Showing papers on "Butterworth filter published in 2006"
TL;DR: In this paper, a microstrip bandpass filter using stepped-impedance resonators is designed in low-temperature co-fired ceramic technology for dual-band applications at 2.4 and 5.2 GHz.
Abstract: A microstrip bandpass filter using stepped-impedance resonators is designed in low-temperature co-fired ceramic technology for dual-band applications at 2.4 and 5.2 GHz. New coupling schemes are proposed to replace the normal counterparts. It is found that the new coupling scheme for the interstages can enhance the layout compactness of the bandpass filter; while the new coupling scheme at the input and output can improve the performance of the bandpass filter. To validate the design and analysis, a prototype of the bandpass filter was fabricated and measured. It is shown that the measured and simulated performances are in good agreement. The prototype of the bandpass filter achieved insertion loss of 1.25 and 1.87 dB, S11 of -29 and -40 dB, and bandwidth of 21% and 12.7% at 2.4 and 5.2 GHz, respectively. The bandpass filter is further studied for a single-package solution of dual-band radio transceivers. The bandpass filter is, therefore, integrated into a ceramic ball grid array package. The integration is analyzed with an emphasis on the connection of the bandpass filter to the antenna and to the transceiver die
228 citations
TL;DR: In this article, a dual-mode dual-band bandpass filter using stacked-loop structure is proposed, which allows two transmission paths to radio frequency (RF) signals, each of them using dualmode resonators results in respective passband.
Abstract: In this letter, a dual-mode dual-band bandpass filter using stacked-loop structure is proposed, which allows two transmission paths to radio frequency (RF) signals. Each of them using dual-mode resonators results in respective passband. This can provide convenience to easily change one passband frequency, while another keeps almost the same. Several attenuation poles in the stopband are realized to improve the selectivity of the proposed bandpass filter. The theoretical and measured results are presented and show good agreement
174 citations
TL;DR: A low-power, highly linear, integrated, active-RC filter exhibiting a reconfigurable transfer function (Chebyshev, Elliptic) and bandwidth and a digital automatic tuning scheme to account for process and temperature variations is presented.
Abstract: In this paper, a low-power, highly linear, integrated, active-RC filter exhibiting a reconfigurable transfer function (Chebyshev, Elliptic) and bandwidth (5 MHz, 10 MHz), is presented. The filter exploits digitally-controlled polysilicon resistor banks and a digital automatic tuning scheme to account for process and temperature variations. The operational amplifiers used are based on a new compensation technique that allows optimized high-frequency filter performance and minimized current consumption. A filter prototype has been fabricated in a 0.12-mum CMOS process, occupies 0.25 mm2 (tuning circuit included), and achieves an IIP3 of approximately +20 dBm, whereas its spurious free dynamic range (SFDR) reaches 73 dB. The dissipation of the filter core and the tuning circuit is 4.6 mW and 1.5 mW, respectively
126 citations
TL;DR: In this article, a cross-shape defected ground structure (CSDGS) was proposed for low-pass filter with an ultra-wide stopband, which not only supports conventional DGS performances with a sharp rejection, but also exhibits an ultra wide stopband.
Abstract: This letter presents a novel low-pass filter with an ultra-wide stopband. The proposed filter is comprised of a new cross-shape defected ground structure (CSDGS). By using this structure, the filter not only supports conventional DGS performances with a sharp rejection, but also exhibits an ultra-wide stopband. For the deigned low-pass filter, an insertion loss of less than 2dB from dc to 3.5GHz and the rejection is better than 20dB from 4.3 to 15.8GHz. Predicted performances show widened and deepened stopband beyond the low passband. Furthermore, it is confirmed by measurement.
110 citations
TL;DR: In this article, a switchable bandpass filter with a wide stopband rejection was proposed, where the loaded diodes were used to switch the resonance conditions of the stepped-impedance resonators.
