Showing papers on "Prototype filter published in 2007"

Microwave Filters for Communication Systems: Fundamentals, Design and Applications

Abstract: Foreword Preface Acknowledgments 1 Radio Frequency (RF) Filter Networks for Wireless Communications-The System Perspective PART I: INTRODUCTION TO A COMMUNICATION SYSTEM, RADIO SPECTRUM, AND INFORMATION PART II: NOISE IN A COMMUNICATION CHANNEL PART III: IMPACT OF SYSTEM DESIGN ON THE REQUIRMENTS OF FILTER NETWORKS 2 Fundamentals of Circuit Theory Approximation 3 Characterization of Lossless Lowpass Prototype filter functions 4 Computer-Aided Synthesis of Characteristic Polynomials 5 Analysis of Multiport Microwave Networks 6 Synthesis of a General Class of the Chebyshev Filter Function 7 Synthesis of Network - Circuit Approach 8 Coupling Matrix Synthesis of Filter Networks 9 Reconfiguration of the Folded Coupling Matrix 10 Synthesis and Application of Extracted Pole and Trisection Elements 11 Microwave Resonators 12 Waveguide and Coaxial Lowpass Filters 13 Waveguide Realization of Single- and Dual-Mode Resonator Filters 14 Design and Physical Realization of Coupled Resonator Filters 15 Advanced EM-Based Design Techniques for Microwave Filters 16 Dielectric Resonator Filters 17 AllPass Phase and Group Delay Equalizer Networks 18 Multiplexer Theory and Design 19 Computer-Aided Diagnosis and Tuning of Microwave Filters 20 High-Power Considerations in Microwave Filter Networks Appendix A Appendix B Appendix C Appendix D Index

Detection is key - Harmonic detection methods for active power filter applications

Abstract: This article gives a survey of the commonly used methods for harmonic detection in active power filters (APFs). The work proposes a simulation setup that decouples the harmonic detection method from the active filter model and its controllers. In this way, the selected methods can be equally analyzed and compared with respect to their performance, which helps in anticipating possible implementation issues. A comparison is given that may be used to decide the future hardware setup implementation. The comparison shows that the choice of numerical filtering is a key factor for obtaining a good accuracy and dynamic performance of an active power filter.

Surface Acoustic Wave Filters: With Applications to Electronic Communications and Signal Processing

Abstract: This book gives the fundamental principles and device design techniques for surface acoustic wave filters. It covers the devices in widespread use today: bandpass and pulse compression filters, correlators and non-linear convolvers and resonators. The newest technologies for low bandpass filters are fully covered such as unidirectional transducers, resonators in impedance element filters, resonators in double-mode surface acoustic wave filters and transverse-coupled resonators using waveguides.The book covers the theory of acoustic wave physics, the piezoelectric effect, electrostatics at a surface, effective permittivity, piezoelectric SAW excitation and reception, and the SAW element factor. These are the main requirements for developing quasi-static theory, which gives a basis for the non-reflective transducers in transversal bandpass filters and interdigital pulse compression filters. It is also needed for the reflective transducers used in the newer devices. It is a thorough revision of a classic on surface acoustic wave filters first published in 1985 and still in print. It uniquely combines easy-to-understand principles with practical design techniques for all the devices in widespread use today. It includes complete coverage of all the latest devices which are key to mobile phones, TVs and radar systems; and, a new foreword by Sir Eric Albert Ash.

Novel Balanced Coupled-Line Bandpass Filters With Common-Mode Noise Suppression

Abstract: Novel balanced coupled-line bandpass filters, using suitable balanced coupled-line sections and quarter-wavelength resonators, are proposed. For design purposes, the differential- and common-mode equivalent half-circuits are established. Based on these circuits, a better balanced filter structure is implemented so that the desired differential-mode response may be realized and the level of common-mode noise may be minimized simultaneously. Besides, a suitable capacitive or inductive cross-coupled effect is introduced so as to create two transmission zeros for improving the filter selectivity; however, it also enhances the signal imbalance and degrades the common-mode rejection. In this study, various second- and fourth-order balanced filters are implemented to discuss the associated differential-mode responses and the signal-imbalance phenomena resulted from the cross-coupled effect. Specifically, the fourth-order filter with a common-mode rejection ratio of 40 dB within the passband is demonstrated and examined

