Extended bandwidth dual-band patch antenna systems and associated methods of broadband operation

A dual-band antenna system for use with a transceiver in transmitting and receiving circularly polarized radio signals, said antenna system comprising:

• (a) a patch antenna having a first feed and a second feed which are arranged orthogonally;
• (b) a first circuit branch comprising at least one reactive element coupled to said first and second feeds for changing the resonant frequency of said patch antenna to a first resonant frequency and for increasing the operating bandwidth of said patch antenna about said first resonant frequency;
• (c) a second circuit branch comprising at least one reactive element coupled to said first and second feeds for setting the resonant frequency of said patch antenna to a second resonant frequency and for increasing the operating bandwidth of said patch antenna about said second resonant frequency;
• d) selection means for electrically connecting said patch antenna to one of said first or second circuit branches while electrically isolating the other of said first or second circuit branches from said patch antenna;
• and
• (e) coupling means for coupling signals from said transmitter to one of said first or second circuit branches in phase quadrature and for combining phase quadrature signals from the other of said first and second circuit branches for coupling to said receiver.

A method for transmitting electrical signals from a transmitter and for receiving electrical signals at a receiver using an antenna system comprising a patch antenna and first and second circuit branches for changing the resonant frequency of the patch antenna to first and second resonant frequencies, the method comprising:

• (a) coupling signals received by the patch antenna to the second circuit branch while electrically isolating the transmitter and the first circuit branch from the patch antenna;
• (b) coupling signals from the second circuit branch to the receiver while electrically isolating the transmitter and the first circuit branch from the patch antenna;
• (c) coupling signals from the transmitter to the first circuit branch while electrically isolating the receiver and the second circuit branch from the patch antenna;
• and
• (d) coupling signals from the first circuit branch to the patch antenna while electrically isolating the receiver and the second circuit branch from the patch antenna.

A dual-band radiotelephone for transmitting and receiving radio frequency signals comprising:

• (a) a transmitter;
• (b) a receiver;
• (c) a user interface;
• (d) a patch antenna;
• (e) a first circuit branch for changing the resonant frequency of said patch antenna to a first resonant frequency;
• (f) a second circuit branch for exciting said patch antenna at a second resonant frequency;
• (g) coupling means for coupling the signal from one of said first or second circuit branches to said receiver and for coupling the signal from said transmitter to the other of said first or second circuit branches;
• and
• (h) selection means for electrically coupling said patch antenna to either said first circuit branch or said second circuit branch.