In this paper, a formulation for obliquely incident electromagnetic wave has been presented for an analysis of high-power electromagnetic pulse penetration into multilayer dispersive media. Based on generalized models of measured dielectric constants and propagation channels reflecting the Earth's general features, the propagation phenomenon of the obliquely incident early-time (E1) high-altitude electromagnetic pulse (HEMP) is analyzed in frequency as well as in time domains. In addition, the polarization and critical angle are also considered. It is found that the total reflection occurs at an incident angle of about 38 • at the soil-rock interface, and that the parallel-polarized E1 HEMP penetrates better than the perpendicular-polarized one. The peak level of the penetrating electric field is found to be 5.6 kV/m at normal incidence, regardless of the type of polarization, and 1.1 kV/m for incidence at 30 • in perpendicular case.

Surface dielectric barrier discharge (SDBD), which is widely used to control turbulence in aerodynamics, has a significant effect on the radar cross-section (RCS). A four-way linearly synthesized SDBD air plasma actuator is designed to bolster the plasma effects on electromagnetic waves. The diffraction angle is calculated to predict the RCS because of the periodic structure of staggered electrodes. The simplified plasma modeling is utilized to calculate the inhomogeneous surface plasma distribution. Monostatic RCS shows the diffraction in the plane perpendicular to the electrode array and the notable distortion by plasma. In comparison, the overall pattern is maintained in the parallel plane with minor plasma effects. The trends also appear in the bistatic RCS, which has a significant difference in the observation plane perpendicular to the electrodes. The peaks by Bragg's diffraction are shown, and the RCS is reduced by 10 dB in a certain range by the plasma effect. The diffraction caused by the actuator and the inhomogeneous air plasma should be considered in designing an SDBD actuator for a wide range of application.

signed RLC network will bring side effects, i.e., a worse S 22 around the cut-off frequency, as shown in Figure 6. A trade-off in design should be made between a wider bandwidth and a decent stability.To further demonstrate the amplifier bandwidth improvement from series RLC network, a common-emitter amplifier and a common-collector followed by a common-emitter amplifier are designed for a complete comparison. The measured S 21 parameters are plotted in Figure 7. For the sake of fair comparison, all amplifiers are biased at the same collector current. Input and output ports are terminated with 50 ⍀. From Figure 7, a much wider bandwidth is achieved in amplifier with the RLC network. CONCLUSIONSA bandwidth improvement network incorporated with a gain compensation technique is proposed for HBT amplifiers. The network consists of a small value of inductor at base of Q3, in series with a decoupling capacitance and a resistance to improve high frequency stability. The network cannot only be implemented in a common-collector following by a cascode amplifier, but also in a traveling wave matching (TWM) amplifier, a distributed amplifier (DA), and a matrix amplifier (MA) [5][6][7][8][9]. The network has been demonstrated to improve the bandwidths of various amplifiers.