Z. B. Ye

A Miniaturized and Low Insertion Loss LTCC Filter with Two Finite Transmission Zeros for Bluetooth Application

This letter outlines the design and manufacture of a miniaturized bandpass filter realized by low-temperature cofired ceramic (LTCC) technology for bluetooth applications. The bandpass filter with a central frequency of 2450 MHz and a 100 MHz passband is designed as a three-dimensional (3-D) structure based on lumped components. Experimental measurements were compared with modeling. The insertion losses in the passband (100 MHz) were less than 1.2 dB and the attenuation was more than 20 dB in the stop band. The area occupied by the filter is 1.6times0.8times0.6 mm3.

A miniaturized LTCC bandpass filter with low insertion loss and high image rejection within 6.5 to 7.1GHz frequency range

A low-temperature-cofired ceramic (LTCC) bandpass filter with low insertion loss and high image rejection is presented for super heterodyne microwave receiver within 6.5–7.1GHz band. By improving the filter cell structure, two transmission zeros can be generated to achieve wide-band image suppression from cascading filter cells. The presented method provides the design flexibility of locating these transmission zeros distributed in the lower and upper stopbands. To reduce insertion loss and size of the filter, a miniaturized LTCC three-stage bandpass filter with two transmission zeros in lower stopband has been implemented for experimental demonstration. The measured insertion loss is less than 1.0 dB at 6.8GHz, the measured image rejection from 5 to 5.6GHz is more than 42dB, the input/output VSWR is less than 1.5. The size of the miniaturized filter is only 2.5mm×2mm×1.2mm. The process yield of the LTCC filter is more than 90%.

A miniaturized wideband complementary LTCC diplexer based on transmission lines and lumped elements

This paper presented a design and simulation result of a miniaturized complementary diplexer realized by low-temperature co-fired ceramic (LTCC) technology. The diplexer consisted of two pass-bands, a central frequency of 1.175GHz with bandwidth of 46.8% and a central frequency of 1.925GHz with bandwidth of 28.6% respectively. In the presented structure, we used transmission lines to realize the characteristics of lower pass-band, while lumped circular inductors were adopted to achieve the requirements of upper pass-band. The interaction of the two filters was handled very well by using a complementary schematic. We managed to make the VSWR on the antenna port less than 1.7. The final three-dimensional model occupied a volume of 3.2×2.5×1.95-mm.

Analysis of finite periodic structure by FDTD and SOC technique

In this paper, the application of the finite-difference time-domain (FDTD) algorithm combined with the short-open calibration SOC technique to three-dimensional finite periodic structure is presented. We can get the scattering parameters of the whole periodic structure through analyzing only one cell of it. So the combination of the SOC technique and FDTD for finite periodic structures makes the calculation much faster and much more accurate. Results for finite periodic structure are well compared with the conventional FDTD method.

FDTD time series extrapolation by the least squares support vector machine method with the particle swarm optimization technique

A new combination of particle swarm optimization (PSO) and least-squares support vector machines (LS-SVM) technique for FDTD time series forecasting is presented. In this paper, the PSO is extended to optimize the hyperparameter used in the LS-SVM algorithm. Numerical simulations demonstrate that the PSO method can efficiently get the optimal value of the hyperparameter used in the LS-SVM algorithm. And the PSO/spl I.bar/LS-SVM method can improve the computational efficiency of the FDTD algorithm when compared with the direct FDTD method.

Mass lumping techniques combined with 3D Time-domain Finite-element Method for the vector wave equation

Two mass lumping techniques are applied to time-domain finite-element method (TDFEM) based on the vector wave equation in order to avoid solving sparse linear system at each time step. One is the Lacoste method and the other is a new technique based on local affine coordinate system while considering constant fields in an element. Cavity structures are simulated. And the comparison of the two mass lumping techniques and the conventional TDFEM (without mass lumping) are presented. The numerical results show that the new mass lumping technique is better than the Lacoste method.

A Miniaturized P-Band Coupler with Multi-Layer Dielectric and High Performance

This paper presents a new compact 90deg hybrid coupler using multi-layer technology. In order to reduce an intrinsic circuit area of the hybrid coupler, a compact meandered line configuration and a new multi-layer structure design have been adopted. The configuration and structural dimensions of the multi-layer structure were designed and investigated through detailed 3-D electro-magnetic simulations. The measured insertion loss is less than 0.4 dB, and the phase imbalance is less than 3 degree with the frequency range from 380 MHz to 520 MHz. The overall dimension is as small as 16.5 mm times 12.2 mm times 1.66 mm.

Transient analysis of IMPATT oscillator with extended spectral-element time-domain method

The microwave IMPATT oscillator is analyzed by a hybrid electromagnetic-circuit simulator, which is based on the spectral-element time domain (SETD) method. In the space of electromagnetic, the IMPATT diode is substituted by a one-port equivalent circuit. At each time step, the change of current on diode will influence the field around it, and vice versa. For the extended SETD method, the solver is fully explicit, so the CPU time can be significantly reduced. A simple numerical result demonstrates the ability and effectiveness of the extended SETD method for the fast analysis of microwave IMPATT Oscillator.

Analysis of transient electromagnetic scattering using spectral-element time-domain method

A spectral-element time-domain method is presented to solve the problems of transient electromagnetic scattering. It has the advantages of spectral accuracy and block-diagonal mass matrix. This technique is based on Gauss-Lobatto-Legendre polynomials and Galerkins method is used for spatial discretization. The perfectly matched layer is employed to truncate the boundary in unbounded problems. Active Frequency selective surface is analyzed in the last part and numerical results demonstrate the accuracy of the method.

Time-Domain Analysis of Photonic Band Gap Structure by a Finite-Element Tearing and Interconnecting Algorithm

Based on the finite element approximation and nonoverlapping domain decomposition, an efficient parallel algorithm of the finite-element time-domain method is presented for the analysis of the photonic band gap structure. The unconditionally stable implicit Newmark-beta scheme is used in the time domain finite-element tearing and interconnecting algorithm. Through the use of Lagrange multipliers, the field continuity is enforced explicitly along the edges shared by more than two subdomains and implicitly at the interfaces between two subdomains. In this way, the direct sparse solver is used for each subdomain system and the large global problem is reduced to a much smaller interface problem. Thus, the final system matrix equation is solved by Krylov subspace solvers and a Neumann boundary condition is obtained at the interfaces between all the subdomains. Therefore, the fields inside each subdomain are then calculated by this Neumann boundary condition. Numerical results demonstrate that our proposed method is extremely efficient for the analysis of the photonic band gap structures.