Abstract: Stepped-impedance resonators with diodes loaded at one end are used to develop switchable bandpass filters in this paper. The loaded diodes are used to switch the resonance conditions of the stepped-impedance resonators. The equations for resonance conditions of the stepped-impedance resonators with different loads at one end are derived and discussed. With these derived equations, the switchable filters can be easily designed and synthesized using the coupled-resonator filter theory. When the switchable filter is switched on, a bandpass filter response with a wide stopband rejection is achieved by making the on-state coupled resonators have the same fundamental resonant frequency, but different higher order resonant frequencies. When switched off, a high and wideband isolation is obtained by properly misaligning the resonant modes of the off-state resonators. The design concept is demonstrated by two single-pole-single-throw fourth-order Butterworth-type switchable microstrip bandpass filters, which utilize two and three switched stepped-impedance resonators, respectively. Finally, a compact single-pole-double-throw switchable microstrip bandpass filter using common resonators is demonstrated for wireless communication applications
86 citations
TL;DR: In this paper, the fundamental characteristics of a novel third-order RF balanced-to-unbalanced filter, namely, a balun filter, for integrated RF module applications are presented.
Abstract: In this paper, the fundamental characteristics of a novel third-order RF balanced-to-unbalanced filter, namely, a balun filter, for integrated RF module applications are presented. This center-tapped transformer-based new device works concurrently as a balun, an extracted-pole bandpass filter, and a matching network. As coupled resonant tanks are employed to perform the balun type of operation, traditional coupled-resonator filter theory can thus be used to design and analyze such a new device. Moreover, an extracted-pole technique is used not only for creating a transmission zero, but also provides a capability to match the filter with a complex load. In addition to providing a simple design procedure for the device, its working mechanism is also revealed mathematically. Specifically, return-loss sensitivity with respect to each resonator admittance and complex load matching capability are discussed in details. This balun filter has been implemented in a multilayered low-temperature co-fired ceramic substrate, demonstrating its promising potentials in miniaturized RF front-end modules. Experimental measurements are also presented to validate the theory and computer simulations.
85 citations
TL;DR: To prove the practical viability of the ultra-wideband filter topology based on high- and low-pass sections, a prototype at 4 GHz is designed, constructed in hybrid technology, and characterized.
Abstract: A systematic consistent and analytical method for the exact synthesis of ultra-wideband bandpass filtering responses using the isolated cascade connection of high- and low-pass sections is presented in this paper. Through the described synthesis technique, the optimum values for the design parameters of the high- and low-pass sections are computed from the initial specifications of the intended bandpass filtering profile. The theoretical results are validated with a synthesis example for both the Butterworth and Chebyshev cases. Furthermore, to prove the practical viability of the ultra-wideband filter topology based on high- and low-pass sections, a prototype at 4 GHz is designed, constructed in hybrid technology, and characterized. The main advantages of this wideband microwave bandpass filter solution are also highlighted
80 citations
TL;DR: The performance of the proposed CIC roll-off compensation filter is confirmed through computer simulation in such a way that bit error rate (BER) is minimized by compensating the roll- off characteristics.
76 citations
TL;DR: In this article, new floating immittance function simulators employing second-generation current controlled conveyors are proposed, employing only a single grounded capacitor as passive component and can realize either a negative or a positive floating inductor or capacitor.
Abstract: In this paper, new floating immittance function simulators employing second-generation current controlled conveyors are proposed. The first four of the presented circuits employ only a single grounded capacitor as passive component and can realize either a negative or a positive floating inductor or capacitor. The last two of the proposed circuits do not employ passive components and can realize either negative or positive floating resistances. All of the proposed circuits do not require passive element matching. As an application, a third-order butterworth filter is realized using the proposed positive floating inductance simulator. SPICE simulation results and large signal behavior of the filter are included.
66 citations
TL;DR: A tunable Q-enhanced filter with low passband distortion is presented and the Q of the on-chip spiral inductors that form the filter resonators is enhanced by using a cross-coupled differential pair which is degenerated by a second LC tank.
