Duplexer for integration in communication terminals

A method of sharing an antenna between a receiver and a transmitter comprising:

• receiving an antenna quasi-transverse electromagnetic (TEM) wave signal having a first frequency from said antenna;
• propagating said antenna quasi-TEM wave signal in an electromagnetic coupling circuit;
• electromagnetically coupling said antenna quasi-TEM wave signal to a first filter having a first frequency bandpass comprising said first frequency, thereby obtaining a filtered antenna signal;
• propagating said filtered antenna signal to said receiver;
• receiving, from said transmitter, a transmitter signal having a second frequency different from said first frequency;
• propagating said transmitter signal in a second filter having a second frequency bandpass different from said first frequency bandpass and comprising said second frequency, thereby obtaining a transmitter quasi-TEM wave signal;
• electromagnetically coupling said transmitter quasi-TEM wave signal to said electromagnetic coupling circuit;
• and
• propagating said transmitter quasi-TEM wave signal to said antenna.

A method of fabricating a duplexer comprising:

• providing a dielectric substrate having a circuit-receiving surface and an opposite surface;
• forming a ground structure on one of said circuit-receiving surface and said opposite surface;
• forming, in said dielectric substrate, a first filter connectable to a first terminal and having a first frequency bandpass, and a second filter connectable to a second terminal and having a second frequency bandpass different from said first frequency bandpass, said first filter and said second filter each having at least one filter section deposited on said circuit-receiving surface;
• and
• depositing an uncovered coupling circuit connectable to a third terminal on said circuit-receiving surface between said first filter and said second filter, the coupling circuit being spaced apart from said first and second filter by a coupling gap and configured for electromagnetically coupling said first filter and said second filter together in order to electromagnetically couple a first quasi-transverse electromagnetic (TEM) wave signal having a first frequency within said first frequency bandpass between said uncovered coupling circuit and said first filter, and a second quasi-TEM wave signal having a second frequency within said second frequency bandpass between said uncovered coupling circuit and said second filter.