Electromagnetic design of folded‐waveguide resonator filter with single finite‐frequency transmission zero

This article presents electromagnetic (EM) design of a new folded‐waveguide resonator filter that uses an advanced coupling scheme to achieve the desired asymmetric frequency response with an attenuation pole of finite frequency on the high side of the passband. A filter of this type with a fraction bandwidth about 5% at a center frequency of 4.45 GHz has been successfully designed using a commercially available electromagnetic simulator. The designed filter has been fabricated and tested. Simulations and experimental results are presented to validate the design and to show the advantages of this type of filter. This filter also provides a compact size compared with conventional cavity resonator filters. © 2007 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2008.     

High‐yield E‐band diplexer for fixed radio point‐to‐point equipment

The article describes practical guidelines for an E‐Band tuning‐less waveguide diplexer design (71–86 GHz) which requires looser fabrication tolerances and provides higher yield than traditional methods. Physical considerations concerning sensitivity to manufacturing inaccuracies are discussed and proven by designing and manufacturing two different diplexers on a set of typical specifications. © 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:508–512, 2014.     

Output feedback control of a three‐phase four‐wire unified power quality conditioner

The increasing penetration of power electronics in electrical equipment entails a significant impact on the deterioration of power supply quality. In this paper, the problem of power quality is addressed for distorted three‐phase four‐wire power grids supplying non‐linear unbalanced loads. A unified power quality conditioner (UPQC) is considered to ensure satisfactory electrical energy quality. To this end, a UPQC controller is designed to meet four control objectives: i) compensation of the harmonics and the reactive load currents; ii) compensation for the harmonic voltages at the point of common coupling (PCC); iii) cancelation of the neutral current; iv) and regulation of the inverter DC voltage. The control design relies on the UPQC nonlinear model that accounts for the electrical grid line impedance. Unlike previous works, the proposed controller features an output‐feedback nature as it combines a nonlinear regulator, designed with a sliding‐mode technique, and a state observer designed using a Lyapunov stability based technique. The latter provides the former with online estimates of the series filter AC voltages, which are not assumed to be accessible to measurements. The closed loop error system is analyzed using the average stability approach. It turns out that all (tracking and estimation) errors are asymptotically vanishing, except for the DC bus voltage tracking error, which is periodic in steady‐state with an amplitude depending on the (DC bus) capacitor, the larger the capacitor the smaller the steady‐state DC voltage tracking error level. This theoretical result is confirmed by simulations involving wide range variations of the load current.     

CAD of high‐εr microstrip bandpass filters

A simple design procedure is described for miniaturized microstrip bandpass filters on high‐ε_r substrates. Costs and design times are reduced by replacing experimental measurements with EM simulations. The procedure is confirmed through the design of a miniaturized microstrip hairpin‐coupled bandpass filter at 1.8 GHz on BaO? PbO? Nd₂O₃? TiO₂ (ε_r=90.9) ceramic substrate. © 2002 Wiley Periodicals, Inc. Int J RF and Microwave CAE 12: 229–235, 2002.     

Development of a high‐definition 32‐in. PDP

We developed the world's smallest‐profile 32‐in. HDTV PDP. By improving the luminous efficiency, a luminance of 650 cd/m² and power consumption (discharge and driving circuit) of 200 W or less was achieved. Moreover, incorporating an advanced color compensating (ACC) filter improved the PDP's color‐reproduction capability, better than that of CRTs.     

Microwave dual‐band bandstop filter with improved spurious resonance behavior

A design technique to improve the spurious resonance behavior of dual‐band bandstop filters is presented. A compact dual‐band bandstop filter with two stop bands that can be controlled independently with improved passband frequency response is designed. The operational bandwidth of the proposed compact dual‐band bandstop filter is increased by pushing the first spurious resonance from being about twice the resonance frequency to more than three times the resonance frequency. Stepped impedance open loop resonators with substantially increased outer‐edge width are used to improve the spurious resonance response. Both simulation and measured results are presented and good agreement is obtained between the results. The fabricated filter exhibits dual operating frequencies at 1460 MHz and 2640 MHz with 5.5% and 5% stopband fractional bandwidths, respectively. © 2012 Wiley Periodicals, Inc. Int J RF and Microwave CAE 23: 627–633, 2013.     

New approaches to process simplification for large‐area high‐resolution TFT‐LCDs

Abstract— Novel process architectures are proposed for fabricating large‐area high‐resolution TFT‐LCDs with a minimal number of process steps. A low contact resistance between Al bus lines and the transparent conductive oxide layer, necessary for large‐area panels, is obtained by inducing a self‐formed inter‐metallic compound layer at the interface without using any additional buffer or capping layers. For enhanced brightness and resolution, a new TFT array structure integrated on a color‐filter substrate, referred to as an Array on Color Filter (AOC) structure, has been developed. Good‐quality TFTs were successfully constructed on the newly developed color filter for AOC within a sufficiently wide process margin. By adopting these novel technologies, a 15.0‐in. XGA prototype panel was fabricated and shows good display performance. Thus, these novel technologies have improved cost efficiency and productivity for TFT‐LCD manufacturing, and can be applied to the development of TFT‐LCDs of extended display area and enhanced resolution, benefiting from the low resistance bus lines, the high aperture ratio, and reduction in total process steps.     

