Abstract: An example system for microvascular assessment of a patient can include: a fundus imaging device including: a camera configured to capture one or more images of an eye of the patient; and at least one light source; and a microvascular assessment computing device including: a processor; and memory encoding instructions which, when executed by the processor, cause the system to: activate the light source to direct light at a fundus of the eye of the patient; capture, with the camera, one or more images of the fundus of the patient, the fundus comprising a plurality of blood vessels; and analyze with the microvascular assessment computing device, the one or more images to determine a microvasculature health index for the patient.

Abstract: A single pole multiple-throw switch for switching an RF signal to one of a plurality of outputs includes coupling the signal to a throw junction, said junction having connected thereto a plurality of switch legs, each leg includes a high voltage shunt diode spaced one quarter-wavelength from the throw junction; each diode mounted at its cathode end to a capacitor and adapted to receive a bias; wherein a controller applies a first DC bias to a selected one of the diodes to cause the selected diode to operate in reverse bias mode, such that the selected diode mounted on the corresponding capacitor provides a low insertion loss to pass the RF signal from the transmission line through the selected leg and to one of the outputs; and applies a second DC bias to the other diodes to cause the other diodes to operate in forward bias mode such that the other diodes mounted onto the corresponding capacitor provides a high insertion loss for blocking the RF signal to the remaining outputs.

Abstract: A single pole multiple-throw switch for switching an RF signal to one of a plurality of outputs includes coupling the signal to a throw junction, said junction having connected thereto a plurality of switch legs, each leg includes a high voltage shunt diode spaced one quarter-wavelength from the throw junction; each diode mounted at its cathode end to a capacitor and adapted to receive a bias; wherein a controller applies a first DC bias to a selected one of the diodes to cause the selected diode to operate in reverse bias mode, such that the selected diode mounted on the corresponding capacitor provides a low insertion loss to pass the RF signal from the transmission line through the selected leg and to one of the outputs; and applies a second DC bias to the other diodes to cause the other diodes to operate in forward bias mode such that the other diodes mounted onto the corresponding capacitor provides a high insertion loss for blocking the RF signal to the remaining outputs.

Abstract: A bidirectional continuously variable phase shifting element is described for incorporation in a monolithic microwave integrated circuit (a circuit which combines both passive and active circuit elements). The preferred active device for use in the phase shifting element is a variable resistance field effect transistor (MESFET), while the preferred passive circuit element is a short transmission line interconnecting the principal electrodes. A variable phase shift for an RF signal passing through the phase shifting element is obtained by adjusting the gate potential of the MESFET between full conduction and nonconduction. The change in conductivity of the MESFET causes the serial impedance of the phase shifting element to vary from a substantially resistive impedance to a substantially capacitively reactive impedance arrangement, which requires only a single active device, is applicable to frequencies generally above 1 GHz, and provides phase shifts up to 45.degree.

Abstract: The inverted microstrip phase shifter consists of a substrate having at least one diode and biasing circuitry connected to one side and at least one center conductor connected to its opposite side. The substrate side containing a center conductor is enclosed within a hollow case so as to form an rf transmission line. The parameters for the biasing circuitry are selected by performing a computer optimization of the chain matrix equivalent expression for the voltage transmission coefficient.