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Showing papers on "Butterworth filter published in 2005"


Proceedings ArticleDOI
12 Jun 2005
TL;DR: In this paper, an ultra wideband (UWB) bandpass filter using broadside-coupled microstrip-coplanar waveguide structure has been proposed for UWB systems.
Abstract: This paper presented an ultra-wideband (UWB) bandpass filter using broadside-coupled microstrip-coplanar waveguide structure. The filter consists of a microstrip line coupled to a coplanar waveguide (CPW) that was fabricated on the ground of the microstrip line. The proposed filter has been simulated, fabricated and measured for UWB system. The measured results demonstrated the UWB properties from 3.0 GHz to 10.63 GHz (-10 dB bandwidth) and the potential to be wider. A threesection filter shown insertion loss at central frequency is about 0.32 dB and very flat over the whole band. The group delay, which is important to an impulse radio UWB system, is about 0.42 ns over the most central band and less than 0.95 ns over the whole band. The filter also exhibited a good performance outside the band, both at low frequency end (to meet FCC limit) and high frequency end higher than 18 GHz with insertion loss larger than 30 dB.

226 citations


Journal ArticleDOI
17 Jan 2005
TL;DR: In this article, a new combline filter structure with a continuous tunability for both the center frequency and bandwidth is presented, which is achieved by placing variable coupling reducers between the filter resonators.
Abstract: A new combline filter structure with a continuous tunability for both the center frequency and bandwidth is presented in this paper. The passband-width tunability is achieved by placing variable coupling reducers between the filter resonators. The coupling reducers, operating as bandwidth control subnetworks, are designed as detuned resonators made up of a line segment ending in a variable capacitor. The proposed filter structure is experimentally validated with the design, construction in suspended stripline technology, and characterization of a low-cost filter prototype for terrestrial digital video broadcasting receivers operating in the UHF band (470-862 MHz). Other relevant factors, such as the intermodulation distortion produced by the varactors used to control the bandwidth electronically or the power-handling performance of the constructed filter, are also discussed. The reconfigurable filter module described in this paper is very suitable for the design of flexible multifunction receiver subsystems simultaneously supporting signals with a different bandwidth.

225 citations


Journal ArticleDOI
TL;DR: In this paper, a fully-digital-controlled shunt hybrid active filter for damping of harmonic propagation in power distribution systems is presented, which is based on installation of a shunt pure active filter at the end of a feeder.
Abstract: This paper presents a fully-digital-controlled shunt hybrid filter for damping of harmonic propagation in power distribution systems. The harmonic propagation is caused by resonance between line inductances and power capacitors installed for power factor correction. A possible solution to damping out harmonic propagation is based on installation of a shunt pure active filter at the end of a feeder. This paper proposes a shunt hybrid active filter characterized by series connection of a seventh-tuned LC filter per phase and a small-rated three-phase active filter. Like the pure filter, the hybrid filter is connected to the end bus of a feeder. The capacitor of the LC filter imposes a high impedance to the fundamental frequency, so that the fundamental voltage appears across the capacitor. This unique feature allows us to directly connect the hybrid filter to the 6.6-kV power line without step-down transformers. Furthermore, the capacitor used in this hybrid filter is lighter, cheaper and smaller than the transformer used in the pure filter. Theoretical analysis, along with experimental results obtained from a 200-V, 20-kW laboratory system, verifies the viability and effectiveness of the proposed hybrid filter.

193 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: The work that led to what is now known as the Parks-McClellan algorithm is described, i.e., the Remez exchange algorithm with optimal Chebyshev approximation for FIR filter design.
Abstract: This article describes the work that led to what is now known as the Parks-McClellan algorithm. Within the bigger picture of filter design methods, this paper recount events that had an impact on the inspiration to develop the Parks-McClellan algorithm, i.e., the Remez exchange algorithm with optimal Chebyshev approximation for FIR filter design.