A Microstrip Ultra-Wideband Bandpass Filter With Cascaded Broadband Bandpass and Bandstop Filters

Abstract: This paper develops a novel ultra-wideband bandpass filter by cascading a broadband bandpass filter with another broadband bandstop filter. Properly selected impedances of transmission lines achieve broadband bandpass and bandstop filters and make independent designs possible. Detailed design and synthesis procedures are provided; moreover, agreement between measured and theoretically predicted results demonstrates feasibility of the proposed filter. Due to its simple structure, the ultra-wideband bandpass filter newly introduced in this paper is suitable for integration in the single-chipped circuit or implementation on printed circuit boards.

A Synthesis Method for Dual-Passband Microwave Filters

Abstract: This paper describes a synthesis method for symmetric dual-passband microwave filters. The proposed method employs frequency transformation techniques for finding the locations of poles and zeros of a desired filter. This method can be used to design dual-passband filters with prescribed passbands and attenuation at stopbands directly without the need for any optimization processes. To validate the procedure a dual-passband stripline filter is designed and fabricated. The stripline dual-passband filter is designed with passbands at 3.90-3.95 and 4.05-4.10 GHz, and 30-dB attenuation at the stopband. This measured results show a good agreement with the theoretical ones. The frequency transformation for symmetric dual-passband filters is also extended to include asymmetric dual-passband responses. This flexible frequency transformation preserves the attenuation characteristics of the low-pass filter prototype. Examples are shown to discuss the flexibility of this transformation.

Stopband-Extended Balanced Bandpass Filter Using Coupled Stepped-Impedance Resonators

Abstract: A novel fourth-order balanced bandpass filter is proposed based on the half-wavelength (lambda/2) stepped-impedance resonators (SIRs). By properly adjusting the parameters of each SIR, the proposed filter may be made compact and its stopband may also be extended simultaneously. Specifically, a balanced filter with acceptable common-mode rejection is implemented with its differential-mode and common-mode stopbands extended up to 5.5 fo d, where fo d is the center frequency of differential-mode passband.

Electronic Filter Simulation & Design

Abstract: Chapter 1. Basic Concepts Chapter 2. Lumped Passive Filters Chapter 3. Active RC Filters Chapter 4. Transmission Lines Chapter 5. Low-Pass and Band-Stop Distributed Filters Chapter 6. High-Pass and Band-Pass Distributed Filters Chapter 7. Special Designs of High Frequency Filters Chapter 8. Discrete Time Filters Chapter 9. Waveguide Filters Appendix A: Calculation of the Polynomial Coefficients from a Factorized Expression Appendix B: Reflection Coefficients Zeroes of a Polynomial All-Pole Low-Pass Filter Appendix C: Complementarity of the Singly Terminated Low-Pass and High-Pass Filters with the Same Cutoff Frequency, Order, and Load Resistance Index

Design of Frequency Invariant Beamformers for Broadband Arrays

Abstract: A simple method for the design of a class of arrays with frequency invariant beam patterns is proposed. Starting from the desired frequency invariant beam pattern of an n-D array, the proposed method uses a series of substitutions and an n-D inverse Fourier transform to obtain the desired frequency responses of the filters following each sensor. Given their desired frequency responses, these filters can be realized by either an analogue filter or a digital filter. Hence the proposed method can cover the design of broadband arrays with either analogue signals or discrete signals. Two design examples are provided, with one for a linear array and one for a planar array.

Narrow-band microwave filter design

Abstract: In this article, Dishal's concepts, EM simulation, and the port-tuning concept are combined as a powerful procedure for narrow-band filter design. When applied to an EM-based filter prototype, port tuning gives a direct indication of the magnitude and direction of the tunings needed to correct coupling errors and resonator frequency errors. An EM-based filter prototype potentially captures all the physics of the real hardware and includes second-order effects that may be impossible to describe using analytical models. After iteratively reducing all the errors in the EM-based prototype, the first hardware prototype that was built will meet performance goals. This design methodology can be applied to simple all-pole Chebyshev filters and to more complex cross-coupled filters that place transmission zeros in the stopbands.

