Abstract
In this paper, a numerical method has been proposed for the analysis of highlydispersive
linear and non-linear metamaterial structures. Initially, pulse propagation
along non-linear composite right/left-handed transmission line (CRLH TL) has been
carefully studied. For this purpose, a dispersive CRLH line has been loaded with hyper
abrupt diodes to achieve non-linearity. The characteristic impedance and propagation
constant of each unit cell of the CRLH TL is then varied at each time-step, and the nonuniform
line is analyzed. A novel interpolation scheme, based on the smooth behaviour
of the propagation constant with small variations of the shunt capacitor has been
proposed. This scheme has provided an 80% reduction of the computational cost
maintaining high accuracy. A general example which combines dispersion and nonlinearity
has finally been presented, validated and discussed. Secondly, the impulseregime
radiation of a leaky-wave antenna has been analyzed and employed to describe a
real-time spectrogram analyzer (RTSA). A calibration method for the system, which
takes into account the directivity variation of the antenna with frequency, has been
introduced. Numerical results have shown that the proposed technique provides an
extremely fast and accurate tool to characterize leaky-wave based RTSA systems.
This work was partially supported by the Spanish Ministry of Education and Science
under Grant FPU-AP2006-015 and with the Project TEC2007-67630-C03-02.