101 citations


Proceedings ArticleDOI
16 Jun 2005
TL;DR: In this article, the authors proposed a novel method for LCL type filter design, which makes the task very convenient and can be easily done by solving the equations by step-by-step design procedure, which is verified on the experimental set-up.
Abstract: LCL type filter becomes more and more attractive as utility interface for grid-connected voltage source rectifier (VSR). Compared to L type filter, LCL type filter can render better switching harmonics attenuation using lower inductance, which makes it suitable for higher power applications. However, LCL filter design is complex and needs to consider many constraints, such as current ripple through inductors, total impedance of the filter, switching harmonic attenuation, resonance phenomenon and reactive power absorbed by filter capacitors, etc. Try-error method is inconvenient and time-consuming. This paper proposes a novel method for LCL type filter design, which makes the task very convenient. At first, the total inductance should be determined according to current ripple requirement. With filter capacitor insertion, total inductance is split into two parts. A set of equations is obtained to represent the relationship between the impedances at switching frequency with consideration of switching harmonic attenuation and reactive power constrains. The other constraints are considered as the limitation for solvability condition for equations. So the overall design can be easily done by solving the equations. Step-by-step design procedure is described as a design example, which is verified on the experimental set-up

87 citations


Journal ArticleDOI
TL;DR: In this paper, a third-order G/sub m/-C Butterworth low-pass filter is proposed for zero-IF radio receiver architecture for multimode mobile communications, with a cutoff frequency range from 50 kHz to 2.2 MHz.
Abstract: A third-order G/sub m/-C Butterworth low-pass filter implementing G/sub m/-tuning and G/sub m/-switching to maximize the tuning range is described. This filter is intended to be used as a channel-selection/anti-aliasing filter in the analog baseband part of a zero-IF radio receiver architecture for multimode mobile communications. Its G/sub m/-switching feature allows extending the tuning range and adapting the power consumption. The filter's cutoff frequency ranges from 50 kHz to 2.2 MHz. An Input IP3 of up to +18 dBV/sub p/ is achieved, for a total worst-case power consumption of 7.3 mW for both I and Q paths, and an effective area of less than 0.5 mm/sup 2/ in a 0.25-/spl mu/m SiGe BiCMOS process. A new figure of merit is introduced for comparison of published low-pass tunable filters including noise, linearity, and tuning range.

87 citations


Journal ArticleDOI
TL;DR: In this article, a miniaturized dual-mode microstrip bandpass filter with the right crossed slots was proposed, which shows a 4.4% fractional bandwidth at 1.595GHz with a return loss of better than 10dB and an insertion loss of less than 2.5dB.
Abstract: This letter presents a miniaturized dual-mode microstrip bandpass filter with the right crossed slots. The right crossed slots perturb and reduce the fundamental resonant frequency, but the second resonance is not affected. Therefore, the second resonance will be effectively higher than 2f/sub o/, where f/sub o/ is the fundamental frequency. Since the fundamental frequency is lower, the bandpass filter is smaller than the conventional filter. The proposed filter shows a 4.4% fractional bandwidth at 1.595GHz with a return loss of better than 10dB and an insertion loss of less than 2.5dB, while the second passband is located around 2.88f/sub o/= 4.6GHz. Compared with the conventional square patch filter, the proposed filter also shows a 58% size reduction.

82 citations


Journal ArticleDOI
TL;DR: In this paper, an effective and easy-to-implement frequency filter is proposed, obtained by convolving a raised-cosine window with the ideal rectangular filter response function.
Abstract: An effective and easy-to-implement frequency filter is proposed, obtained by convolving a raised-cosine window with the ideal rectangular filter response function. Three other filters, Hodrick--Prescott, Baxter--King, and Christiano--Fitzgerald, are thoroughly reviewed. A bandpass version of the Hodrick--Prescott filter is also introduced and used. The behavior of the windowed filter is compared to the others through their frequency responses and by applying them to both quarterly and monthly artificial, known-structure series and real macroeconomic data. The windowed filter has almost no leakage and is better than the others at eliminating high-frequency components. Its response in the passband is significantly flatter, and its behavior at low frequencies ensures a better removal of undesired long-term components. These improvements are particularly evident when working with short-length time series, which are common in macroeconomics. The proposed filter is stationary and symmetric, therefore, it induces no phase-shift. It uses all the information contained in the input data and stationarizes series integrated up to order two. It thus proves to be a good candidate for extracting frequency-defined series components.

