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Showing papers on "Prototype filter published in 2005"


Proceedings ArticleDOI
12 Jun 2005
TL;DR: In this paper, a composite microstrip bandpass filter (BPF) with a 3 dB fractional bandwidth of more than 100% was designed for ultra wideband (UWB) wireless communications.
Abstract: A new technique is developed for designing a composite microstrip bandpass filter (BPF) with a 3 dB fractional bandwidth of more than 100%. The BPF is suitable for ultra-wideband (UWB) wireless communications. The design utilizes embedding individually designed highpass structures and lowpass filters (LPF) into each other, followed by an optimization for tuning in-band performance. The stepped-impedance LPF is employed to attenuate the upper stopband and quarter-wave short-circuited stubs are used to realize the lower stopband. Two such BPFs are fabricated and measured to demonstrate the performance.

311 citations


Journal ArticleDOI
13 Jun 2005
TL;DR: In this article, the authors demonstrate the potential of sub-wavelength resonators, namely, split-ring resonators and complementary split ring resonators to suppress undesired spurious bands in microwave filters, a key aspect to improve their rejection bandwidths.
Abstract: The main aim of this paper is to demonstrate the potentiality of sub-wavelength resonators, namely, split-ring resonators, complementary split-ring resonators, and related structures to the suppression of undesired spurious bands in microwave filters, a key aspect to improve their rejection bandwidths. The main relevant characteristics of the cited resonators are their dimensions (which can be much smaller than signal wavelength at resonance) and their high-Q factor. This allows us to design stopband structures with significant rejection levels, few stages, and small dimensions, which can be integrated within the filter active region. By this means, no extra area is added to the device, while the passband of interest is virtually unaltered. A wide variety of bandpass filters, implemented in both coplanar-waveguide and microstrip technologies, have been designed and fabricated by the authors. The characterization of these devices points out the efficiency of the proposed approach to improve filter responses with harmonic rejection levels near 40 dB in some cases. It is also important to highlight that the conventional design methodology for the filters holds. For certain configurations, the presence of the resonators slightly lowers the phase velocity at the frequencies of interest with the added advantage of some level of reduction in device dimensions.

217 citations


Book
05 Oct 2005
TL;DR: The z Transform Method Revisited, a model from Other Models, and a solution using MATLAB Functions to Solve Difference Equations Using the Classical Method are presented.
Abstract: Preface. 1. Introduction. 1.1 Introduction. 1.2 Application of DSP. 1.3 Discrete-Time Signals. 1.4 History of Filter Design. 1.5 Analog and Digital Signal Processing. 1.6 Summary. Problems. References. 2. Time-Domain Analysis and z Transform. 2.1 A Linear, Time-Invariant System. 2.2 z Transform Theory. 2.3 Using z Transform to Solve Difference Equations. 2.4 Solving Difference Equations Using the Classical Method. 2.5 z Transform Method Revisited. 2.6 Convolution Revisited. 2.7 A Model from Other Models. 2.8 Stability. 2.9 Solution Using MATLAB Functions. 2.10 Summary. Problems. References. 3. Frequency-Domain Analysis. 3.1 Introduction. 3.2 Theory of Sampling. 3.3 DTFT and IDTFT. 3.4 DTFT of Unit Step Sequence. 3.5 Use of MATLAB to Compute DTFT. 3.6 DTFS and DFT. 3.7 Fast Fourier Transform. 3.8 Use of MATLAB to Compute DFT and IDFT. 3.9 Summary/ Problems. References. 4. Infinite Impulse Response Filters. 4.1 Introduction. 4.2 Magnitude Approximation of Analog Filters. 4.3 Analog Frequency Transformations. 4.4 Digital Filters. 4.5 Impulse-Invariant Transformation. 4.6 Bilinear Transformation. 4.7 Digital Spectral Transformation. 4.8 Allpass Filters. 4.9 IIR Filter Design Using MATLAB. 4.10 Yule-Walker Approximation. 4.11 Summary. Problems. References. 5. Finite Impulse Response Filters. 5.1 Introduction. 5.2 Linear Phase Fir Filters. 5.3 Fourier Series Method Modified by Windows. 5.4 Design of Windowed FIR Filter Using MATLAB. 5.5 Equiripple Linear Phase FIR Filters. 5.6 Design of Equiripple FIR Filters Using MATLAB. 5.7 Frequency Sampling Method. 5.8 Summary. Problems. References. 6. Filter Realizations. 6.1 Introduction. 6.2 FIR Filter Realizations. 6.3 IIR Filter Realizations. 6.4 Allpass Filters in Parallel. 6.5 Realization of FIR and IIR Filters Using MATLAB. 6.6 Summary. Problems. References. 7. Quantized Filter Analysis. 7.1 Introduction. 7.2 Filter Design-Analysis Tool. 7.3 Quantized Filter Analysis. 7.4 Binary Numbers and Arithmetic. 7.5 Quantization Analysis of IIR Filters. 7.6 Quantization Analyis of FIR Filters. 7.7 Summary. Problems. References. 8. Hardware Design Using DSP Chips. 8.1 Introduction. 8.2 Simulink and Real-Time Workshop. 8.3 Design Preliminaries. 8.4 Code Generation. 8.5 Code Composer Studio. 8.6 Simulator and Emulator. 8.7 Conclusion. References. 9. MATLAB Primer. 9.1 Introduction. 9.2 Signal Processing Toolbox. References. Index.