Dual‐band ridge waveguide filters for high‐selectivity wireless base station applications

Dual‐band filters simplify the system architecture considerably by replacing doubly multiplexed filters. This is especially important in base stations for wireless communications, where high‐selective filtering functions are required, with very stringent requirements in size and insertion losses. For this goal, compact dual‐band filters realized in air‐filled metallic ridge waveguides are proposed. The dual‐band approach shown in this article allows fulfilling the stringent insertion loss specifications of very selective filtering functions. The ridge waveguide resonators are placed in a canonical folded top‐bottom structure layout. Coupling sections that provide cross‐couplings are realized by irises opened in the intermediate wall. Given the high‐order of the dual‐band filter required for actual wireless applications, an efficient modeling by the mode‐matching method is used. A complete challenging filter prototype with 16 poles and 10 transmission zeros with specifications of typical wireless transceivers is built and tested for verification. © 2016 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:703–712, 2016.     

Computer‐aided design of 3D microwave filter using quasi‐planar high Qu dielectric resonator

A dielectric resonator filter is proposed for high‐speed data communication systems and for multilayer filter applications. The structure is composed of a partially metallized dielectric plate enclosed in a parallelepipedic cavity. This topology allows high integration in a planar‐type environment. The proper excitation is ensured by coplanar lines directly integrated on the dielectric resonator. This structure, easily manufactured, is suitable for high frequency‐filtering and power applications. In order to realize two‐ and four‐pole filters without tuning, some new coupling and frequency compensation techniques are presented. To compensate for a parasitic effect, a direct optimization method is combined applying a global electromagnetic (EM) analysis to describe the four‐pole filter. Some experiments are performed to verify the theoretical design. © 2000 John Wiley & Sons, Inc. Int J RF and Microwave CAE 10: 333–341, 2000.     

Efficient analysis of in‐line waveguide filters and frequency‐selective surfaces with stepped holes

This paper presents a novel method for the analysis of large classes of microwave and mm‐wave passive components, including in‐line waveguide filters, single‐ and multi‐layer frequency selective surfaces, and open‐ended waveguide array antennas. This method is based on the segmentation technique, which permits us to reduce complex components to cascaded waveguide step discontinuities, which are separately characterized through their generalized impedance matrices, as calculated by the integral equation (IE) technique and the boundary integral‐resonant mode expansion (BI‐RME) method. Some examples demonstrate the flexibility and efficiency of the IE/BI‐RME method, and its utility in investigating novel structures not requiring costly fabrication techniques. © 2003 Wiley Periodicals, Inc. Int J RF and Microwave CAE 13: 306–315, 2003.     

Bulk acoustic wave‐coupled resonator filters: Concept,design, and application

Bulk‐acoustic‐wave‐coupled resonator filters is an emerging technology that is capable of meeting increasingly ambitious demands of wireless applications by addressing performance, chip size, and die cost. This article outlines the fundamental design principles of these filters. A major consideration of filter design is the choice of the coupling structure between the two vertically stacked resonators. This can be either a multilayer Bragg coupler or a novel structure using a single layer of a very low acoustic impedance material. It is demonstrated how spurious modes are related to the dispersion diagram and how they affect the passband characteristics. For the suppression of these spurious modes suitable edge termination techniques are discussed. Based on optimized coupler performance and known parasitic effects, we analyze circuit design methods for microwave filters and duplexers with specific passband, roll‐off, and wideband responses. We show as example a miniature 2.0 × 1.6 mm² Universal Mobile Telecommunication System (UMTS) Band1 duplexer fabricated using the coupler resonator technology. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2011.     

Continuous‐discrete filters for bearings‐only underwater target tracking problems

In this work, we develop a continuous‐discrete shifted Rayleigh filter (CD‐SRF) and a continuous‐discrete sparse‐grid Gauss‐Hermite filter (CD‐SGHF) for a real‐life passive underwater bearings‐only target tracking problem. The stochastic difference equation describing the process model is derived from its continuous equivalent using Ito‐Taylor expansion of order 1.5. The performance of the proposed filters is compared in terms of root mean square error (RMSE), track divergence and computational time. For a fair comparison, popular filters like the unscented Kalman filter (UKF), cubature Kalman filter (CKF) and Gauss–Hermite filter (GHF) are implemented. The effect of initial uncertainty, measurement noise covariance and sampling time on filtering accuracy is also studied. Finally, RMSEs of all the filters are evaluated in comparison with the Cramer–Rao lower bound (CRLB). From simulation results, it was observed that CD filters performed with higher accuracy than their discrete equivalents, with CD‐SRF proving to be the most accurate among all the filters.     

Thermal transfer for flat‐panel‐display manufacturing

Abstract— Photolithography is currently the predominant patterning method in the flat‐panel‐display (FPD) industry. Thermal lithography is a novel approach offering superior process control, a completely dry process, and considerable cost savings. Thermal imaging is now the dominant imaging method in computer‐to‐plate applications in the printing industry, with over 6000 installations world‐wide. Two applications, in which this technology could be applied in the FPD industry, will be discussed in detail: color filters for liquid‐crystal displays (LCDs) and barrier ribs for LCDs and organic light‐emitting‐diode (OLED) displays.     