80 citations


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%.

73 citations


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: In this paper, a miniaturized dual-mode ring bandpass filter at 1.45 GHz with a bandwidth of 6% was demonstrated, which was achieved by loading the peripheral of the ring with the butterfly radial stub structure.
Abstract: A miniaturized dual-mode ring bandpass filter at 1.45 GHz with a bandwidth of 6% is demonstrated. The perturbation of the dual modes is realized by a pair of local ground defects. The miniaturization is achieved by loading the peripheral of the ring with the butterfly radial stub structure. A 41% loading factor has been achieved using this method. The simulated and measured results are in good agreement.

Proceedings Article
01 Jan 2005
TL;DR: A new figure of merit is introduced for comparison of published low-pass tunable filters including noise, linearity, and tuning range, as well as intended as a channel-selection/anti-aliasing filter in the analog baseband part of a zero-IF radio receiver architecture for multimode mobile communications.
Abstract: A third-order G m -C Butterworth low-pass filter implementing G m -tuning and G m -switching to maximize the tuning range is described. This filter is intended to be used as a channel-selection/anti-aliasing filter in the analog baseband part of a zero-IF radio receiver architecture for multimode mobile communications. Its G m -switching feature allows extending the tuning range and adapting the power consumption. The filter's cutoff frequency ranges from 50 kHz to 2.2 MHz. An Input IP3 of up to +18 dBVp is achieved, for a total worst-case power consumption of 7.3 mW for both I and Q paths, and an effective area of less than 0.5 mm 2 in a 0.25-μm SiGe BiCMOS process. A new figure of merit is introduced for comparison of published low-pass tunable filters including noise, linearity, and tuning range.

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.

Journal ArticleDOI
TL;DR: In this paper, a dual-band bandpass filter topology was proposed and fabricated with low temperature co-fired ceramic (LTCC) technology for miniaturized implementation.
Abstract: This letter proposes and fabricates a novel dual-band bandpass filter topology. The proposed topology facilitates the split resonating frequencies of coupled resonator pairs in realizing the dual-band response and introduces transmission zeros for improving the stopband attenuation. The semi-lumped prototype enables the integration of the filter in a multilayer circuit for miniaturized implementation. Finally, a design example fabricated with low temperature co-fired ceramic (LTCC) technology is presented for validating the filter configuration.

Patent
16 Mar 2005
TL;DR: A high-frequency circuit for branching highfrequency signals for pluralities of communications systems of different frequencies is defined in this article, which comprises a lowpass filter circuit disposed between first and second ports and/or a high-pass filter circuits disposed between the first port and a fourth port.
Abstract: A high-frequency circuit for branching high-frequency signals for pluralities of communications systems of different frequencies, which comprises a lowpass filter circuit disposed between first and second ports and/or a highpass filter circuit disposed between the first port and a fourth port; and a matching circuit and a bandpass filter circuit disposed between the first port and a third port; the lowpass filter circuit, the highpass filter circuit and the matching circuit comprising capacitance elements and inductance elements; the bandpass filter circuit being a SAW filter; and the passband f 1 of the lowpass filter circuit, the passband f 2 of the bandpass filter circuit, and the passband f 3 of the highpass filter circuit meeting the condition of f 1