197 citations


Journal ArticleDOI
TL;DR: In this paper, a bandpass filter design method for suppressing spurious responses in the stopband by choosing the constitutive resonators with the same fundamental frequency, but staggered higher order resonant frequencies is proposed.
Abstract: This paper proposes a bandpass filter design method for suppressing spurious responses in the stopband by choosing the constitutive resonators with the same fundamental frequency, but staggered higher order resonant frequencies. The design concept is demonstrated by a four-pole parallel-coupled Chebyshev bandpass filter and a compact four-pole cross-coupled elliptic-type bandpass filter. Each filter is composed of four different stepped-impedance resonators (SIRs) for which a general design guideline has been provided in order to have the same fundamental frequency and different spurious frequencies by proper adjusting the impedance and length ratios of the SIR. Being based on knowledge of the coupling coefficients and following the traditional design procedure, the resultant filter structures are simple and easy to synthesize. The measured results are in good agreement with the simulated predictions, showing that better than -30-dB rejection levels in the stopband up to 5.4f/sub 0/ and 8.2f/sub 0/ are achieved by the Chebyshev and quasi-elliptic filters, respectively.

189 citations


Journal ArticleDOI
TL;DR: In this paper, a novel one-section bandstop filter (BSF) was proposed and fabricated by using single quarterwavelength resonator with one section of anti-coupled lines with short circuits at one end.
Abstract: A novel one-section bandstop filter (BSF), which possesses the characteristics of compact size, wide bandwidth, and low insertion loss is proposed and fabricated. This bandstop filter was constructed by using single quarter-wavelength resonator with one section of anti-coupled lines with short circuits at one end. The attenuation-pole characteristics of this type of bandstop filters are investigated through TEM transmission-line model. Design procedures are clearly presented. The 3-dB bandwidth of the first stopband and insertion loss of the first passband of this BSF is from 2.3 GHz to 9.5 GHz and below 0.3 dB, respectively. There is good agreement between the simulated and experimental results.

168 citations


Journal ArticleDOI
07 Nov 2005
TL;DR: In this article, the authors present new ideas for the design and implementation of microwave filters with single and dual stopbands, which can be realized with waveguide, coaxial, dielectric resonators, or in a planar technology.
Abstract: This paper presents new ideas for the design and implementation of microwave filters with single and dual stopbands. They can be realized with waveguide, coaxial, dielectric resonators, or in a planar technology. The new methods represent an advance over present methods in that the resonators are direct coupled, thus avoiding the need for transmission line phase lengths between resonator stubs that tend to degrade performance due to their dispersion and are difficult to adjust during tuning. Three bandstop (BS) configurations are presented. The first will accommodate even or odd characteristics and also asymmetric responses, although some negative or diagonal cross-couplings will be needed. The second resembles the cul-de-sac configuration for bandpass filters and needs no diagonal or negative couplings even for asymmetric characteristics. The third is an application of the cul-de-sac synthesis technique to dual-band bandstop (DBBS) filters. All these BS designs are very similar to regular bandpass filters in their design and realization. The design of a DBBS filter is presented and compared with an equivalent bandpass filter to demonstrate its advantages. Finally, the simulated and measured results of a fourth-degree BS filter design in the novel cul-de-sac configuration are presented.

