Abstract: A method is described for selecting an electromagnetic radiation (EMR) frequency causing substantially uniform heating in cylindrical biological tissue specimens, having a typical cross-sectional dimension, d, and known electrical properties, by an annular applicator configured for applicator-specimen impedence matching. Accordingly, an annular applicator system (10) comprises an EMR source (32) having a selected frequency wavelength in a specimen (20) between two-thirds and twice the specimen dimension, d. Connected to the source (32) is an annular applicator apparatus (12) formed of four applicator segments (16), circumferentially arranged to form an axial specimen receiving opening (18). A composite EMR emitting aperture (22), formed around the opening (18) has an axial height to circumferential width ratio causing matching, at the selected frequency, between a characteristic impedance of the apparatus (12) and a load impedance of the specimen (20) as seen through the aperture.

Abstract: Invasive hyperthermia apparatus includes an electromagnetic energy radiation source, and a plurality of applicators. Each applicator is adapted for insertion into body tissue and radiating electromagnetic energy therein. Interconnected between the applicators and the radiation source are a power splitter and a plurality of line stretchers for providing the applicator with electromagnetic energy in a preselected frequency - phase power relationship. The applicators, power splitter and line stretchers are operative for causing constructive interference between emitted electromagnetic radiation when the applicators are inserted into body tissue in a preselected spaced apart relationship.

Abstract: Apparatus for electromagnetic radiation of living tissue, such as human tissue, or tissue simulating matter, comprises an electromagnetic radiation source having a dynamic frequency range of at least about 5 to 1, and preferably 10 to 1. Electrically connected to the source by a coaxial cable is a broadband applicator adapted for emitting electromagnetic radiation into tissue and the like. Parallel plate type radiation launching portions of the applicator are configured to have a characteristic impedance, throughout the dynamic frequency range, approximately equal to the impedance of specimens to be irradiated, which for human tissue, between 50 MHz - 2000 MHz, is approximately 50 ohms. A transition for interconnecting the coaxial cable to the parallel plate launching portion is configured to provide a relatively gradual coaxial to parallel plate transition at constant characteristic impedance throughout the dynamic frequency range.

Abstract: Disclosed is a system for irradiating living bodies, or portions thereof, using electromagnetic radiation (EMR). A source or generator provides electromagnetic energy at a selected frequency, within an operational band width, via a coaxial cable to an applicator for radiation into living tissue. The source, cable, and applicator each have a characteristic impedance approximately equal to the average impedance of the living tissue over a broad frequency band, thus enabling efficient operation of the apparatus without using auxiliary impedance matching devices. The applicator is of a waveguide transmission line type enabling efficient transmission and radiation of the electromagnetic energy and further incorporates means for cooling surface portions of the living tissue during radiation thereof. Selective dielectric loading of the applicator enables shaping of the radiated power to a preselected distribution.

Abstract: Apparatus for electromagnetic radiation of living tissue, such as human tissue, or tissue simulating matter, comprises an electromagnetic radiation source having a dynamic frequency range of at least about 5 to 1, and preferably 10 to 1. Electrically connected to the source by a coaxial cable is a broadband applicator adapted for emitting electromagnetic radiation into tissue and the like. Parallel plate type radiation launching portions of the applicator are configured to have a characteristic impedance, throughout the dynamic frequency range, approximately equal to the impedance of specimens to be irradiated, which for human tissue, between 50 MHz-2000 MHz, is approximately 50 ohms. A transition for interconnecting the coaxial cable to the parallel plate launching portion is configured to provide a relatively gradual coaxial to parallel plate transition at constant characteristic impedance throughout the dynamic frequency range.

Abstract: A circuit for receiving an incoming RF signal incurring frequency drift and producing a local signal for tracking the incoming signal includes a phase-locked loop and means incorporated in the loop which compensate or correct for the frequency drift so as to maintain the loop locked on the incoming signal. The loop is defined by a phase detector, a DC amplifier and a voltage controlled oscillator connected in series. The correction means is coupled in parallel with the loop amplifier between the loop detector and amplifier at its one end and between the amplifier and a DC bias voltage supply terminal for the amplifier at its opposite end.