Dual‐band dielectric resonator bandstop filters

This article presents the design and implementation of a new asymmetric dual‐band bandstop filter using TE01δ mode dielectric resonator (DR) technology. The coupling matrix is generated by frequency transformation technique applied to advance filtering functions for direct‐coupled asymmetric dual‐band bandstop filter in cul‐de‐sac configuration. The proposed approach provides control of all the major parameters such as center frequencies, intercavity couplings, and input/output couplings of filter independently in both the designated bands. The dual‐band DR filters (2 × 2) pole, with return loss = 15 dB and percentage rejection bandwidth of 1.6 and 0.6% in two bands, at 9.96 and 10.15 GHz, respectively, are designed, built, and tested. The measured and simulated results are in good agreement over the desired band. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:282–288, 2015.     

Two‐zero four‐pole building block for microwave waveguide filters using all‐resonant modes at their cutoff frequency

This article describes a basic building block for microwave waveguide filters. It uses a new coupling scheme where all resonant modes are used at their cutoff frequency. It is composed of a cascade of basic nonloaded rectangular cavities where the modes are alternately single mode and dual mode. These cavities are coupled directly, without any iris. Neither coupling nor tuning screws are needed. The analysis of the discontinuities is performed by the method of moments (MoM). The synthesis makes use of an optimization method based on the genetic algorithm. Prototypes have been realized and measurements are shown to confirm the analysis results. © 2003 Wiley Periodicals, Inc. Int J RF and Microwave CAE 13: 429–437, 2003.     

Computer aided design of H‐plane tapered corrugated waveguide bandpass filters

This paper presents the complete computed aided design approach for the design of H‐plane iris‐coupled bandpass filters with improved stopband performance. Iris‐coupled bandpass filters with mixed (increased and decreased) adjacent resonator widths are proposed for the first time for improvement in the stopband performance. The simulated filter performance shows improved stopband performance and reduced filter dimensions compared with conventional H‐plane uniform corrugated waveguide bandpass filters. ©1999 John Wiley & Sons, Inc. Int J RF and Microwave CAE 9: 14–21, 1999.     

Design and implementation of compact diplexers using dual‐mode cavities

In this paper, the design of compact diplexers with dual‐mode cavities for satellite payloads is detailed. Compact diplexers are composed of coupled resonators without additional waveguide element, leading to a more compact architecture. Two topologies are first implemented and compared with a standard manifold output diplexer, in terms of electrical performances, compactness, and power handling. Hardware prototypes are fabricated and measured for experimental verification. A third topology is finally introduced for the design of noncontiguous diplexers. © 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:249–258, 2014.     

Cost‐effective global surrogate modeling of planar microwave filters using multi‐fidelity bayesian support vector regression

A computationally efficient method is presented for setting up accurate Bayesian support vector regression (BSVR) models of the highly nonlinear |S₂₁| responses of planar microstrip filters using substantially reduced finely discretized training data (compared to traditional design of experiments techniques). Inexpensive coarse‐discretization full‐wave simulations are exploited in conjunction with the sparseness property of BSVR to identify the regions of the input space requiring denser sampling. The proposed technique allows for substantial reduction (by up to 51%) of the computational expense necessary to collect the finely discretized training data, with negligible loss in predictive accuracy. The accuracy of the reduced‐data BSVR models is confirmed by their use within a space mapping optimization algorithm. © 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:11–17, 2014.     

Synthesis of dual‐mode in‐line microwave rectangular filters with higher modes

Satellite communications are used intensively today. Separating the different frequency channels requires high selectivity. Up to now, this high selectivity has been achieved by using circular filters placed in circular waveguides. However, circular waveguides require a complicated design process and are difficult to manufacture. In this article, a filtering method based on rectangular geometry and using the higher mode is presented. The synthesis procedure and its practical equivalent circuit are shown to create independent zeros to the right and/or left of the passband. To validate this new concept of filtering and the corresponding synthesis, applications on TE₁₀/TE₃₀ in‐line rectangular filters are presented. © 2005 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2005.     

Recent advances in microwave active filter design. Part 1: Low‐frequency techniques and noise optimization

This two‐part article presents a representative sample of recent advances in microwave active filter design. In part one, we discuss design techniques based on both analog and digital low‐frequency methods that have been adapted to microwaves. From circuits with analog origins, we present simulated results, with some experimental verification, for a frequency‐dependent negative resistance (FDNR) and active‐inductance MMIC bandpass filters. From circuits with digital origins, we present experimental results for recursive filters, including MMIC bandpass and bandstop structures as well as higher‐order cascaded sections. Part one concludes with a discussion of the noise‐wave formalism and experimental results for active‐recursive and tunable ring‐resonator filters with minimum noise figure. © 2002 Wiley Periodicals, Inc. Int J RF and Microwave CAE 12: 159–176, 2002.