141 citations


Proceedings ArticleDOI
01 Jan 2005
TL;DR: In this article, two types of suspended stripline ultra-wideband bandpass filters are described, one based on a standard lumped element (L-C) filter concept including transmission zeroes to improve the upper passband slope, and another consisting of the combination of a low-pass and a high-pass filter.
Abstract: Two types of suspended stripline ultra-wideband bandpass filters are described, one based on a standard lumped element (L-C) filter concept including transmission zeroes to improve the upper passband slope, and a second one consisting of the combination of a low-pass and a high-pass filter.

132 citations


Proceedings ArticleDOI
12 Jun 2005
TL;DR: A corresponding varactor-tuned microstrip absorptive bandstop filter is described and its unique ability to maintain its attenuation while tuning across a broad frequency range using only resonant frequency tuning is demonstrated.
Abstract: Two absorptive bandstop filter circuit topologies are introduced. The preferred topology is analyzed and its advantages over traditional approaches quantified. A corresponding varactor-tuned microstrip absorptive bandstop filter is described and its unique ability to maintain its attenuation while tuning across a broad frequency range using only resonant frequency tuning is demonstrated.

128 citations


Journal ArticleDOI
TL;DR: In this paper, an all-optical bandpass microwave filter is implemented using an electrooptic phase modulator combined with a dispersive device to eliminate the baseband resonance of a typical low-pass filter.
Abstract: Theoretical analysis and experimental implementation of an all-optical bandpass microwave filter are presented. Bandpass filtering is implemented using an electrooptic phase modulator combined with a dispersive device to eliminate the baseband resonance of a typical low-pass filter. In addition to bandpass operation, the proposed filter also provides an improved mainlobe-to-sidelobe ratio (MSR) and a reduced mainlobe bandwidth compared with those of the conventional microwave filters with windowing. A four-tap bandpass microwave filter with a 3-dB mainlobe bandwidth of 2.65 GHz and an MSR of 30 dB is demonstrated. The filter performances, including the reconfigurability, tunability, and the dynamic range, are also discussed.

111 citations


Journal ArticleDOI
TL;DR: In this paper, a second-order bandpass filter of serial configuration was proposed, which incorporates a grounding capacitor, connecting the two conventional parallel LC resonators with the ground, to provide two finite transmission zeros.
Abstract: This study proposes a second-order bandpass filter of serial configuration. The filter schema incorporates a grounding capacitor, connecting the two conventional parallel LC resonators with the ground, to provide two finite transmission zeros. The impedance matrix and graphical solutions describe proposed filter's operation principle. To demonstrate the proposed filter schema, two bandpass filters, with center frequencies of 2.44 and 4.8 GHz, were designed and implemented using low-temperature co-fired ceramic multilayer technology. The measured results were found to agree well with the simulation results. The 2.44-GHz fabricated bandpass filter was found to possess low in-band insertion loss and high out-band suppression, making it suitable in wireless local area networks, Bluetooth, and RF home links.

81 citations


Journal ArticleDOI
TL;DR: In this paper, a novel meandered parallel coupled-line structure is proposed to suppress the first spurious passband of a microstrip bandpass filter, which can equalize the modal transmission phases at any interested frequency due to its dispersive response.
Abstract: A novel meandered parallel coupled-line structure is proposed to suppress the first spurious passband of a microstrip bandpass filter. The meandered parallel coupled line can equalize the modal transmission phases at any interested frequency such as first spurious passband frequency due to its dispersive response. Several filters are designed and fabricated on a substrate with a dielectric constant of 10.2 and a thickness of 50 mil (1.27 mm) to demonstrate the validity of the proposed method. The example filters are chosen to be of large fractional bandwidth and with a relatively high dielectric-constant substrate where, in these cases, the first spurious passband near twice of the passband frequency (2fo) seriously degrades the conventional parallel coupled filter's upper stopband performance. The upper stopband performance of the proposed filters drastically improves that the measured first spurious passband are suppressed to better than -50 dB for all example filters. Besides, a meandered coupled line not only suppresses the filter's first passband, but also largely shrinks its length. The characteristics of the proposed structure and the design procedures of the filter are described in detail