Wideband Bandstop Filter With Cross-Coupling

Abstract: A general circuit configuration for cross-coupled wideband bandstop filters is proposed. The distinct filtering characteristics of this new type of transmission line filter are investigated theoretically and experimentally. It is shown that a ripple stopband can be created, leading to a quasi-elliptic function response that enhances the rejection bandwidth. A demonstrator with approximately 80% fractional bandwidth at a mid-stopband frequency of 4 GHz is developed and presented. The proposed filter is successfully realized in theory and verified by full-wave electromagnetic simulation and the experiment. Theoretical, simulated, and measured results are in excellent agreement.

Miniature Dual-Mode Microstrip Filters

Abstract: In order to reduce the size of dual-mode microstrip filters by keeping excellent performance, novel filter geometry is proposed. The novel filter includes a dual-mode resonator based on a meander structure. The effect of input/output feed lines located along a straight line on filter response is investigated for the dual-mode filter. The coupling between degenerate modes of the proposed dual-mode microstrip resonator is discussed depending on the perturbation size. The two dual-mode microstrip bandpass filters with real axis and imaginary axis transmission zeros (TZs) are designed, fabricated, and measured to document the validity of the description of the positive and negative coupling coefficient

Hankel transform filters for dipole antenna radiation in a conductive medium

Abstract: We discuss the Hankel transforms related to a particular application, i.e. the dipole antenna radiation in conductive media, such as the antenna radiation in sea‐bed electromagnetic applications. In this application, the electromagnetic wavefields decay very rapidly with distance. A good filter means that it can be used to evaluate weak fields. Exponential sampling transforms a Hankel transform into a convolution equation, which must be solved to obtain the filter coefficients. Here, we use a direct matrix inversion method to solve the convolution equation in the sample domain, instead of the Fourier transform method and the Wiener–Hopf method, previously used to solve the convolution equation. This direct method is conceptually simple and is suitable for our optimization process: by using the Sommerfeld identity, we search for the optimum sampling interval, which corresponds to the minimum wavefield, evaluated for a given length filter. The performances of the new filters obtained are compared with some well‐known filters. We find that our filters perform better for our application; that is, for the same length filters, our filters are able to calculate weaker fields. For users working in similar applications, three sets of filters with lengths 61, 121, 241 are available from the author.

A Compact Square Loop Dual-Mode Bandpass Filter with Wide Stop-Band

Abstract: A new dual-mode microstrip bandpass filter with wide stop-band is presented using the square loop resonator with treeshaped patches attached to the four inner corners of the loop. The mode splitting is realized by introducing a small cut locating at a 45◦ offset from its two orthogonal modes. It is shown that the dual-mode filter has a wide stop-band including the first spurious resonance frequency. The center frequency can be tuned. Moreover, the proposed filter has a smaller size compared with conventional dualmode bandpass filters at the same central frequency.

Fractional Delay Filter Design Based on Truncated Lagrange Interpolation

Abstract: A new design method for fractional delay filters based on truncating the impulse response of the Lagrange interpolation filter is presented. The truncated Lagrange fractional delay filter introduces a wider approximation bandwidth than the Lagrange filter. However, because of truncation, a ripple caused by the Gibbs phenomenon appears in the filter's frequency response. Proper choices of filter order and prototype filter order allow adjusting the overshoot to a desired level and simultaneously reducing the overall frequency-response error. The design of the proposed filter is computationally efficient, because it is based on polynomial formulas, which have common terms for all coefficients.

Fully Integrated High-Q Switched Capacitor Bandpass Filter with Center Frequency and Bandwidth Tuning

Abstract: This paper proposes to study the design of a novel high-Q fully integrated switched capacitor bandpass filter. This circuit, implemented in CMOS technology, allows a tunable high selectivity over a broad frequency band. The proposed architecture is intended to replace passive surface acoustic wave (SAW) filters in low-cost wireless radio-communication applications. To show the feasibility of the proposed filter a prototype has been fabricated and tested. Measurements show quality factors up to 300, and a tunable center frequency range of 290 MHz [240 - 530 MHz] with a bandwidth tuning.

