Methods and apparatuses for adaptively controlling antenna parameters to enhance efficiency and maintain antenna size compactness

A communications apparatus comprising:

• a first antenna having a resonant frequency in a first frequency band;
• a second antenna having a resonant frequency in a second frequency band;
• a first and a second power amplifier respectively supplying a first and a second signal for transmitting;
• a switching element for switchably supplying the first or the second signal for transmitting to the first antenna or to the second antenna responsive to the frequency of the first and the second signal for transmitting;
• and
• an impedance controller for controlling the impedance of the first and the second antennas responsive to a power-related parameter.

A communications apparatus comprising:

• a first antenna having a resonant frequency in a first frequency band;
• a second antenna having a resonant frequency in a second frequency band, the first and the second antennas presenting an antenna impedance less than about 50 ohms at a respective resonant frequency;
• a signal combiner connected to the first and the second antennas;
• a first and a second power amplifier respectively supplying a first and a second signal for transmitting;
• and
• a first switching element for switchably supplying the first or the second signal for transmitting to the signal combiner, the signal combiner supplying the first or the second signal for transmitting to the first antenna or to the second antenna responsive to the frequency of the first and the second signal for transmitting;
• and
• a first and a second matching network disposed between the respective first and second power amplifiers and the switching element, the first and the second matching networks operative to control the power added efficiency or the efficiency of the first and the second power amplifiers.