Y.L. Chow

A Low-Profile Frequency Selective Surface With Controllable Triband Characteristics

A novel compact low-profile frequency selective surface (FSS) with controllable triband characteristics is presented. The proposed FSS consists of a stacked periodic array of square loops and complementary apertures, respectively centered within a wire grid and an aperture grid, which can create three transmission poles and two transmission zeros. Controllable triband performance is achieved, allowing the FSS to transmit the signal at 4 GHz while reflecting the signals at 6 and 9.5 GHz. Due to the compact and low-profile structure, the designed FSS has a reduced sensitivity to the incident angle compared to traditional triband FSSs. An equivalent circuit model is proposed for predicting and analyzing the frequency characteristics of this structure. For demonstration, a prototype of the proposed FSS is fabricated and measured. Good agreement between the simulated and measured results is observed.

Simple formula of a patch capacitor on a grounded substrate of two layers

The paper gives a simple CAD formula for a patch on a grounded substrate of two layers by synthetic asymptotes. Similar to the one-layer case, from the derived formula, the equivalent circuit is a fringe capacitor in parallel with an ideal parallel plate capacitor of the two-layer substrate. The average error is less than 3%.

Miniaturized dual-band loaded frequency selective surface with narrow band spacing

In this paper, a novel miniaturized dual-band loaded frequency selective surface (FSS) with narrow band spacing is presented, in which each periodic cell consists of metallic patches connected with lumped inductors and capacitively loaded square loop aperture resonator printed on either side of a dielectric substrate. This structure provides two narrow and closely separated passbands with a distinct null, and an equivalent circuit model is given for analyzing its filter mechanism. The simulated transmission coefficients by CST Microwave Studio (MWS) indicate that the proposed FSS is insensitive to polarization and incident direction of the illuminated wave. A prototype is designed and fabricated for demonstration. Good agreement between the simulated and measured transmission coefficients is obtained, indicating the validity of the proposed design strategies.

Use of a Spatial Field Technique for the Analysis of Active MMICS

The method of moments is applied for the first time to the analysis of active MMICs. A description of the procedure is presented and the analysis of two different amplifier configurations is compared with experimental results. This spatial field technique can be applied to both individual monolithic elements and complex MMICs with the advantage that interelement coupling is automatically taken into account.

Successive SIW (Substrate Integrated Waveguides) types for width reductions by physical reasoning and formulas by analytical (use of) MoM

In this paper, the SIW studied are: beginning from a RWG (regular waveguide of solid walls), to SIW (with sidewalls of vias), then ridged and folded SIWs; for successive narrower waveguide widths. Based on physical reasoning, the analytical formulas derived are accurate with 3 % or less error.

Mixed Spectral/Spatial Domain Moment Method Simulation of Components and Circuits

Electromagnetic simulation of microwave circuits is an emerging technology. In the past it has been possible to analyze small to medium-sized structures on very large computers, but recent developments in method of moment (MoM) techniques and computer workstations have changed this situation. Microwave designers can now simulate entire circuits using standard commercially available tools. A review of the MoM technique being used in EMSimR is presented, along with the basic applications of this tool. Additionally, specific filter and component structures are presented with simulated and measured data.

Broadband Dual-Polarization Microwave Absorber Based on Broadside-Folded Dipole Array With Triangle-Lattice Cells

An improved folded dipole is employed to realize broadband dual-polarization microwave absorber. To further widen the bandwidth, different kinds of lattice cells are considered in the array. It is found that the triangle-lattice cell with equal element spacer would be the best choice. The numerical and measured results show that the relative bandwidth of the absorber surface consisting of triangle cells can reach up to a bandwidth of 112.1% with frequency ratio 3.55 and thickness of 0.22 λ0. The sensitivity to the oblique incidence has been decreased and can be well kept with reflection of -10 dB within the incident angle of 45°.

Investigations on bonding wire array for interconnect of RFICs

In this paper, analytical Moment Method (MoM) is used as one method for analyzing the equivalence between a flat solid rectangular plate and an array of bond wires. In addition, fuzzy Electromagnetism (EM) method is firstly used to derive the formulas of the inductance and capacitance of bonding wire array. To verify the validity and accuracy of proposed formulas for the bonding wire array, several structures with different numbers of bonding wires have been analyzed and simulated. Very good agreements can be found between the simulated S-parameters from the structures and that of the corresponding equivalent circuits. The proposed formulas can be used effectively in the design of practical bonding wire array in internal matching of transistors and IC packaging etc.

Design and Optimization of Stripline Passive Components With Trust-region Aggressive Space Mapping

The optimal design of stripline components with Trust- region Aggressive Space Mapping (TR-ASM) technique is presented in this paper. The field-based equivalent circuit model is implemented as coarse model, while the commercial software IE3D is used as the fine model. Three practical passive components, i.e., two low-pass filters and a power divider are designed and optimized. Good convergence performance is achieved for the designs of all examples.

Inductance calculation of spiral inductors in different shapes

This paper obtains simple shape factors for the inductance calculation of spiral inductors with different shapes. Compared with numerical results (e.g., IE3D), the average error is less than 2%, with a maximum of less than 5%.