Elliptic Low-pass Filter Research Articles

Based on Rotating Machinery Data Acquisition System Anti-Aliasing Filter Design and Application

In this work, on the basis of the analysis of the component of traditional data acquisition system, and in view of the design requirement of data acquisition system for the process of rotating machinery testing and fault diagnosis, adopt the integrated with AD module based on the 8th -order low pass elliptic switched-capacitor filter MAX297 for filtering, thereby proposes a portable data acquisition system. And it gives the design proposal of anti-aliasing filter according to the design requirement, and illustrates the principle of filtering and accomplished the corresponding hardware circuit. And this proposal of the filter can be used to other testing and fault diagnosis systems by adjusting the sampling frequency.

A Compact UWB Bandpass Filter With Embedded SIR as Band Notch Structure

In this letter, an ultrawideband (UWB) bandpass filter with a band notch is proposed. The UWB BPF (3.1-10.6 GHz) is realized by cascading a distributed high-pass filter and an elliptic low-pass filter with an embedded stepped impedance resonator (SIR) to achieve a band notch characteristic. The notch band is obtained at 5.22 GHz. It is shown that the notch frequency can be tuned by changing the impedance ratio of the embedded SIR. A fabricated prototype of the proposed UWB bandpass filter is developed. The inband and out-of-band performance obtained by measurement, EM simulation, and that with an equivalent circuit model are in good agreement.

A High-IIP3 Third-Order Elliptic Filter With Current-Efficient Feedforward-Compensated Opamps

A low-distortion active filter is realized using current-efficient feedforward-compensated operational amplifiers in the integrators and feedforward current injection in the summing amplifier. A third-order elliptic low-pass filter with two possible bandwidth settings of 17 and 8.5 MHz consumes 1.8 mW from a 1.8-V supply and occupies 0.17 mm2 in a 0.18- μm CMOS process. The measured maximum signal-to-noise and distortion ratios at the two bandwidth settings are 50.5 and 52.5 dB, respectively. The corresponding third-order intermodulation intercept points (IIP3) are +28.2 and +30.8 dBm. Automatic tuning is used at the startup to counter process variations and set the bandwidth accurately.

Design of a Quasi- elliptic Lowpass Filter using A New Defected Ground Structure and Capacitively Loaded Microstrip Line

The modern microwave and millimeter wave communication system demands good filtering characteristics with compact sizes. In this paper the attention has been given towards the design of a good elliptical lowpass filter with sharp transition between passband and stopband, negligible passband insertion loss and wide stop band. A new defected ground structure (DGS) consisting of two square slots connects with a rectangular slot by two thin transverse slots underneath a microstrip line is proposed. In the frequency characteristics of proposed unit pattern provides an attenuation zero close to an attenuation pole. As a result, better transition sharpness, lower passband insertion loss and broader stopband are observed compares to dumbbell DGS. An equivalent lumped L-C network is proposed to model the introduced DGS unit and corresponding L-C parameters are extracted. A 3rd order quasi-elliptic lowpass filter with 1.4 GHz cut- off frequency, 1.7 GHz attenuation pole frequency, negligible passband insertion loss, almost 100 dB/GHz sharpness factor and 1.56GHz passband bandwidth (at -15 dB) is designed by cascading three investigated DGS units of different dimensions under capacitively loaded microstrip line.

Modeling of compact microstrip resonator using neural network: Application to design of compact low-pass filter with sharp cut-off frequency

In this article, S-parameters of compact microstrip resonator cell are predicted using artificial neural network (ANN) to design class of elliptic function compact low-pass filter with sharp cut-off frequency. The ANN structure used in this work is multilayer perceptron (MLP) neural network. The data used for training the network is obtained using electromagnetic (EM) simulator. We compared measurement results and simulation results of filter by EM-simulator and ANN. The results show accurate attenuation at cut off frequency. In comparison with EM-simulator, simulation results by ANN have merits such as: mitigated consumption time, efficient performance and good accuracy. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1323–1328, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26008

Log-Domain Filter Design Based on Impedance Scaling of LC Ladder Structures

In this paper, a log-domain filter design based on an impedance scaling technique of passive LC ladder structures is considered. To this end a general circuit for the simulation of any kind of two-terminal component, both grounded and floating, is presented. Depending on the kind of filter, the proposed technique can produce implementation advantages by reducing the number of required components. The validity of the approach is demonstrated through the simulation of a fifth-order LC ladder elliptic low-pass filter.

