Nonlinear resonant structures consisting of coupled ring resonators can be modeled by difference-differential equations that take into account non-instantaneous Kerr response and the effect of loss. We present a simple and efficient numerical formalism for solution of the system and calculation of the time evolution. The technique is demonstrated by investigating the dynamical behavior of the coupled structure with two rings, namely, focusing on self-pulsing solutions. The influence of both, loss and non-instantaneous Kerr response, is also presented.
the design allows the antenna to be fed on both short sides, which makes possible to use the same antenna with one manufacture tooling only to satisfy both directions of the feeding-cable routing to the Wi-Fi module on the back of the TV. In addition, the shielding portion of the antenna also relaxes the effects of the back metal casing when the antenna is placed in a thin LCD TV. The stand-alone antenna in free space yields peak gain of about 2.9 dBi in the 2.4 GHz band and in the range of 4.1 to 5.3 dBi in the 5.2/5.8 GHz with radiation efficiency exceeding 84% over the bands. The antenna in a 42-inch, widescreen LCD TV with four possible cases was analyzed. The results show that the achievable impedance bandwidth covers the 2.4/5.2/5.8 bands. That is, the proposed design is much less affected by the back metal casing for the slim LCD display. The variation of radiation efficiency among four cases is within 0.5 dB. The antenna gain is the largest in Case 1, where the antenna was put on the left side, on the edge of the top wall with the signal feeding relatively close to the free space.ABSTRACT: This article presents a frequency-reconfigurable printed inverted-F antenna for terrestrial broadcast applications. To reconfigure the operating frequency, PIN diodes and variable capacitor diodes are used in this antenna structure. To expand its operating frequency bandwidth, two inverted-F radiators are integrated on the same printed circuit board. Simulation and measurement results show the operating frequencies can be controlled with the junction capacitance or the reversed-bias voltage of varicaps. The far-field radiation patterns shows that they are nearly omnidirectional within the reconfigurable frequency band.
We demonstrate a finite-difference scheme for solution of nonlinear coupled evolution equations that describe propagation of optical pulses under the slowly-varying envelope approximation. The technique is used for modelling of Kerr-nonlinear structures which involve microring resonators and exhibit optical bistability and self-pulsing. The results suggest that the technique may be considered as a useful counterpart of the established methods, such as the transfer matrix method or finite-difference time-domain method.
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