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The TM 0 surface mode in an infinitely long parallel-plate waveguide filled with a double-positive (DPS) and epsilon-negative (ENG) metamaterial bi-layer is studied. With proper constitutive parameters and thicknesses of the two layers, the slow-wave factor (SWF) for such a parallel-plate waveguide can tend to infinity as the frequency decreases. A 2-D cavity based on the DPS-ENG bi- layer waveguide is constructed and studied to evaluate the radiation ability of its corresponding patch antenna. Based on the cavity model analysis of patch antennas, we show that good efficiency for broadside radiation of such a cavity-based rectangular patch antenna can be achieved when one layer of the cavity is shielded (or partially shielded) by PEC boundaries. Taking practical loss and dispersion into consideration, a miniaturized cavity-based rectangular patch antenna is proposed as an example. With the super-slow TM 0 surface mode excited in the bi-layer by a simple coaxial line feeding, the antenna has a dimension of only 0.107γ0 0 x 0.129γ0 x 0.045γ0. The patch antenna produces broadside radiation, and fairly good radiation efficiency is achieved. The PEC-Partially-Shielded-ENG-Cavity based rectangular patch antenna with a further miniaturization but reduced radiation efficiency is also discussed. [ABSTRACT FROM AUTHOR]

A compact H-shaped defected ground structure (DGS) is applied to reduce the mutual coupling between array elements and eliminate the scan blindness in a microstrip phased array design. The proposed DGS is inserted between the adjacent E-plane coupled elements in the array to suppress the pronounced surface waves. A two-element array is measured and the results show that a reduction in mutual coupling of 12 dB is obtained between elements at the operation frequency of the array. The scan properties of microstrip phased arrays with and without DGS are studied by the waveguide simulator method. The analysis indicates that the scan blindness of the microstrip phased array can be well eliminated because of the effect of the proposed DGS. Meanwhile, the active patterns of the array centre element in 7×3 element arrays with and without the H-shaped DGS are simulated, and the results agree with those obtained by the waveguide simulator method. [ABSTRACT FROM AUTHOR]

In this paper, a memory-reduced (MR) 2-D order-marching time-domain (OMTD) method for uniform waveguides is proposed. The OMTD method uses weighted Laguerre polynomials and Galerkin's testing procedure to eliminate the temporal variables and results in an unconditionally stable scheme. Although the OMTD method may be more efficient than the finite-difference time-domain (FDTD) method with too many time steps to complete a simulation, it has to deal with matrix inversion. To reduce its high computer memory requirements and computational power when analyzing complicated geometries, the divergence theorem is introduced to obtain a more memory-efficient matrix equation. Two waveguide examples are presented to validate the accuracy and efficiency of our algorithm. [ABSTRACT FROM AUTHOR]

An accurate model of composite right/left handed transmission line (CRLH-TL) is used to design an arbitrary dual-band branch-line coupler (BLC). A pure left handed (LH) cell is not possible due to unavoidable parasitic series inductance and shunt capacitance effects, which are taken into consideration in the accurate model. With respect to a dual-band BLC designed with a conventional model, the coupler designed with the accurate model uses less chip components and achieves perfect performance, which is demonstrated by simulation and measurement results. [ABSTRACT FROM AUTHOR]

A coplanar waveguide-fed uniplanar multi-folded slot antenna that has impedance bandwidth enough to cover UWB systems is presented. The -10 dB return loss bandwidth of the antenna spans from about 3 GHz to about 11 GHz. Parametric study is presented. Details of the proposed ultra-wideband design are described and simulation results are presented and discussed in this paper. [ABSTRACT FROM AUTHOR]

A novel partly shielded-finite ground coplanar waveguide (PS-FGCPW) low pass filter has been designed. The device consists of a PS-FGCPW loaded with metal stubs at periodic positions of the signal line. The width of the metal stubs has a sinusoidal variation as the function of the position along the signal line. By properly choosing the position and dimension of the loaded stubs, a wide stop band, more than four times the pass bandwidth, is obtained through the suppression of spurious frequencies inherent to the distributed structures. The prototype also exhibits very sharp cutoff, very low insertion loss in the passband, slow-wave effect and high isolation performance. [ABSTRACT FROM AUTHOR]

A compact slow-wave microstrip rat-race ring coupler is presented. The new structure effectively reduces the occupied area to 8% of the conventional rat-race ring coupler due to the slow-wave effect. The design is validated both by using the full-wave electromagnetic simulator and by measurement. [ABSTRACT FROM AUTHOR]