Compact Elliptic-Function Coplanar Waveguide Low-Pass Filters Using Backside Metallic Patterns

In this letter, compact elliptic-function low-pass filters (LPF) implemented in coplanar waveguide technology by etching stepped impedance resonators (SIR) in the back substrate side, are presented. The required transmission zeros of the elliptic-function response are provided by the shunt connected SIRs. As an illustrative example, an order-3 prototype LPF with 1 GHz cutoff frequency is designed and fabricated. The measured stop-band rejection is better than 30 dB up to 6.4 GHz, and a narrow transition band is obtained. To demonstrate the possibilities of the approach to synthesize arbitrary elliptic-function responses and order, a fifth-order elliptic LPF with 1 GHz cut-off frequency is also designed and fabricated. Filter dimensions are as small as 6.6 mm × 9.2 mm, i.e, 0.034λ × 0.047A, for the third-order filter, and 12.1 mm × 13 mm (0.062λ × 0.067λ) for the fifth-order filter, λ being the guided wavelength at cutoff.

A reconfigurable analog baseband circuit for WLAN, WCDMA, and Bluetooth

A reconfigurable analog baseband circuit for WLAN, WCDMA, and Bluetooth in 0.35 μm CMOS is presented. The circuit consists of two variable gain amplifiers (VGA) in cascade and a Gm–C elliptic low-pass filter (LPF). The filter-order and the cut-off frequency of the LPF can be reconfigured to satisfy the requirements of various applications. In order to achieve the optimum power consumption, the bandwidth of the VGAs can also be dynamically reconfigured and some Gm cells can be cut off in the given application. Simulation results show that the analog baseband circuit consumes 16.8 mW for WLAN, 8.9 mW for WCDMA and only 6.5 mW for Bluetooth, all with a 3 V power supply. The analog baseband circuit could provide −10 to +40 dB variable gain, third-order low pass filtering with 1 MHz cut-off frequency for Bluetooth, fourth-order low pass filtering with 2.2 MHz cut-off frequency for WCDMA, and fifth-order low pass filtering with 11 MHz cut-off frequency for WLAN, respectively.

Elliptic-function lowpass filter with sharp cutoff frequency using slit-loaded tapered compact microstrip resonator cell

A novel slit-loaded tapered compact microstrip resonator cell to design a class of elliptic function compact lowpass filter with sharp skirt characteristics is proposed. Several cells are connected in series form to obtain an excellent lowpass filter. The bandwidth is enhanced and the size is reduced compared to conventional tapered resonators. The results of filter simulation with an EM-simulator and measurement show accurate attenuation at cutoff frequency. The proposed filters have compact and simple structures, small sizes, high selectivity, wide stopband, low insertion loss, etc; all these features are the requirements of wireless communication circuits. Measurement results show good agreement with the simulation.

Compact Elliptic function Lowpass Filter based on Defected Ground Structure

A compact microstrip lowpass filter (LPF) with prominent cutoff sharpness and wide stopband is presented. The microstrip LPF is composed of a broadened microstrip line on the top side of the microstrip structure, an H-shaped defected ground structure (DGS) and a modified dumbbell (DB) DGS in the ground plane. It has a simple design procedure and easily can be tuned. The designed filter is developed and experimental results show that it has a sharp cutoff frequency response.

Microstrip Low-Pass Elliptic Filter Design Based on Implicit Space Mapping Optimization

It is a time-consuming and often iterative procedure to determine design parameters based on fine, accurate but expensive, models. To decrease the number of fine model evaluations, space mapping techniques may be employed. In this approach, it is assumed both fine model and coarse, fast but inaccurate, one are available. First, the coarse model is optimized to obtain design parameters satisfying design objectives. Next, auxiliary parameters are calibrated to match coarse and fine models’ responses. Then, the improved coarse model is re-optimized to obtain new design parameters. The design procedure is stopped when a satisfactory solution is reached. In this paper, an implicit space mapping method is used to design a microstrip low-pass elliptic filter. Simulation results show that only two fine model evaluations are sufficient to get satisfactory results.

