Abstract: A catheter is used to insert a probe into a tumor undergoing hyperthermia treatment. The probe is designed to isotropically measure the electric field and temperature in the tumor during the hyperthermia treatment. The probe is constructed on a triangular prism and includes a dipole on each prism face oriented at an angle of 54.74 degrees relative to the axis of the prism. Each dipole includes rectifier means therein and the three dipoles are coupled serially using high resistivity lead means. In addition, high resistivity leads are used to couple the dipoles to a high input impedance amplifier. A pair of thermistors are coupled between the three dipoles, and high resistance lead means couple the thermistors to high input impedance amplifiers. A current source is used to provide current to the thermistors in a time shared manner when the electric field is not being measured.

Abstract: A current detector for detecting the high frequency current flowing in a conductor includes a coil of high resistivity material wound around an non-ferromagnetic core. The coil is arranged in a substantially closed loop configuration around the conductor carrying the current to be measured. The ratio of the winding spacing to the cross sectional area of the coil is maintained constant over the length of the winding. A shield of high resistivity material surrounds the coil and is spaced from the coils and the shield has a gap oriented along an azimuth of the closed loop winding and directed orthogonal to the net current direction of the current induced in the coil. The ends of the coil are coupled to a high impedance voltage detector through high resistivity leads and a relatively low value resistor is coupled between the leads to reduce the quality factor.

Abstract: A current detector for detecting the high frequency current flowing in a conductor includes a coil of high resistivity material wound around an non-ferromagnetic core. The coil is arranged in a substantially closed loop configuration around the conductor carrying the current to be measured. The ratio of the winding spacing to the cross sectional area of the coil is maintained constant over the length of the winding. A shield of high resistivity material surrounds the coil and is spaced from the coils and the shield has a gap oriented along an azimuth of the closed loop winding and directed orthogonal to the net current direction of the current induced in the coil. The ends of the coil are coupled to a high impedance voltage detector through high resistivity leads and a relatively low value resistor is coupled between the leads to reduce the quality factor.

Abstract: A broadband isotropic probe system simultaneously measuring the E- and H-field intensities of rf complex, near-field electromagnetic radiation comprises a set of three mutually orthogonal dipole antennas and a set of three mutually orthogonal loop antennas located within the same volume of space. Each antenna has associated circuitry comprising a frequency-response-shaping filter and diode detector to provide a frequency response which is flat over the desired frequency bandwidth. The lengths of the dipoles are kept electrically small so that the EM fields are not perturbed. The diameters of the loops are kept electrically small so that the E-field pickup will be negligible. Coupling between any of the probe's antennas is also minimized by the use of electrically small antennas. Circuit means based on the use of square law detectors is also provided, the circuit including an arrangement of analog or digital data processing portions leading into a display means and a data recorder.

Abstract: A novel antenna is disclosed which provides inherent filtering action by ch the frequency response curve of the antenna can be shaped. In the preferred inventive embodiment, the antenna comprises at least one elongated receiving element, and preferably two such elements in the form of a dipole, both elements being constructed, at least in part, of an electrically resistive material. A detector, such as a diode detector, is directly coupled to the receiving elements. The resistance of the receiving element and the capacitances of the receiving element and the detector form a distributed parameter RC filter, the values of which parameters can be carefully controlled so as to provide the desired frequency response curve shaping. In the preferred inventive embodiment, a conductive strip is disposed along the length of and preferably to both sides of each receiving element, with a layer of dielectric material being sandwiched therebetween, whereby the filtering action is enhanced.