Journal ArticleDOI
TL;DR: This letter, when considering a prototype version of a Fourier-based median filter, defines the set of user-defined options that are available and also defines a possible solution to solve the distortions caused around the dc component due to natural spectrum decay.
Abstract: An efficient technique to remove periodic noise from digital images via a novel implementation of the median filter is presented and discussed within this letter. The technique is based on applying the nonlinear filter to the Fourier amplitude spectrum of the image. Since the median filter is normally used to spatially reduce spiky noise in digital images, using this filter in Fourier space is especially useful for removing periodic frequency noise. Provisional experimental results are shown that demonstrate that the proposed filter provides good performance when compared with a similar Fourier filter: the notch filter. This letter, when considering a prototype version of a Fourier-based median filter, defines the set of user-defined options that are available and also defines a possible solution to solve the distortions caused around the dc component due to natural spectrum decay.

Patent
16 Mar 2005
TL;DR: In this paper, the authors propose a high-frequency circuit for demultiplexing highfrequency signals of communication methods of different frequencies, which consists of a low-pass filter circuit between first and second ports and/or a high pass filter circuit provided between the first port and a forth port.
Abstract: A high-frequency circuit for demultiplexing high-frequency signals of communication methods of different frequencies. The high-frequency circuit comprises a lowpass filter circuit provided between first and second ports and/or a highpass filter circuit provided between the first port and a forth port and a matching circuit and a bandpass filter both provided between the first port and a third port. The lowpass filter circuit, the highpass filter circuit, and the matching circuit each have a capacitance element and inductance element. The bandpass filter circuit is composed of an SAW filter. The passband f1 of the lowpass filter circuit, the passband f2 of the bandpass filter circuit, and the passband f3 of the highpass filter are in a relation f1

Journal ArticleDOI
TL;DR: A low-voltage low-power signal processing chip for electrocardiogram measurements has been designed and manufactured and is very suitable for portable applications such as heart rate detectors.
Abstract: A low-voltage low-power signal processing chip for electrocardiogram measurements has been designed and manufactured. The circuit includes a continuous time, offset-compensated preamplifier with an amplification of 40 dB, an eighth-order Butterworth switched-opamp switched-capacitor (SO-SC) filter with a passband of 8-30 Hz, a 32-kHz crystal oscillator, an SO-SC postamplifier, and a bias circuit. The whole circuit operates with supply voltages from 1.0 to 1.8 V and the measured average current consumption is only about 3 /spl mu/A. The circuit is therefore very suitable for portable applications such as heart rate detectors.

Proceedings ArticleDOI
01 Jan 2005
TL;DR: In this paper, a 3GHz-10GHz ultra wideband (UWB) low noise amplifier (LNA) typology was proposed, which achieved 14.5~15.3dB gain from 3GHz to 10GHz and 3.43dBm IIP3 in 5GHz, and dissipated 4.3mW without the output buffer.
Abstract: In this paper, a 3GHz-10GHz ultra wideband (UWB) low noise amplifier (LNA) typology is proposed. The broadband matching and the flat gain are two important factors for the broadband circuits. Besides those factors, the minimal noise figure (NF), good linearity, and the lower power consumption are also desired. The common gate input stage with the 3rd order Butterworth filter configuration is used in the proposed LNA to achieve the broadband input matching. The flat gain of the LNA is achieved by the combination of the inductor peaking load and the shunt inductor insertion between the cascade stages of LNA. The LNA is designed in the standard 0.18mum CMOS technology. It achieved 14.5~15.3dB gain from 3GHz to 10GHz and 3.43dBm IIP3 in 5GHz, operates from 1.8V power supply, and dissipates 4.3mW without the output buffer

Proceedings ArticleDOI
31 Oct 2005
TL;DR: A flexible synthesis procedure for generating current-mode active filters using current differencing transconductance amplifiers is given and a new nth-order low-pass filter is proposed.
Abstract: A flexible synthesis procedure for generating current-mode active filters using current differencing transconductance amplifiers is given. The proposed method is based on drawing the signal-flow graph from the given transfer function and obtaining the circuit realization from the graph. By using this method, a new nth-order low-pass filter is proposed. The simulation results for the sixth order Butterworth filter are also included.