Elliptic-Function CPW Low-Pass Filters Implemented by Means of Open Complementary Split Ring Resonators (OCSRRs)

In this letter, an elliptic low-pass filter (LPF) implemented in coplanar waveguide (CPW) technology by etching open complementary split ring resonators (OCSRRs) in the central strip is presented for the first time. The OCSRRs behave as series connected parallel resonant tanks, whereas metallic patches etched in the back side of the substrate provide the required shunt capacitance to achieve the elliptic function response. An order-5 elliptic LPF has been designed and fabricated to illustrate the possibilities of this new approach. The measured frequency response is in good agreement with the ideal elliptic function up to twice the cutoff frequency ( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">fc</i> =1& GHz). Since OCSRRs are electrically small resonators, filter dimensions are also small (device length is 2.5 cm, namely 0.13 lambda , where lambda is the guided wavelength at <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">fc</i> ). This work is illustrative of the possibilities of OCSRRs for the design of compact planar filters and other microwave components.

Design of coplanar waveguide elliptic low pass filters

This article proposes three design topologies of coplanar waveguide elliptic low pass filters. The design procedure is simple and explained in detail for the first topology. Numerical results are p...

Design of coplanar waveguide elliptic low pass filters

This article proposes three design topologies of coplanar waveguide elliptic low pass filters. The design procedure is simple and explained in detail for the first topology. Numerical results are provided using the commercially available simulation softwares IE3D and HFSS to show the validity of the design with very good agreement. The proposed filters yield less than 0.1 dB attenuation in the passband (0–2 GHz), with a controllable slope of the transition between passband and stopband. The width of the rejection band is increased by simple filter cascading resulting in a passband to stopband ratio of up to 1:6. © 2009 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2009.

A new 5th-order differential type class-AB log-domain elliptic lowpass filter for video frequency applications

This paper proposes a new current-mode 5th-order differential type class-AB log-domain elliptic lowpass filter for video frequency applications. The design is based on the state-space synthesis method. The proposed filter has 5.75 MHz cut-off frequency with maximum 0.177 dB passband ripple and attenuation greater than 40 dB at 7.88 MHz. Only BJTs and grounded capacitors were used, and operated with single power supply of 2.5 V. Since the parameters of proposed filter are tunable, it is easy to control of cut-off frequency. This adjustment is accomplished by changing external currents. SPICE simulations are given to confirm the theoretical analysis. For this purpose, the filter is simulated by using both idealized BJT models and AT&T CBIC-U2 type transistors.

Multi-Standard Mobile Broadcast Receiver LNA With Integrated Selectivity and Novel Wideband Impedance Matching Technique

A CMOS LNA supporting multiple mobile video standards (MediaFLO, DVB-H, and ISDB-T) is implemented using a 0.18 mum CMOS process. The LNA uses a novel feedback configuration and implements an RF elliptic low-pass filter (LPF) response. Because of this elliptic LPF response, the receiver is able to operate concurrently with radio transmitter leakage from GSM, DCS, WLAN, and Bluetooth. The design decouples the feedback path from the main path to allow integration of the LPF as well as obtain wideband input matching. Measurement results show voltage gain of 25 dB, NF of 1.6 dB, and IIP3 of -2 dBm in MediaFLO mode. DVB-H mode demonstrates voltage gain of 25 dB, NF of 1.8 dB, and IIP3 of -1 dBm while achieving interference rejection greater than 70 dB.

A New Class of Continuous-Time Delay-Compensated Parameter-Varying Low-Pass Elliptic Filters With Improved Dynamic Behavior

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> In some applications, it is required to have continuous-time low-pass analog filtering systems which simultaneously possess a constant group delay in the passband and a narrow transition band. Usually, these systems are implemented by adding to the output of a filter with steep-amplitude selectivity (an elliptic filter, for instance) an all-pass filter which compensates the unfavorable run of the group delay response of the first filter. However, this compensation process will also increase the duration of the transient response of the resulting filtering system. This paper presents a new class of delay-compensated parameter-varying low-pass elliptic filters with a transient response of short duration. This improvement is achieved by means of a temporary change in the value of the filter parameters when a steplike transition with a minimum amplitude is detected in the input signal. As a consequence of the control strategy used to induce parameter variations in the proposed class of filters, its behavior is nonlinear in nature. Therefore, its stability properties (and particularly their bounded-input bounded-output stability) are also assessed. Simulations verifying the effectiveness of the new class of filters are presented and compared to the performance of delay-compensated and delay-uncompensated elliptic filters which were chosen as study cases. </para>