Abstract: A tunable Q-enhanced filter with low passband distortion is presented. The Q of the on-chip spiral inductors that form the filter resonators is enhanced by using a cross-coupled differential pair which is degenerated by a second LC tank. This technique allows for frequency dependent compensation of inductor losses and ensures that the Q-enhanced LC resonators have a frequency behaviour close to the ideal in the passband of the filter. The circuit allows DC voltage control of Q-enhancement. The filter centered at 2.0 GHz with a 130 MHz bandwidth is tunable in frequency by 3%, exhibits a -6.6 dBm 1-dB compression point and a 15 dB noise figure while consuming 17 mW of DC power. The circuit was fabricated in 0.18-mum CMOS and the performance was verified experimentally
64 citations
TL;DR: In this article, a coplanar-waveguide (CPW) bandpass filter using a dual-mode resonator is presented, where a square ring is used as the resonator, and a microstrip line stub attached the inner corner of the square-ring is used to perturbation element.
Abstract: A novel coplanar-waveguide (CPW) bandpass filter using a dual-mode resonator is presented in this letter. In the filter, a square-ring is used as the resonator, and a microstrip line stub attached the inner corner of the square-ring is used as the perturbation element. The square-ring and the input/output CPW are constructed on the two sides of a dielectric substrate, respectively. The filter has been investigated numerically and experimentally. Measured result shows that the filter has a minimum insertion loss of 1.2dB in its passband and an out-of-band rejection level of -45dB
TL;DR: In this paper, a back-to-back microstrip-CPW transition structure is proposed for ultra-wideband bandpass filter with an out-of-band rejection level of below -20.0 dB.
Abstract: A novel ultra-wideband bandpass filter based on a back-to-back microstrip-CPW transition structure is presented. The filter is composed of two microstrip-CPW transitions and a section of microstrip line used as a multiple-mode resonator. The filter has been investigated numerically and experimentally. Both simulated and measured results show that the filter has a good performance, including a small insertion loss, a group delay variation of less than 0.2 ns, stopband of up to 16.0 GHz at high frequencies, and an out-of-band rejection level of below -20.0 dB.
TL;DR: In this article, a highly selective dual-band stepped impedance bandpass filter is presented, where two finite out-of-band transmission zeros are realized, which have high selectivity.
Abstract: A highly selective dual-band stepped impedance bandpass filter is presented. The filter has two tunable passbands. Two finite out-of-band transmission zeros are realised, which have high selectivity.
TL;DR: In this paper, a quasielliptic microstrip bandpass filter (BPF) using both half-and quarter-wavelength resonators is proposed, which provides a 22.5dB rejection level from 1.14 f0 to 5.2 f0.
Abstract: A novel quasielliptic microstrip bandpass filter (BPF) using both half- and quarter-wavelength resonators is proposed. With the quarter-wavelength (lambda/4) resonators placed in the interstage, the filter spurious passband can be pushed up to 3 f0 where f0 stands for the passband center frequency. To improve the stopband characteristics, a modified stopband-extended filter is implemented, utilizing the multiple transmission zeros placed at specified frequencies to achieve good frequency selectivity and out-of-band rejection. The modified filter provides a 22.5-dB rejection level from 1.14 f0 to 5.2 f0
TL;DR: In this article, a dual-band lumped-element bandpass filter (DBLEF) is presented, which is implemented in low-temperature co-fired ceramic. But this filter is unique in that it utilizes only a single set of lumped components to create a dualpassband response.
Abstract: In this study, a dual-band lumped-element bandpass filter (DBLEF) is presented, which is implemented in low-temperature co-fired ceramic. The design utilizes the tight component coupling possible in this technology to mimic a much more complex network of lumped components. The filter is unique in that it utilizes only a single set of lumped components to create a dual-passband response. Detailed design equations are presented for the dual-band design, and a DBLEF having passbands at 2.4 and 5.2 GHz is demonstrated, representing the common wireless local area network bands. This paper both introduces a novel approach to lumped-element dual-band filtering, while also demonstrating an effective method of implementing this complex filter in multilayer technology with a very small footprint. Both measured and simulated results verify the approach with the overall size of the filter only 154times135times22.8 mil3 (3.85times3.38times0.57 mm 3)
TL;DR: In this article, a narrowband high-temperature superconducting (HTS) bandpass filter with a fractional bandwidth of 0.35% in the L band was proposed.
