Dapeng Wang

Leakage and ohmic losses investigation in substrate‐integrated waveguide

[1]xa0Rectangular waveguide (RW) with sidewalls of vertical conducting cylinders (i.e., substrate-integrated waveguide, SIW) becomes popular with the advent of low-temperature cofired ceramic (LTCC) structure. The formula of leakage loss through the SIW with small cylinders has been found, based on the surface impedance of cylinder walls derived from an analytical MoM. To complete the study of loss, the ohmic loss in the SIW is investigated also in this paper. The theoretical formulas show good agreements with numerical HFSS simulations and the measured data from hardware experiments, demonstrating potential applications to the research and design of some interesting devices such as leaky antennas, etc.

Characteristics of H-Plane Rectangular Waveguide Bends Integrated into Thin Substrate

In multilayer microwave integrated circuits such as low-temperature co-fired ceramics (LTCCs) or multilayer printed circuit boards (PCBs), waveguide-like structures can be fabricated in planar form by using periodic metallic via holes called substrate integrated rectangular waveguides (SIRWs) [1]-[2]. The SIRW structures can largely preserve the well-known advantages of conventional rectangular waveguides; it is useful for the design of millimeter-wave circuits such as filters, resonators, and antennas etc.

Fast analysis of microwave integrated circuits using preconditioned SMCG method

The analysis and design of planar structures such as microwave monolithic integrated circuits (MMIC) has become a very important topic. Full-wave electromagnetic analysis of microstrip structures is especially significant. Due to the complexity of this scheme, efficient numerical tools are required for their analysis. For these arbitrarily-shaped planar structures, a mixed-potential integral equation (MPIE) formulation with RWG triangular discretization is solved by the method of moments (MoM). One of the most popular techniques for analyzing this scheme is the sparse-matrix/canonical grid (SMCG) method. The impedance matrix of the SMCG method can be decomposed into near-interaction and far-interaction portions. During the iterative process, the near-interaction portion of the matrix-vector multiplication is computed directly as the conventional MPIE formulation. The far-interaction portion of the matrix-vector multiplication is achieved by a Taylor series expansion of the Greens function about the grid point of a uniformly-spaced canonical grid overlaying the triangular discretization (Chan, C.H. et al., 1992). We propose two preconditioned schemes for accelerating iteration of the SMCG method. One method is the inner-outer flexible generalized minimal residual (FGMRES), the other is the approximate inverse of near-interaction.

The propagation characteristics of double-layer substrate integrated waveguide (SIW) structure

The propagation characteristics of double-layer SIW structures have been investigated in this paper. Based on the theory of resonance cavity and SIW, the simple theoretical formulas for the lower and upper frequencies in the passband have been found. The theoretical analyses have indicated these two frequencies have much dependence on the width of SIW and the length of the coupling slot. Agreement between the simulation data and the calculated results from the formulas can be observed.