Abstract: An antenna system including an array of conductors connected to a feed line, wherein the array is configured to (1) emit electromagnetic radiation in response to an input signal being input to the array through the feed line or (2) output an output signal to the feed line in response to electromagnetic radiation being received on the array; and a director disposed in front of the array, wherein the director has a first reactive load having a complex impedance that is tailored to increase a directivity of the antenna system by reactively loading the conductors.

Abstract: An antenna system including an array of conductors connected to a feed line, wherein the array is configured to (1) emit electromagnetic radiation in response to an input signal being input to the array through the feed line or (2) output an output signal to the feed line in response to electromagnetic radiation being received on the array; and a director disposed in front of the array, wherein the director has a first reactive load having a complex impedance that is tailored to increase a directivity of the antenna system by reactively loading the conductors.

Abstract: Typical electrical impedance tomography (“EIT”) systems apply current to a body under test and measure the induced voltages on the surface and then through an inverse process, reconstruct an approximation to the electrical conductivity in the interior. The EIT system described herein employs a new approach to evaluating the interior electrical conductivity by using a virtual short that allows both current and voltages to be measured at various locations on the body under test. The architecture of this system is described, distinguishability of embedded conductive anomalies is evaluated, typical error sources associated with a virtual short measurement is discussed in the context of electrical impedance tomography, and a new imaging system is discussed.