Abstract: This paper reports a recent development of a narrowband high-temperature superconducting (HTS) bandpass filter with a fractional bandwidth of 0.35% in the L band. The filter exhibits a 10-pole quasi-elliptic function response implemented with a cascaded quadruplet coupling structure. The measured filter shows a midband insertion loss of 0.26 dB and a return loss better than −15 dB over the passband. Steep rejection slopes are obtained at the band edges and the measured skirt slope has exceeded 120 dB MHz−1, resulting in an excellent out-of-band rejection very close to the band-edge. Combining this filter together with a special designed low-noise amplifier (LNA) as well as a cryo-cooler, an HTS subsystem was then constructed and mounted in the front end of a wind-profiler radar system, substituting the corresponding conventional parts. A field trial has shown that the HTS filter could markedly improve the sensitivity as well as the anti-interference capability of a wind-profiler radar system.
TL;DR: In this article, a universal current-mode active-C filter simultaneously realizes low-pass, band-pass and high-pass responses is proposed, which can also realize notch and all pass responses with interconnection of relevant output currents.
Abstract: A universal current-mode active-C filter simultaneously realizing low-pass, band-pass and high-pass responses is proposed The filter can also realize notch and all-pass responses with interconnection of relevant output currents The presented filter employs four second-generation current controlled conveyors (CCCIIs) as active elements and only two capacitors as passive elements The proposed active-C filter can be tuned electronically, and has low element sensitivities
TL;DR: A new algorithm has been developed to minimize the objective function by optimizing the filter tap weights by using Marquardt optimization method, which is better than that of the already existing methods.
TL;DR: In this article, a high-temperature superconducting bandpass filter at 408 MHz using microstrip quarter-wavelength spiral resonators is demonstrated, which achieves a symmetrical quasi-elliptic characteristic by using two cross-coupling links.
Abstract: A high-temperature superconducting bandpass filter at 408 MHz using microstrip quarter-wavelength spiral resonators is demonstrated. The quarter-wavelength spiral resonators were shorted to ground, as in a combline filter, via a grounding strip that is attached to the box wall by a number of aluminum bonding wires. The introduction of the normal metal wires does not introduce a measurable attenuation. The filter achieves a symmetrical quasi-elliptic characteristic by using two cross-coupling links. The experimental results of the filter are in very good agreement with the simulated ones.
01 Dec 2006
TL;DR: In this paper, a dual-band bandstop filter (DBBSF) is proposed by using composite shunt resonators, and an approximate design method is developed based on the lumped-element circuit of the filter.
Abstract: In this paper, a novel dual-band bandstop filter (DBBSF) is proposed by using composite shunt resonators, and an approximate design method is developed based on the lumped-element circuit of the filter. Both the midband frequencies and the stopband widths of the dual bands of the filter can be controlled separately. A dual-band BSF with center frequencies of 1.7 and 2.3 GHz is designed and fabricated using microstrip lines. The measured frequency response agrees excellently with theoretical predictions, validating well the proposed design theory and filter structure.
01 Sep 2006
TL;DR: In this paper, a compact ultra wideband (UWB) bandpass filter with a fractional bandwidth (FBW) of about 110% and transmission zero at the high frequency edge is presented using a microstrip structure.
Abstract: A compact ultra-wideband (UWB) bandpass filter with a fractional bandwidth (FBW) of about 110% and transmission zero at the high frequency edge is presented using a microstrip structure. The filter is based on a circuit model for an optimum stub filter consisting of only 5 short-circuited stubs separated by non-redundant connecting lines. As a result, the filter in a compact structure exhibited a selective filtering characteristic equivalent to a 9-pole Chebyshev filter. The design was successfully realized in theory and verified by full-wave EM simulation of the full layout and the experiment. The proposed filter had low insertion loss, sharp rejection, and excellent performance both inside and outside the band.
