Abstract: Controlling the common mode impedance for a circuit, conductor, or multiple conductor cable by incorporating the circuit or conductor into the primary of a transformer. The secondary of the transformer is coupled to a secondary impedance selected so that the desired impedance is obtained. A capacitive shunt may be added to buffer the intrinsic primary impedance. The intrinsic impedance of a conductive antenna structure is controlled by deploying a portion of the antenna structure as the primary of a transformer and coupling the secondary of the transformer to a selectable secondary impedance.

Abstract: An apparatus for, and method of, replacing conventional antennas which transmit radio frequency energy from radio frequency transmitters. The invention provides for the use of any conductive surface as a transmitting antenna by taking advantage of the fact that any electrical conductor or surface that is 0.1 wavelengths or longer will radiate RF energy when injected with sufficient current. The RF current injecting antenna device, employing the principles of an instrument transformer, couples RF energy from a transmitter to a linear conductive element or a conductive surface. The useful frequency range that has been demonstrated for the device is 2 MHz to 1 GHz.

Abstract: An apparatus for, and method of, replacing conventional antennas which intercept radio frequency fields and develop electrical signals for input to an RF receiver. The invention eliminates the use of antennas by taking advantage of the fact that any electrical conductor or surface develops significant current when its length is approximately 0.1 wavelength long or longer of an intercepted RF field. The RF current-sensing coupled antenna device, employing the principles of an instrument transformer, transforms the current in a wire filament or metallic surface and conveys it to a receiver. The useful frequency range that has been demonstrated for the coupled antenna device is 100 kHz to 2 GHz.

Abstract: A TEM mode cell having an internal TEM element and at least one port on the cell, the cell comprising a stepped transmission line transformer coupling the internal TEM element to the port. The stepped transmission line transformer of the TEM mode cell has transfer characteristics selected to give maximum cancellation of VSWR in the cell and thereby enable optimum cell bandwidth. The TEM mode test cell comprises a hollow metallic housing having an enlarged center section with opposite open ends, and a pair of end sections, each end section closing off a respective one of the center section open ends and tapering to a distal end of reduced cross sectional area. A connector is provided at the distal end of each end section, and a stepped septum is mounted within the housing and insulated therefrom, the septum coupled to and extending between the connectors.