To overcome these constraints, this work proposes a preliminary and broadband

wave impedance equalization of the two guiding geometries, ridged and rectangular, by adjusting the design parameters M and D shown in Fig.

The mechanical properties of the fillings affect the discontinuity degree of the specimen, which was measured by the

wave impedance. The

wave impedances of four media are shown in Table 2 [21-24], where [rho] is the density, c is the longitudinal wave velocity, [eta] is the

wave impedance, and [DELTA][eta] is the

wave impedance difference value.

The test system consists of a launcher, a punch, an entrance rod (density: 7.810 g/[cm.sup.3], elastic wave velocity: 5410 m/s, and

wave impedance: 4.23 x 107kg x [m.sup.-2] x [s.sup.-1]), and transmissive rod, etc.

Moreover, for a complete ballistic performance evaluation, both the shock

wave impedance and the maximum bullet speed (limit velocity) to withstand by new composites are needed.

where [GAMMA] is the reflection coefficient, [Z.sub.n] is the

wave impedance in the MA material, and [[eta].sub.o] is the

wave impedance in air.

Its impedance is [Z.sub.T] = [Z.sub.0]/[square root of [[epsilon].sub.r]], where [Z.sub.0] = 377 [OMEGA] is the

wave impedance in free space and [[epsilon].sub.r] is the relative permittivity of the dielectric substrate.

Denote the variable

wave impedance ratio to describe the nonuniform degree of pile segment; that is, [R.sub.v] represents the ratio of

wave impedance of normal pile segment to that of nonuniform pile segment.

This is because, with the increase of the elasticity modulus of the foam concrete, its

wave impedance and

wave impedance ratio both increase.

In this case method of moments (MoM) for calculation of the

wave impedance and effective permittivity in case of odd- and even- excitation [Z.sub.e], [Z.sub.o], [[epsilon].sub.e] and [[epsilon].sub.o] is used.

In (2), k is the complex propagation constant of a particular mode along the periodic grating structure, and ko and no represent the wave number and

wave impedance in free-space.

where [Z.sub.1] = [square root of [[mu].sub.1]/[[epsilon].sub.1]] is the characteristic

wave impedance of the coating; [Z.sub.2] = [square root of [[mu].sub.2]/[[epsilon].sub.2]] is the characteristic

wave impedance of the material under the coating; [k.sub.1] = [omega] [square root of [[epsilon].sub.1][[mu].sub.1]] is the wave number inside the coating; [[theta].sub.1] and [[theta].sub.2] are angle of transmission in the coating and conductor, respectively; d is thickness of the coating.

We then take into account the boundary effects due to the excess polarization and magnetization induced at the interface, which are approximated by electric and magnetic susceptibilities, to derive the equation that extracts the effective

wave impedance of a metamaterial for the case of a wave impinging obliquely on a metamaterial slab.