Abstract
A method and an arrangement for matching the antenna of a radio device in transmitting condition. The antenna impedance in the output of the power amplifier of a transmitter is adjusted by means of a π-shaped reactive matching circuit, the component values of which can be selected from a relatively wide array of the alternatives. The component values are selected using multiple-way switches, which only are located in the transverse branches of the matching circuit. The switches are set by the control unit, input variables of which being the SWR value provided by the directional coupler, the operating band used each time and a value of the transmitting power. The matching is based on an adjusting process to be executed at regular intervals, in which process the control unit tries different combinations of the switch states and finally selects the combination, which brings the lowest SWR value.
423 Citations
20 Claims
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1. An apparatus for matching an antenna of a radio device, said apparatus comprising:
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a power amplifier comprising a power measuring signal output interface; a directional coupler comprising an impedance measuring signal output interface; a control unit coupled to said power measuring signal output interface and said impedance measuring signal interface; and a reactive matching circuit controlled at least in part by said control unit; wherein said power amplifier, directional coupler and reactive matching circuit are positioned along a transmission path of said radio device. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. An apparatus for matching an antenna of a radio device, wherein a transmitter of the radio device comprises a power amplifier controllable by its output power and a transmission path from the power amplifier to the antenna, the apparatus comprising:
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a directional coupler in said transmission path to measure a level of a signal transmitted to the antenna and of a signal reflected from the antenna; apparatus configured to determine a standing wave ratio (SWR) value of a signal in the transmission path of the antenna based at least in part on the measured signals provided with the directional coupler; a pi-shaped adjustable reactive matching circuit with a control unit, and further comprising a longitudinal portion of the matching circuit that has a constant capacitance or inductance, and a plurality of transverse portions comprising at least one multiple-way switch, a common terminal of which is coupled to a separate conductor of said transmission path and wherein each change-over terminal is coupled to a ground conductor of the transmission path through a reactive element, the control unit having a first input adapted for operative coupling to a setting unit of an operating band of the radio device, and the control unit being operatively coupled to said directional coupler from its input side, and to said at least one switch in the matching circuit from its output side so as to permit setting of the switches, the control unit comprising; apparatus configured to define a trial array of the state combinations of the switches in the matching circuit based at least in part on a certain value of the transmitting power, an information associated with the operating band and the SWR value; apparatus configured to set the switches of the matching circuit in turn to the states according to each state combination of the trial array to determine the SWR values correspond to these combinations; apparatus configured to compare the determined SWR values and for finding the lowest one of them; and apparatus configured to start an adjusting process of the antenna matching at regular intervals. - View Dependent Claims (18, 19, 20)
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Specification