Journal ArticleDOI
TL;DR: In this paper, a novel miniaturized parallel coupled-line bandpass filter with suppression of second and third harmonic frequencies is demonstrated, based on the capacitive termination on the conventional parallel coupled line to achieve size minimization, while the spurious responses are eliminated by the overcoupling approach.
Abstract: A novel miniaturized parallel coupled-line bandpass filter with suppression of second and third harmonic frequencies is demonstrated in this paper. This new filter is based on the capacitive termination on the conventional parallel coupled line to achieve size minimization, while the spurious responses are eliminated by the over-coupling approach. These features offer the classical parallel coupled-line bandpass filter simultaneous compactness and wide stopband performance. The simulations and measurements of a 900-MHz prototype bandpass filter are presented. The measured results agree well with the simulation. Compared with the conventional parallel coupled-line bandpass filter, the measured second and third spurious responses are suppressed to -64 and -55 dB, respectively. In addition, the circuitry size of the prototype filter can be reduced up to 25%.

Proceedings ArticleDOI
04 Dec 2005
TL;DR: Highly selective microstrip bandpass filters for UWB applications are proposed, by using the optimum distributed highpass filter structure of 11th-order to achieve a wide bandwidth from 3.1 to 10.6GHz as well as good selectivity.
Abstract: Highly selective microstrip bandpass filters for UWB applications are proposed, by using the optimum distributed highpass filter structure of 11th-order to achieve a wide bandwidth from 31 to 106GHz as well as good selectivity In addition, suitable filter layout is adopted to reduce the filter size and the number of vias required Specifically, two compact 11th-order UWB microstrip bandpass filters with good selectivity are implemented and carefully examined

Journal ArticleDOI
TL;DR: In this paper, a thin-film optical filter used as a one-dimensional spatial filter is presented, and its design is briefly examined, which consists of a stack of quarter-wave dielectric layers upon a right-angle prism that selectively cancel a reflected or transmitted plane-wave front for various angles of incidence.
Abstract: A thin-film optical filter used as a one-dimensional spatial filter is presented, and its design is briefly examined. The filter consists of a stack of quarter-wave dielectric layers upon a right-angle prism that selectively cancel a reflected or transmitted plane-wave front for various angles of incidence. Transmittance and reflectance are low-pass functions or high-pass functions of the angle of incidence with a high degree of steepness. In combination, these filters exhibit bandpass transmittance with a variable bandwidth. Applications to detection of extrasolar planets are briefly discussed.

Journal ArticleDOI
TL;DR: In this paper, a new class of E-plane filters based on cross-coupled resonators or over-moded cavities is introduced, which exhibit pseudoelliptic transfer functions with steep attenuation slopes.
Abstract: A new class of E-plane filters based on cross-coupled resonators or over-moded cavities is introduced. The filters exhibit pseudoelliptic transfer functions with steep attenuation slopes. The metal inserts and separating wall between waveguide sections can be fabricated using electro-deposition techniques with the accuracy required for millimeter-wave applications. The filters are mass-producible, are much shorter than traditional E-plane filters, and have less insertion loss. Based on this new type of E-plane filter, highly compact diplexer structures are designed. A comparison between prototype filters and design prediction shows excellent agreement.

Journal ArticleDOI
TL;DR: In this article, the authors reported the operation of band-stop filters in the terahertz (THz) frequency range, working at a center frequency of 600GHz.
Abstract: We report the operation of band-stop filters in the terahertz (THz) frequency range, working at a center frequency of 600GHz. The filters were characterized by embedding them in a microstrip line attached to photoconductive switches which act as THz emitters and detectors. The filters have applications in sensing and detection. The chosen filter design allows cascading of several filters along the same microstrip line, which is of particular importance for a proposed molecular sensing array.

