Читать книгу Introduction To Modern Planar Transmission Lines - Anand K. Verma - Страница 237

The EM‐wave propagating through a normal DPS slab provides the lagging phase of the propagating part of the field at the output end of the slab. It is noted that the nonpropagating decaying evanescent wave also exists, along with the propagating wavefield components, inside the slab. However, for a propagating wave, the DNG slab provides the leading phase at its output. The increasing evanescent wave exists inside a DNG slab, along with the propagating wavefield components. Thus, the DNG slab can act both as (i) a phase‐compensator and (ii) as an amplitude‐compensator, i.e. as a field amplifier, without any power amplification. The field amplifier is like a voltage step‐up transformer without any power amplification. The first property, in the form of the DGS‐DNG composite slab, is helpful in the design of compact sub‐wavelength resonator [J.12, B.6]. A normal DPS resonator is half‐wavelength long. The second property offers an opportunity to design subwavelength resolution superlens [J.2, J.13–J.21]. This subsection explains both properties of a DNG slab. The superlens is discussed briefly in the next subsection.

Figure 5.11 EM‐wave propagation through the DNG and composite DPS‐DNG slabs.