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US 5,778,308 AGranted
Adaptive antenna matching
AssigneeNokia Mobile Phones Ltd.
InventorsPeter Sroka, John Anthony Samuels
Life of this patent
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Abstract
In a mobile radio telephone, an adaptive impedance matching circuit (25) is positioned between a transmitting power amplifier (24) and a duplexer (18). The adaptive matching circuit (25) matches an antenna (17) to associated electronic circuitry, thereby optimising power transfer in an effort to maintain communication with a base station and to minimise power dissipation within the device itself. An adaptation algorithm is selected and implemented during idle periods when a reflection coefficient is identified as being large. The reactance of a passive pi network is incrementally modified and settings which achieve an optimum match are stored for subsequent use.
Claims28
An adaptive antenna-matching network for a radiotelephone, said network comprising;
- first and second reactive circuits interconnected by a third reactive circuit, wherein each of said first and said second reactive circuits comprises a shunt element, and said third reactive circuit comprises a series reactance operative for reversal between capacitive and inductive values of reactance;
- means responsive to the operating environment of the radiotelephone for directly measuring the level of reflected signals produced by the radio telephone's environment;
- means responsive to said level of reflected signals for electronically adjusting the impedances of individual ones of said reactive circuits of the matching network;
- wherein said measuring means and said adjusting means are operative to effect repetitive measurements of the reflected signals and repetitive adjustments of the impedance.
1 more element
An antenna-matching method for radiotelephones having an antenna-matching network, comprising the steps of:
- providing in said network first and second reactive circuits interconnected by a third reactive circuit, wherein each of said first and said second reactive circuits comprises a shunt element, and said third reactive circuit comprises a series reactance operative for reversal between capacitive and inductive values of reactance;
- measuring a level of reflected signals produced by the environment of a radiotelephone;
- and
- electronically adjusting an impedance of the matching network;
- wherein said adjusting step comprises steps of:
- electronically setting the reactance for said first reactive circuit in resonance when power is transmitted to the antenna;
- electronically setting said series reactance of said third reactive circuit in the network to a first predetermined reactance value;
- electronically adjusting the reactance of said second reactive circuit in the network over a range of reactive values;
- and
- selecting the optimum value for said second reactive circuit.
7 more elements
An antenna-matching method for radiotelephones having an antenna-matching network, comprising the steps of:
- measuring a level of reflected signals produced by the environment of a radiotelephone;
- and
- electronically adjusting an impedance of the matching network;
- wherein said adjusting step comprises steps of:
- electronically setting the reactance for a first parallel reactive circuit in the network resonance when power is transmitted to the antenna;
- electronically setting a series reactance circuit in the network to a first predetermined reactance value;
- electronically adjusting the reactance of a second parallel reactive circuit in the network over a range of reactive values;
- and
- selecting the optimum value for said second parallel reactive circuit;
- the method further comprising the steps of reversing the reactance of said series circuit from capacitive to inductive or vice versa after selecting said first optimum values;
- repeating said steps of adjusting said second parallel reactive circuit and selecting a second optimum value thereby;
- and
- selecting an optimum value providing the best reflection coefficient from said first and said second optimum values.
10 more elements
An adaptive antenna-matching network for a radiotelephone, said network comprising:
- first and second reactive circuits interconnected by a third reactive circuit, wherein each of said first and said second reactive circuits comprises a shunt element, and said third reactive circuit comprises a series reactance operative for reversal between capacitive and inductive values of reactance;
- means responsive to the operating environment of the radiotelephone for directly measuring the level of reflected signals produced by the radio telephone's environment;
- means responsive to said level of reflected signals for electronically adjusting the impedances of individual ones of said reactive circuits of the matching network.
An adaptive antenna-matching network for a radiotelephone, said network comprising:
- a first reactive circuit having a shunt reactance and a second reactive circuit having a series reactance, said shunt reactance having a frequency-selectable resonance, and said series reactance being operative for reversal between capacitive and inductive values of reactance;
- means responsive to the operating environment of the radiotelephone for directly measuring the level of reflected signals produced by the radio telephone's environment;
- and
- means responsive to said level of reflected signals for electronically adjusting the impedances of individual ones of said reactive circuits of the matching network.
1 more element
An adaptive antenna-matching network for a radiotelephone, said network comprising:
- first and second reactive circuits interconnected by a third reactive circuit, wherein each of said first and said second reactive circuits comprise a shunt reactance, and said third reactive circuit comprises a series reactance, one of said first and said second reactance circuits being operative to become transparent to a signal propagating through said antenna-matching network;
- means responsive to the operating environment of the radiotelephone for directly measuring the level of reflected signals produced by the radio telephone's environment;
- and
- means responsive to said level of reflected signals for electronically adjusting the impedances of individual ones of said reactive circuits of the matching network.
1 more element
An antenna-matching method for radiotelephones having an antenna-matching network, comprising the steps of:
- providing in said network a first reactive circuit having a shunt reactance and a second reactive circuit having a series reactance, said shunt reactance having a frequency-selectable resonance, and said series reactance being operative for reversal between capacitive and inductive values of reactance;
- measuring a level of reflected signals produced by the environment of a radiotelephone;
- and
- electronically adjusting an impedance of the matching network;
- wherein said adjusting step comprises steps of:
- electronically setting the reactance for said first reactive circuit in resonance when power is transmitted to the antenna;
- electronically setting said series reactance of said second reactive circuit in the network to a first predetermined reactance value;
- electronically adjusting the reactance of said first reactive circuit in the network over a range of reactive values;
- and
- selecting the optimum value for said first reactive circuit.
7 more elements
An antenna-matching method for radiotelephones having an antenna-matching network, comprising the steps of:
- providing in said network first and second reactive circuits interconnected by a third reactive circuit, wherein each of said first and said second reactive circuits comprise a shunt reactance, and said third reactive circuit comprises a series reactance, one of said first and said second reactance circuits being operative to become transparent to a signal propagating through said antenna-matching network;
- measuring a level of reflected signals produced by the environment of a radiotelephone;
- and
- electronically adjusting an impedance of the matching network;
- wherein said adjusting step comprises steps of:
- electronically setting the reactance for said first reactive circuit in resonance when power is transmitted to the antenna;
- electronically setting said series reactance of said third reactive circuit in the network to a first predetermined reactance value;
- electronically adjusting the reactance of said second reactive circuit in the network over a range of reactive values;
- and
- selecting the optimum value for said second reactive circuit.
7 more elements
Dependencies are inferred from the claim text.