Journal ArticleDOI
TL;DR: It has been shown that under certain circumstances, i.e., in a receiver, it is possible to allow microwave filters to have significant passband insertion loss.
Abstract: In this article, it has been shown that under certain circumstances, i.e., in a receiver, it is possible to allow microwave filters to have significant passband insertion loss. Systems analysis of various receiver configurations shows that acceptable noise figures and intercept points may be obtained in receivers containing lossy filters, i.e., ones with low-Q resonators. Thus, the engineering problem is how to develop design techniques for filters that have low-Q resonators, but with acceptable response in terms of selectivity and pass-band flatness. A review of several techniques for bandpass and bandstop filters is presented.

Journal ArticleDOI
17 Jan 2005
TL;DR: In this paper, a new physical realization of an elliptic function filter response is proposed for achieving compact size, wide bandwidth, wide spurious free stopband and high selectivity performance.
Abstract: A new physical realization of an elliptic function filter response is proposed for achieving compact size, wide bandwidth, wide spurious free stopband and high-selectivity performance. The filter configuration can be implemented in conventional waveguide technology or embedded in a multilayer low-temperature co-fired ceramic structure for integration with other circuitry in a chip module. The filter is analyzed using rigorous mode matching. To validate the concept, prototypes of four- and six-cavity elliptic filters are designed following a systematic procedure. Approximate synthesis is used to obtain initial dimensions of the filter and the desired optimum response is obtained by means of a final full-wave optimization. The results are verified with other numerical methods and with the measurements of a fourth-order waveguide filter.

Journal ArticleDOI
TL;DR: The relation between the frequencies in a mesh filter and the geometric measures of user-selected features is explored and a second order filter that can act as lowpass, bandpass, highpass, notch, and band exaggeration/reduction filters is developed.
Abstract: When designing a lowpass filter to eliminate noise in a triangle mesh, the cutoff frequency is typically chosen by a cumbersome trial-and-error process. Therefore, it is important to provide a guideline in selectingfilter frequencies. Here, we explore the relation between the frequencies in a mesh filter and the geometric measures of user-selected features. In addition, by combining previously proposed implicit and explicit formulations, we develop a second order filter that can act as lowpass, bandpass, highpass, notch, and band exaggeration/reduction filters. The proposed GeoFilter framework allows the user to choose the frequencies for that filter based on the physical size of a blob (ellipsoid) automatically fit to a user-selected feature in the mesh. For example, the size of a bump in a noisy pattern can be used as a cutoff frequency in a lowpass filter, while the size of a nose may be used to smoothen a face or to exaggerate its features as in a caricature.

Journal ArticleDOI
TL;DR: In this paper, a general methodology for the design of higher order coupled resonator filters in photonic crystals (PCs) is presented, where the coupling between resonators is treated as though it occurs through a waveguide with an arbitrary phase shift.
Abstract: In this paper, a general methodology for the design of higher order coupled resonator filters in photonic crystals (PCs) is presented. In the proposed approach, the coupling between resonators is treated as though it occurs through a waveguide with an arbitrary phase shift. The coupling through the waveguide is analyzed theoretically, based on the coupled-mode theory in time. The derived theoretical model suggests a way to extend an equivalent circuit approach, previously demonstrated with a certain value of a phase shift, to the higher order filter design with an arbitrary phase shift. The validity of the proposed approach is confirmed by the design of a third-order Chebyshev filter having a center frequency of 193.55 THz, a flat bandwidth of 50 GHz, and ripples of 0.3 dB in the passband. The characteristics of the designed filter are suitable for wavelength-division-multiplexed (WDM) optical communication systems with a 100-GHz channel spacing. The performance of the designed filter is numerically calculated using the two-dimensional (2-D) finite-difference time-domain (FDTD) method.

Proceedings ArticleDOI
12 Jun 2005
TL;DR: In this article, the authors describe progress towards building a 6-15 GHz tunable bandpass filter bank, which consists of three banks of tunable high-pass and low-pass filters.
Abstract: Capacitive RF MEMS switches can be used to adaptively tune microwave filter elements for use in communications and radar. This work describes progress towards building a 6-15 GHz tunable bandpass filter bank. Three banks of tunable high-pass and low-pass filters covering 6-15 GHz were designed and tested. The low-pass filters showed loss ranging from 2 to 4 dB with rejection better than 60 dB. The high-pass filter showed insertion losses ranging from 3 to 5 dB with similar rejection. These filters were cascaded in series in three banks to obtain a tunable bandwidth/center frequency bandpass filter that covers 6-15 GHz.