05 Jul 2006
TL;DR: A new method that performs zero phase filtering to extract a periodic signal within a predetermined frequency band is presented and is implemented in an experiment to perform active stabilization of video images captured by a camcorder subjected to an oscillatory disturbance with varying frequency.
Abstract: Periodic physiological motions have been a source of disturbance to many medical interventions and diagnostics that require high precision. This paper presents a new method that performs zero phase filtering to extract a periodic signal within a predetermined frequency band. The basic concept of the proposed adaptive zero phase bandpass filter is to design a pair of cascaded lowpass and highpass IIR filters, such that the phase lag caused by the lowpass filter is balanced by the phase lead introduced by the highpass filter. Since phase angle of a IIR filter is frequency dependent, we adopt the weighted-frequency Fourier linear combiner (WFLC) algorithm as an adaptive frequency estimator to provide the instantaneous dominant frequency of the signal of interest to the system to adjust the filter coefficients to yield the required performance. The proposed filter is implemented in an experiment to perform active stabilization of video images captured by a camcorder subjected to an oscillatory disturbance with varying frequency
TL;DR: A sixth-order 10.7-MHz bandpass switched-capacitor filter based on a double terminated ladder filter that presents both better accuracy and higher slew rate than previously reported Class-A OTA topologies is presented.
Abstract: A sixth-order 10.7-MHz bandpass switched-capacitor filter based on a double terminated ladder filter is presented. The filter uses a multipath operational transconductance amplifier (OTA) that presents both better accuracy and higher slew rate than previously reported Class-A OTA topologies. Design techniques based on charge cancellation and slower clocks are used to reduce the overall capacitance from 782 down to 219 unity capacitors. The filter's center frequency and bandwidth are 10.7 MHz and 400 kHz, respectively, and a passband ripple of 1 dB in the entire passband. The quality factor of the resonators used as filter terminations is around 32. The measured (filter + buffer) third-intermodulation (IM3) distortion is less than -40 dB for a two-tone input signal of +3-dBm power level each. The signal-to-noise ratio is roughly 58 dB while the IM3 is -45 dB; the power consumption for the standalone filter is 42 mW. The chip was fabricated in a 0.35-mum CMOS process; filter's area is 0.84 mm2
TL;DR: The tunable dispersion filter is a new design approach presented in this letter to provide dispersion modeling for digital waveguide synthesis of musical instruments, which do not produce extremely inharmonic sounds, such as the piano.
Abstract: The tunable dispersion filter is a new design approach presented in this letter to provide dispersion modeling for digital waveguide synthesis of musical instruments, which do not produce extremely inharmonic sounds, such as the piano. We propose to use a cascade of second-order allpass filters for modeling dispersion. The filter coefficients can be calculated by using simple formulae based on the Thiran allpass filter design, which is usually used for fractional delay approximation. Unlike the previous allpass filter approximations, this filter design is easily scalable to produce various inharmonicity values for a wide range of fundamental frequencies.
11 Jun 2006
TL;DR: A reconfigurable filter is realized using electromagnetic bandgap structures (EBG) which can be switched from bandpass to bandstop filter at the same frequency by PIN diodes and the dispersion diagram is obtained.
Abstract: In this paper, a reconfigurable filter is realized using electromagnetic bandgap structures (EBG) which can be switched from bandpass to bandstop filter at the same frequency by PIN diodes. A unit model for the reconfigurable filter is derived by equivalent circuit approach and full wave electromagnetic simulation is used for extracting the values of the lumped elements. The extracted parameters show that the bandpass and bandgap effect of the EBG cells. The dispersion diagram is obtained for the structure by combining the commercial software and the Floquet's theorem. The PIN diodes are used to switch from bandpass to bandstop filter. The measurement results show that the insertion loss in bandpass filter is around 2.1 dB and the 3-dB bandwidth is around 5.2 GHz which is suitable for wideband applications. For the bandstop filter, the 20 dB rejection bandwidth is 5.3 GHz and the insertion loss in the pass band is 1.6 dB.