Journal ArticleDOI
TL;DR: In this paper, a four-pole quasi-elliptic function bandpass filter for a compact low-temperature co-fired ceramic is proposed, which is constructed by the open-loop resonators and the miniaturized hairpin resonators that can be coupled through the apertures on the common ground plane.
Abstract: A four-pole quasi-elliptic function bandpass filter for a compact low-temperature cofired ceramic is proposed in this paper. The filter is constructed by the open-loop resonators and the miniaturized hairpin resonators that can be coupled through the apertures on the common ground plane, and the 0/spl deg/ feed structure adds two extra transmission zeros to the filter response. It is shown that the filter occupies a very small size. As a result, the proposed structure of the filter occupies a very small circuit area and has a good out-of band rejection.

Patent
21 Apr 2005
TL;DR: In this paper, a digital filter is designed by combining unit filters having a predetermined asymmetric numerical sequence as filter coefficients (H 1 to H 3 ) which reduces the number of taps required for the digital filter designed, eliminates use of a window function, and prevents generation of a discretization error in the filter characteristic obtained
Abstract: A digital filter is designed by combining unit filters (L 10 ′, H 10 ′) having a predetermined asymmetric numerical sequence as filter coefficients (H 1 to H 3 ) Thus, it is possible to automatically obtain a desired digital filter coefficient only by combining the unit filter Moreover, a symmetric numerical sequence {−1, 0, 9, 16, 9, 0, −1}/32 is divided at the center into two parts and one of them is used as the asymmetric filter coefficients (H 1 to H 3 ) This reduces the number of taps required for the digital filter designed, eliminates use of a window function, and prevents generation of a discretization error in the filter characteristic obtained

Journal ArticleDOI
TL;DR: In this paper, a compact composite low-pass filter, designed by the image parameter method and semilumped component approach, is described and results for cutoff frequency ranging from C- to V-band.
Abstract: A compact composite low-pass filter, designed by the image parameter method and semilumped component approach, will be described and results for cutoff frequency ranging from C- to V-band will be presented. This composite design combines four filter sections and the presence of a strong attenuation pole near the cutoff frequency provides an extremely sharp attenuation response, while ensuring good matching properties in the passband, making this filter design very attractive for harmonic spurious response suppression or diplexing. The lumped-element schematic of the filter has been implemented using a combination of a stepped-impedance filter and folded stepped-impedance resonators. The overall folded layout has been optimized using full-wave simulation and occupies an ultra-compact area of only 5/spl times/5 mm/sup 2/ for a C-band filter. Measured results exhibit rejection of the attenuated pole greater than 40 dB. Similar filter designs have been realized for C- and V-bands. These filters have been fabricated on a liquid-crystal-polymer substrate demonstrating a high performance, ultra-compact, and very low-cost solution for RF and millimeter-wave applications.

Journal Article
TL;DR: In this article, a microstrip bandpass filter for ultra wideband (UWB) radio systems is proposed, based on a dual-modering resonator structure and with the addition of two stepped-impedance open.stubs.
Abstract: A novel, compact, microstrip bandpass filter for ultra-wideband (UWB) radio systems is proposed. This filter has a 3 dB fractional bandwidth of 60 percent, with low insertion loss and sharp rejection. Based on a dual-modering resonator structure and with the addition of two stepped-impedance open .stubs, it can provide a wide passband and two sharp stop-bands. A frequency rejection greater than -15 dB can be observed between 8 and 14 GHz with the proper position of tapped, lines at the input and output. The filter is designed for full duplex systems in satellite communications.