Journal ArticleDOI
TL;DR: In this paper, the authors used two different ferromagnetic materials, Fe and NiFe, in a microstrip geometry for a local bandpass filter and showed that the center frequency of the filter can be tuned over a wide range by adjusting the magnitude of the bias magnetic field.
Abstract: This paper presents results for a compact, local bandpass filter. We fabricated the filter using two different ferromagnetic materials, Fe and NiFe, in a microstrip geometry. The different values of saturation magnetization of the two ferromagnets give rise to different gyromagnetic resonance frequencies and provide a local bandpass region between them. The results show that the center frequency of the filter can be tuned over a wide range by adjusting the magnitude of the bias magnetic field. The filter’s bandwidth is almost constant (3.5±0.5GHz) over the entire tuning frequency range (6–26GHz). Theoretical calculations are in good agreement with the experimental results.

Journal ArticleDOI
TL;DR: In this paper, a parallel-coupled line filter with broad stopband response is introduced, which is based on the synthesis of bandpass prototypes with pre-defined upper stopband characteristics.
Abstract: A new class of parallel-coupled line filters with broad stopband response is introduced. The design is based on the synthesis of bandpass prototypes with pre-defined upper stopband characteristics. The new filters have uniform- and stepped-impedance resonators, some of which are loaded by open-circuited stubs at their open-circuited ends. A seventh-order filter implementation is presented with a fundamental passband centered at 1 GHz. The measured wide-band transmission characteristic of the filter demonstrated a broad upper stopband and was in agreement with simulations. The performance of the new filter is also compared with the characteristic of a conventionally designed filter to highlight the advantages of the proposed design method.

Journal ArticleDOI
TL;DR: In this article, the design and performance of an active ripple filter using a novel Rogowski-coil current sensor is discussed in detail, and quantitative comparisons are made between a hybrid passive/active filter and a purely passive filter.
Abstract: An active ripple filter is an electronic circuit that cancels or suppresses the ripple current and electromagnetic interference generated by the power stage of a power converter, thus reducing the passive filtration requirements. This paper explores the design of feedforward active ripple filters for current ripple cancellation, including the design tradeoffs, advantages, and limitations of different implementation methods. The design and performance of an active filter using a novel Rogowski-coil current sensor is discussed in detail. Experimental results from a prototype converter system using this approach are presented, and quantitative comparisons are made between a hybrid passive/active filter and a purely passive filter. It is demonstrated that substantial improvements in filter mass and converter transient performance are achievable using this active ripple filtering method.

Journal ArticleDOI
TL;DR: In this article, a new technique for the synthesis of the extended coupling matrix for the Chebyshev filtering function of general kind is presented, which formulates the synthesis as a least square problem involving the eigenvalues of the N+2 transversal coupling matrix and its principal submatrices.
Abstract: A new, quickly converging, technique for the synthesis of the extended coupling matrix for the Chebyshev filtering function of general kind is presented. The method formulates the synthesis as a least squares problem involving the eigenvalues of the N+2 transversal coupling matrix and its principal submatrices.

Journal ArticleDOI
TL;DR: In this paper, a compact parallel-coupled microstrip bandpass filter was proposed by using additional lumped inductors to realize K-inverters between coupled-line sections to achieve an equivalent to the quarter-wavelength (/spl lambda//4) resonator filters.
Abstract: Novel compact parallel-coupled microstrip bandpass filters are proposed by using additional lumped inductors to realize K-inverters between coupled-line sections to achieve an equivalent to the quarter-wavelength (/spl lambda//4) resonator filters. As a result, the filter order can be doubled without increasing the circuit area, and no repeated passband is observed at twice the center frequency. In addition, by introducing the cross-coupling effect, two transmission zeros at upper and lower stopbands may be created. Simple equivalent-circuit models are also established as effective design tools. Specifically, several compact fourth-order microstrip bandpass filters with good stopband rejection are implemented and carefully examined.