Integrated Bandpass Filter at 77 GHz in SiGe Technology

Abstract: The implementation and characterization of an integrated passive bandpass filter at 77GHz is presented. A lumped elements filter occupying very small die area (110times60mum2, without pads) is demonstrated. It is realized with spiral inductors and metal-insulator-metal capacitors. The filter is fabricated in an advanced SiGe:C technology. It has a center frequency of 77.3GHz and a bandwidth of 12GHz. The insertion loss is 6.4dB. This is the first time that integrated inductors are used for filters at millimeter wave frequencies around 80GHz

A Low-Power Programmable Bandpass Filter Section for Higher Order Filter Applications

Abstract: We present a programmable, continuous-time bandpass filter that is extremely compact, power efficient, and can cover a wide range of frequencies (10 Hz-10 MHz). This capacitively coupled current conveyor (C 4) has a second-order bandpass transfer function and is capable of being used as a basic bandpass-filter element to create high-order filters. The use of floating-gate transistors helps to ease the difficulties of effectively utilizing G m-C filters by providing precise, programmable current sources that set the filter's time constants. Additionally, we provide an algorithmic design approach for constructing these bandpass filters to meet any given specifications. This bandpass filter is ideally suited to large filter-bank applications because of its small size and low-power demands.

Compact Tunable Bandstop Filter Integrated with Large Deflected Actuators

Abstract: This paper presents a novel approach to construct a low cost, compact tunable bandstop filter. The tunability is achieved with the use of thermal actuators and square plates as tuning elements to change the loading effect of slot resonators etched in the ground plane. A unique fabrication process is developed to allow monolithic integration of tuning elements and the bandstop filter on the same substrate. A 3-pole tunable bandstop filter is designed, fabricated and tested. The experimental filter has a center frequency of 6 GHz and a 20 dB rejection bandwidth close to 0.8 GHz. The measured result for the 3-pole tunable bandstop filter reveals that the proposed filter can be continuously tuned over a range of 500 MHz.

Parameterized filters and signaling techniques

Abstract: Filter taps for filters are specified by filter coefficient parameters. The filter taps are greater in number than the coefficient parameters from which the filter taps are calculated. For example, two coefficient parameters are used to specify a four-tap filter. Filter information can be signaled in a bitstream, such as by signaling one or more family parameters for a filter family and, for each filter in a family, signaling one or more filter tap parameters from which filter taps can be derived. Family parameters can include a number of filters parameter, a resolution parameter, a scaling bits parameter, and/or a full integer position filter present parameter that indicates whether or not the filters include an integer position filter. Filter parameters can be signaled and used to determine coefficient parameters from which filter taps are calculated.

High output impedance current-mode universal filter employing dual-output current-controlled conveyors and grounded capacitors

Abstract: A novel current-controlled two-input three-output current-mode universal filter, which employs only three dual-output controlled-controlled current conveyors (DOCCCIIs) and two grounded capacitors, is presented in this paper. The proposed configuration provides inverting-type lowpass, noninverting-type lowpass, inverting-type bandpass, noninverting-type bandpass, highpass, bandstop and allpass current responses at a high impedance terminal, which enable easy cascadability. The filter also offers an independent electronic control of the natural frequency ω o and the parameter ω o / Q through adjusting the bias current of the DOCCCII. No critical matching condition is required for realizing all the filter responses, and all the incremental parameter sensitivities are low. The performances of the proposed circuit are simulated with PSPICE to confirm the presented theory.

Passband filters for terahertz radiation based on dual metallic photonic structures

Abstract: This paper reports on the development of two-dimensional metallic microstructures for the filtering of terahertz radiation. These structures are fabricated using ultraviolet-based processing of thick SU8 resist. This micromachining technique enables the array patterns, dimensions, and consequently the filter characteristics to be readily defined. In particular, we demonstrate that a filter with an isolated near-square-shaped passband can be realized on the basis of a combination of two different metallic photonic arrays of optimized design.

