Abstract: A sensor device includes an optical limiting structure including a metal layer with at least one metal particle having a size no greater than about 1500 nanometers, and a phase-change material layer disposed adjacent at least a portion of the metal layer, the phase-change material layer including a phase-change material, and a dendritic-metal layer disposed over at least a portion of the phase-change material layer of the optical limiting structure, the dendritic-metal layer including an organic compound including branching chain amino acid groups attached to a metal structure. The optical limiting structure is configured to transition from a first optical state to a second optical state when the phase-change material is heated above a critical temperature, with transmittance of light at a predetermined wavelength through the optical limiting structure being lower at the second optical state of the optical limiting structure in relation to the first optical state of the optical limiting structure.

Abstract: A method and apparatus is provided for remotely and constantly calibrating a transponder by using the ring around phenomenon. A number of different time varying physical quantities, such as for example temperature, signal level, noise, transmission line flex, frequency, and general operational effects, affect the inherent delay in transponders on a time varying basis. The invention relies on a the ring around phenomenon to produce pulse doublets, wherein the distance between the pulses in the pulse doublets correspond to the instantaneous delay in the transponder. The system is configured so that instantaneous variation in the transmission delay is detected and recognized on a pulse by pulse basis and transmitted to the interrogation device, which then functions to calculate the actual delay. Normal operation of the transponder is not affected by the continuous calibration method, and therefore a special calibration mode is not required.

Abstract: A method and apparatus for transponding pulsed RF signals is provided. The method comprises receiving, with a receiver, pulsed RF signals having a plurality of PRIs. Further the method includes generating, with a PRI tracker, control signals from the received pulsed RF signals. The method then filters the received pulsed RF signals with the control signals to thereby obtain enable signals, which in turn control a transmitter permitting retransmission without clock jitter.