Proceedings ArticleDOI
12 Jun 2005
TL;DR: In this paper, a lumped-element dual-band bandpass filter for low temperature co-fired ceramic (LTCC) implementation is proposed, which operates at 2.4 and 5.2 GHz.
Abstract: A lumped-element dual-band bandpass filter for low temperature co-fired ceramic (LTCC) implementation is proposed. Design equation formulations are presented. For demonstration, one RF filter operating at 2.4 and 5.2 GHz is designed. Simulated and measured results are provided.

Journal ArticleDOI
TL;DR: In this article, a new class of filter transfer functions, called chained-function filters, is described in theoretical detail, which can give a variety of transfer functions having the same order, but different frequency domain, time domain, and implementation characteristics.
Abstract: For the first time, the new class of filter transfer functions, called chained-function filters, is described in theoretical detail. The chained-function concept can give a variety of transfer functions, having the same order, but different frequency domain, time domain, and implementation characteristics. As a result, a filter can be selected to have the required reduction in sensitivity to manufacturing errors, resonator unloaded-Q, and filter losses. This can be achieved while maintaining a given return-loss level and a predetermined out-of-band rejection performance that is comparable with conventional Chebyshev filters. The transfer-function formulations are given in detail, as well as the analysis of frequency- and time-domain responses, resonator unloaded-Q requirements, and filter loss responses. Theoretical comparison with conventional Chebyshev filter characteristics confirm the already demonstrated advantages of this new family of filter transfer functions.

Journal ArticleDOI
TL;DR: The photonic realization of the active, adaptive lattice filter is described and the algorithms which map between gains space and filter coefficients space are presented and studied.
Abstract: Optical lattice filter structures including gains are introduced and analyzed. The photonic realization of the active, adaptive lattice filter is described. The algorithms which map between gains space and filter coefficients space are presented and studied. The sensitivities of filter parameters with respect to gains are derived and calculated. An example which is relevant to adaptive signal processing is also provided.

Proceedings ArticleDOI
18 Sep 2005
TL;DR: The paper presents the design of a wide-band active-RC filter with a fast tuning circuit for wireless communication receiver applications and the successive approximation register (SAR) scheme is incorporated for a prompt on-chip tuning operation that should be needed for compensating RC variations.
Abstract: The paper presents the design of a wide-band active-RC filter with a fast tuning circuit for wireless communication receiver applications. The filter topology is the 5/sup th/-order Chebyshev-II lowpass filter type and the programmable bandwidth can be extended up to 10MHz while the stopband attenuation larger than 40dB is obtained. The successive approximation register (SAR) scheme is incorporated for a prompt on-chip tuning operation that should be needed for compensating RC variations. The filter is fabricated in a 0.18-/spl mu/m standard digital CMOS technology and dissipates 20.7mW for a supply voltage of 1.8V. The measured 3/sup rd/-order harmonic input intercept point (IIP3) is larger than 32dBm.

Proceedings ArticleDOI
12 Jun 2005
TL;DR: In this paper, a hybrid topology based on series and parallel resonators is proposed for a miniaturized and wide band bandpass filter, where series resonators are realized using open-ended coupled lines and a parallel resonator is implemented using an openended stub.
Abstract: This paper deals with miniaturized and wide band bandpass filter. This filter is based on an original topology based on series and parallel resonators. Series resonators are realized using open-ended coupled lines and parallel resonator is implemented using an open-ended stub. This hybrid topology based on two kinds of stub leads to a twice more compact 5th order design compared to the conventional 5th order approach. Moreover, the use of resonators presenting different periodic behaviors implies additional transmission zeros and so, enhances the rejection of the filter. Liquid crystal polymer (LCP) is chosen by considering its low cost, good and stable RF performance over the frequency of interest and its ability to act both as a substrate and a package to obtain wide band filter. So, the combined use of this technology and this topology leads to a filter that presents very good electrical performances in a reduced occupied area. A compact wideband filter (2.38-4.2 GHz) with insertion loss of 1.2 dB and rejection has been designed by using a full-wave analysis and measurements are presented.