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We demonstrate that a gradual interface between gold and silver supports the propagation of a novel kind of surface electromagnetic wave, which is different from the more well-known surface plasmon polaritons. The existence of such surface waves leads to a paradoxical situation in which a continuous metal barrier which does not have any pinholes may exhibit considerably increased light transmission if the barrier is made of two different metals. A spectroscopic study of this effect is reported. [ABSTRACT FROM AUTHOR]

We construct a synthetic left-handed transmission line with cascaded varactors and shunt inductors. By modulating dc bias, the capacitance of the varactors can be changed and modulation of the output phase state is possible. For frequencies from 4.7 to 6.4 GHz, a very linear phase variation versus voltages of over 200[degrees] phase variation with low insertion-loss variation ([+ or -] 0.5 dB) is demonstrated. This circuit can also act as an efficient harmonic generator when a large signal is applied. Since the left-handed transmission line shows high-pass filter response, harmonics generated are not seriously attenuated. However, because this synthetic transmission line is a very dispersive medium, strong dispersions and instabilities may arise. The circuit size is determined by the diode size and lumped-element inductor, allowing it to be compact. Index Terms--Harmonic generator, left-handed transmission line, phase shifter, varactor.

We combine a right-handed (RH) and a left-handed (LH) nonlinear transmission line (NLTL) to realize a new frequency and phase-tunable bandpass filter (BPF). An RH NLTL is a voltage-controlled low-pass fiter and an LH NLTL is a voltage-controlled high-pass filter, so combining both allows for simultaneous and independent control over the low and high cutoff frequencies of the passband. Also, by using the positive phase propagation of a RH NLTL and the negative phase propagation of an LH NLTL, control over the phase propagation in the passband can be achieved. In the fabricated circuit, the controllable low cutoff frequency is from 480 to 721 MHz and the high cutoff frequency is from 625 to 1005 MHz. Also, we note that whatever the passband is, the phase propagation close to the center frequency is 0[degrees]. Index Terms--Bandpass filters (BPFs), lumped elements, non-linear transmission line (NLTL), phase propagation, transmission line, tunable bandpass filter, varactors.

This paper introduces nonlinear transmission lines based on left-handed (LH) media and simulates harmonic generation and parametric generation in a material that, in two dimensions, could also focus microwaves. This paper discusses physical phenomena that lead to and affect self-supporting harmonic generation and parametric generation in LH nonlinear transmission-line media and outline advantages of these media for developing new types of compact and efficient frequency multipliers and 'active lens' devices. Index Terms--Frequency conversion, left-handed (LH) media, metamaterials, negative refractive index, nonlinear transmission line (NLTL), parametric generation.

We combine a right-handed (RH) and a left-handed (LH) nonlinear transmission line (NLTL) to realize a new frequency and phase-tunable bandpass filter (BPF). An RH NLTL is a voltage-controlled low-pass fiter and an LH NLTL is a voltage-controlled high-pass filter, so combining both allows for simultaneous and independent control over the low and high cutoff frequencies of the passband. Also, by using the positive phase propagation of a RH NLTL and the negative phase propagation of an LH NLTL, control over the phase propagation in the passband can be achieved. In the fabricated circuit, the controllable low cutoff frequency is from 480 to 721 MHz and the high cutoff frequency is from 625 to 1005 MHz. Also, we note that whatever the passband is, the phase propagation close to the center frequency is 0°. [ABSTRACT FROM AUTHOR]