Patent•
23 May 2006TL;DR: In this article, the authors presented a ladder-based acoustic wave filter with an inductor between a ground and at least one of the parallel-arm resonators in the ladder filter and a resonance circuit that is provided in parallel with the inductor.
Abstract: An acoustic wave filter includes: a ladder filter that has acoustic wave resonators connected in series and parallel arms; an inductor that is provided between a ground and at least one of the parallel-arm resonators in the ladder filter; and a resonance circuit that is provided in parallel with the inductor, and is located between the ground and the parallel-arm resonators in the ladder filter. In this acoustic wave filter, the resonance frequency of the resonance circuit is expressed as: 2f0−150 MHz
TL;DR: In this article, a dual-bandpass filter that utilizes a serial configuration of the inductive coupled-line (ICL) filter and the capacitive coupled line (CCL) filters is investigated.
Abstract: A dual-bandpass filter that utilizes a serial configuration of the inductive coupled-line (ICL) filter and the capacitive coupled-line (CCL) filter is investigated in this study. Numerical analysis is presented for the difference between the ICL and CCL filters. The dual-bandpass filter has a similar behavior to the individual single-band filter around the corresponding passband. An extra transmission zero can be generated between the two passbands of the dual-bandpass filter in that the ICL and CCL filters exhibit an out-of-phase response. Four architectures of dual-bandpass filters are proposed for the 2.4/5-GHz systems. Two of them are demonstrated by the low-temperature co-fired ceramic multilayer technology. Measurements results agree quite well with the simulation ones
TL;DR: The proposed method provides compact closed-form answers expressed explicitly in terms of the values of the circuit elements and is found to be in good agreement with Cadence simulations for the cases of a lossy integrator and a third-order Butterworth low-pass filter.
Abstract: State space harmonic distortion modeling and estimation are introduced for G/sub m/-C filters with fully balanced, weakly nonlinear tranconductors. The proposed method provides compact closed-form answers expressed explicitly in terms of the values of the circuit elements. It can be easily implemented in MATLAB and applied to G/sub m/-C filters of any order. The filter is viewed as a composition of three operators in signal space representing the input stage, the filter core, and the output stage. Each operator is then decomposed into the superposition of a linear operator and a nonlinear operator. The total distortion at the output is shown to be approximately the sum of the distortion introduced by the nonlinear operator of each stage. The theoretical results are found to be in good agreement with Cadence simulations for the cases of a lossy integrator and a third-order Butterworth low-pass filter.
TL;DR: In this article, the real cepstrum is used to design an arbitrary length minimum-phase finite-impulse response filter from a mixed-phase prototype, and only two fast Fourier transforms and a recursive procedure are required to find the filter's impulse response.
Abstract: The real cepstrum is used to design an arbitrary length minimum-phase finite-impulse response filter from a mixed-phase prototype. There is no need to start with the odd-length equiripple linear-phase filter first. Neither the phase-unwrapping nor root-finding procedure is needed. Only two fast Fourier transforms and a recursive procedure are required to find the filter's impulse response from its real cepstrum. The resulting filter's magnitude response is exactly the same as the original one even when the filter is of very high order
01 Nov 2006
TL;DR: In this paper, a computationally efficient 16-band non-uniformly spaced digital FIR filter bank is proposed for hearing aid applications, which is constructed by three prototype filters based on the principle of frequency-response masking technique.
Abstract: A computationally efficient 16-band non-uniformly spaced digital FIR filter bank is proposed for hearing aid applications. The filter bank is constructed by three prototype filters based on the principle of frequency-response masking technique. It requires only 34 multiplications in the implementation of a 16-band filter bank with stopband attenuation of -60dB. The simulation results show that the proposed filter bank achieves good matching between audiograms and filter magnitude responses. The filter delay is significantly reduced compared to that of the 8-band non-uniform filter bank [8].