Journal ArticleDOI
TL;DR: In this paper, the authors presented the design and microfabrication of a coaxial dual model filter for applications in LMDS systems, which is formed by five conductive layers, each of which is of 700 µm thickness.
Abstract: This paper presents the design and microfabrication of a coaxial dual model filter for applications in LMDS systems. The coaxial structure is formed by five conductive layers, each of which is of 700 µm thickness. The filter uses an air filled coaxial transmission line. It is compact with low dispersion and low loss. The design has been extensively tested using a prototype filter micromachined using laser drilling on a copper sheet and the results show a good agreement with the theoretical calculations. The laser fabrication has exposed weakness in suitability to volume production, uneven edges and oxide residuals on the edges, which affects the filter performance. A process for fabrication of such a filter in SU-8 has been developed which is based on a UV lithographical process. In order to fabricate such thick SU-8 layers, the SU-8 process has been optimized in terms of UV radiation and post exposure baking. During the test fabrication, the optimized SU-8 process has produced microstructures with an aspect ratio of 40:1 and a sidewall of 90 ± 0.1 ◦ . The high quality SU-8 structures can be then either coated with a conductive metal or used as moulds for producing copper structures using an electroforming process. The microfabrication process presented in this paper suits the proposed filter well. It also reveals a good potential for volume production of high quality RF devices. (Some figures in this article are in colour only in the electronic version)

Journal ArticleDOI
TL;DR: In this article, a hybrid compensation system consisting of an active filter and distributed passive filters is presented, where each individual filter is connected to a distortion source and designed to eliminate main harmonics and supply reactive power for the distortion source, while the active filter is responsible for the correction of the system unbalance and the cancellation of the remaining harmonics.
Abstract: This paper presents a hybrid compensation system consisting of an active filter and distributed passive filters In the system, each individual passive filter is connected to a distortion source and designed to eliminate main harmonics and supply reactive power for the distortion source, while the active filter is responsible for the correction of the system unbalance and the cancellation of the remaining harmonics The paper also analyzes the effects of the circuit configuration on the system impedance characteristics and consequently the effectiveness of the filter system Simulation studies are performed for a power system including the dispersed generation units connected into the system through power electronic converters and diode rectifier loads, which produce the distorted waveforms The simulation results have demonstrated that good compensation effects can be achieved by using the combined filter system consisting of distributed passive filters and an active filter

Patent
06 Jun 2005
TL;DR: In this paper, an absorptive bandstop filter includes at least two frequency-dependent networks, one of which constitutes a bandpass filter, that form at least 2 forward signal paths between an input port and an output port and whose transmission magnitude and phase characteristics are selected to provide a relative stopband bandwidth that is substantially independent of the maximum attenuation within the stopband and/or in which the maximum extent of attenuation in the passband is substantially dependent on the unloaded quality factor of the resonators.
Abstract: An absorptive bandstop filter includes at least two frequency-dependent networks, one of which constitutes a bandpass filter, that form at least two forward signal paths between an input port and an output port and whose transmission magnitude and phase characteristics are selected to provide a relative stopband bandwidth that is substantially independent of the maximum attenuation within the stopband and/or in which the maximum attenuation within the stopband is substantially independent of the unloaded quality factor of the resonators. The constituent network characteristics can also be selected to provide low reflection in the stopband as well as in the passband. The absorptive bandstop filter can be electrically tunable and can substantially maintain its attenuation characteristics over a broad frequency tuning range.

Proceedings ArticleDOI
12 Jun 2005
TL;DR: In this article, a new class of dual-mode microstrip filters based on triangular dualmode loop resonators is presented, which allows simultaneous edge coupling to the two dual-modes from a single feed (microstrip).
Abstract: The paper presents a new class of dual-mode microstrip filters based on triangular dual-mode microstrip loop resonators. The triangular shape of the loop eases the design of dual-mode filters by allowing simultaneous edge coupling to the two dual-modes from a single feed (microstrip). Two consecutive dual-mode loop resonators are also edge coupled to each other without changing the triangular shape of the resonators. Dual-mode pseudo-elliptic bandpass filters of orders two and four are designed and presented.