Design of compact, broad-stopband lowpass filter using modified stepped impedance hairpin resonators

A compact elliptic function lowpass filter using a stepped impedance hairpin resonator is proposed. The filter has the advantages of compact size, low insertion loss, easy fabrication, a wide stopband, and sharp cutoff frequency response. In order to cause a sharp cutoff frequency response and the wide stopband suppression, a coupled stepped impedance resonator is taken into consideration for the newly proposed lowpass filter. A demonstration filter has been designed, fabricated and tested, and the results agree well with the theory. The size of the filter is less than 0.037λg×0.093λg, where λg is the waveguide length at the cutoff frequency 1.5 GHz, and the 10 dB rejection stopband can be extended to more than 15 GHz. The filter is useful for many microwave system applications.

A configurable L/S‐band integrated elliptical lowpass filter utilizing MEMS technology

AbstractIn this article, the design, analysis, and implementation of a dual band 1 GHz/3 GHz elliptical filter utilizing a micro‐electro‐mechanical systems (MEMS) switch is introduced. The band selection is achieved via MEMS‐switch configurable capacitor structures. The RF MEMS switch uses thermal actuation and is separately fabricated and characterized; the switch achieves an insertion loss of 0.7 dB and an isolation of 45 dB. The elliptical filter is implemented using active frequency‐dependent negative resistor (FDNR) structures. The filter achieves 29 dB of rejection at a 500 MHz offset from the 944 MHz corner, and 26.2 dB of rejection at a 1 GHz offset from the 3.06 GHz corner. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2791–2794, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23828

다중 폴 저역 통과 여파기가 내장된 K-대역 LTCC 주파수 상향 변환기

본 논문에서는 위성 탑재 부품의 중요한 요구 특성 중의 하나인 부품의 소형화를 위해 LTCC를 이용하여 Ka-대역 OBS 위성 중계기용 주파수 상향 변환기를 개발하였다. 주파수 상향 변환기 내에 적층으로 S-대역 저역통과 여파기와 K-대역 대역 통과 여파기를 배치 하였으며, 주파수 상향 변환 MMIC 혼합기를 조립 하였다. S-대역 저역 통과 여파기 설계에서는 수정된 엘립틱(Elliptic) 저역 통과 여파기 구조를 이용하여 임의의 주파수에 폴을 형성함으로써 임의의 스퓨리어스 신호를 선택적으로 제거할 수 있는 방법을 제시하였다. K-대역 대역 통과 여파기의 경우, 층간 커플링을 이용한 구조를 채택하였다. 주파수 상향 변환 혼합기에는 MMIC 이중 평형 다이오드 혼합기를 사용하였다. 제작된 LTCC 주파수 상향 변환기의 삽입 손실은 9 dB, 격리도는 51 dBc이며, 크기는 <TEX>$8{\times}7{\times}0.6mm^3$</TEX>로 기 개발된 Ka-대역 OBS 위성 중계기용 주파수 상향 변환기에 비해 1/3 크기의 소형화를 이룰 수 있었다. This paper presents a low temperature co-fire ceramics(LTCC) Upconverter for a Ka-band OBS satellite transponder in order for size reduction which is one of the most important requirement for satellite components. A S-band low-pass filter(LPF), a K-band band-pass filter(BPF), and an upconverting MMIC mixer are embedded in the multi-layer structure of the upconverter. All spurious can be selectively rejected by employing a modified Elliptic low pass filter with a multi-pole structure for the S-band LPF. Also an improved performance of out-of-band rejection can be obtained. At the K-band BPF design a layer coupled configuration is employed. The upconverting mixer is an MMIC diode mixer with a double-balanced configuration. Conversion loss and isolation of the upconverter are 9 dB and 51 dBc, respectively. The size of the LTCC upconverter is only <TEX>$8{\times}7{\times}0.6mm^3$</TEX> which is one-third for the thin-film based upconverter.