Dual Bandstop Filter With Enhanced Upper Passband Response

Abstract: A dual bandstop filter affects frequencies in a lower passband, first and second stopbands separated by a middle passband, and an upper passband. The filter includes two legs. In one version, one leg is a highpass filter while the other leg is a bandstop filter outputting into a lowpass filter. In a second version, one leg is a lowpass filter while the other leg is highpass filter outputting into a bandstop filter. The first version is preferred when the upper value of the lower passband is around 100 MHz or less, while the second version is preferred when the upper value of the lower passband is around 100 MHz or more. In a third version, one leg is a highpass filter while the other leg is a bandstop filter sandwiched between two lowpass filters, preventing second resonances from the lowpass filter from interfering with desired frequencies in the upper passband.

An $L_1$ -Method for the Design of Linear-Phase FIR Digital Filters

Abstract: This paper considers the design of linear-phase finite impulse response digital filters using an L1 optimality criterion. The motivation for using such filters as well as a mathematical framework for their design is introduced. It is shown that L1 filters possess flat passbands and stopbands while keeping the transition band comparable to that of least-squares filters. The uniqueness of L1-based filters is explored, and an alternation type theorem for the optimal frequency response is derived. An efficient algorithm for calculating the optimal filter coefficients is proposed, which may be viewed as the analogue of the celebrated Remez exchange method. A comparison with other design techniques is made, demonstrating that the L1 approach may be a good alternative in several applications.

The Coupling Matrix in Low-Pass Prototype Filters

Abstract: This article was intended to give a sense of the versatility of the coupling matrix representation in the normalized coupled-resonator low-pass prototype. Although it is a theoretical model only, it is widely used as the starting point for most microwave band-pass filter designs using coupled resonators

Microwave filter design from a systems perspective

Abstract: The intention of this article is merely to provide the reader with some basic concepts that will enable them to better make intelligent decisions when specifying filters. We restrict the discussion to the most common type of filter, the bandpass filter. Bandpass filters are intended to minimize the signal attenuation in one band of frequencies (the passband), while achieving a specified attenuation in another band (the stopband).

Planar Realization of a Triple-Mode Bandpass Filter Using a Multilayer Configuration

Abstract: A triple-mode bandpass filter has been designed using a multilayer approach. The filter topology consists of a square loop resonator located inside a resonant cavity. The walls of the cavity were designed using periodic metal vias that connect the top and bottom ground planes for an overall planar configuration. A filter prototype was fabricated and measured, producing a fully canonical filtering function with three resonant poles and three transmission zeros. The filter yielded an insertion loss of 1.1 dB at the passband centered at 5.8 GHz

Recursive Anisotropic 2-D Gaussian Filtering Based on a Triple-Axis Decomposition

Abstract: We describe a recursive algorithm for anisotropic 2-D Gaussian filtering, based on separating the filter into the cascade of three, rather two, 1-D filters The filters operate along axes obtained by integer horizontal and/or vertical pixel shifts This eliminates interpolation, which removes spatial inhomogeneity in the filter, and produces more elliptically shaped kernels It also results in a more regular filter structure, which facilitates implementation in DSP chips Finally, it improves matching between filters with the same eccentricity and width, but different orientations Our analysis and experiments indicate that the computational complexity is similar to an algorithm that operates along two axes ( <11ms for a 512times512 image using a 32-GHz Pentium 4 PC) On the other hand, given a limited set of basis filter axes, there is an orientation dependent lower bound on the achievable aspect ratios

On Two-Channel Filter Banks With Directional Vanishing Moments

Abstract: The contourlet transform was proposed to address the limited directional resolution of the separable wavelet transform One way to guarantee good approximation behavior is to let the directional filters in the contourlet filter bank have sharp frequency response This requires filters with large support size We seek to isolate the key filter property that ensures good approximation In this direction, we propose filters with directional vanishing moments (DVM) These filters, we show, annihilate information along a given direction We study two-channel filter banks with DVM filters We provide conditions under which the design of DVM filter banks is possible A complete characterization of the product filter is, thus, obtained We propose a design framework that avoids 2-D factorization using the mapping technique The filters designed, when used in the contourlet transform, exhibit nonlinear approximation comparable to the conventional filters while being shorter and, therefore, providing better visual quality with less ringing artifacts Furthermore, experiments show that the proposed filters outperform the conventional ones in image approximation and denoising