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Abstract

Method and apparatus for in vivo or in vitro selective deposition of microwave power patterns in lossy dielectric materials, particularly biological tissue. Configured as a needle-like probe, a miniature coaxial cable (1) having a circumferential gap (12) in the shield (2) is wrapped with an electrically thin dielectric substrate (18). The cable center conductor (6) extends immediately past gap (12) and is shorted to cable shield (2). A thin conductive dipole resonator (21) is positioned on substrate (18) and over gap (12) to achieve inductive coupling between the cable center conductor (6) and the dipole resonator (21) through gap (12). The ends of the dipole resonator (21) are capacitively (22) loaded so as to make the current on resonator (37) more uniform and to greatly reduce and stabilize the resonant frequency to be essentially insensitive to the dielectric properties of the surrounding material. A thin metal strip (27) is positioned on first superstrate (23) over and parallel to resonator (21), to diminish the hot spot near feed gap (12) and to make coupling to the surrounding lossy material (7) along the length of resonator (21) more uniform. Second superstrate (33), which could be a dielectric catheter, covers the entire probe assembly (30).

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First Claim