Narrowband Bandpass Filter Research Articles

MULTISTAGE FILTERS FOR IDENTIFICATION OF EUKARYOTIC PROTEIN CODING REGIONS

A class of multistage filters, namely, real narrowband bandpass filter (RNBPF) has been previously used for identification of protein coding regions. This filter passes the frequency component at 2π/3 along with its conjugate. This conjugate frequency component may degrade the identification accuracy. To improve the identification accuracy, two types of multistage filters are proposed in this paper. A complex narrowband bandpass filter (CNBPF) is proposed for suppressing the conjugate frequency component which, in turn, reduces the background noise present in the deoxyribonucleic acid (DNA) spectrum and improves identification accuracy. By cascading RNBPF with moving average filter (RNBPFMA), another type of multistage filter is proposed. As moving average filter smooth out the rapid variations in the DNA spectrum, RNBPFMA improves the identification accuracy. The computational complexity of RNBPFMA is less than that of CNBPF. The RNBPF and proposed multistage filters are compared with previously reported short-time discrete Fourier transform (ST-DFT) method in terms of computational complexity. It is found that multistage filters reduce the computational load to a greater extent compared to ST-DFT method. The identification accuracy of the proposed CNBPF and RNBPFMA methods is compared with existing anti-notch filter and RNBPF methods. The results show that proposed methods outperform existing methods in terms of identification accuracy for benchmark data sets.

A substrate integrated folded waveguide (SIFW) H-plane band-pass filter with double H-plane septa based on LTCC

In this paper, a novel substrate integrated folded waveguide (SIFW) H-plane band-pass filter based on low-temperature co-fired ceramic technology (LTCC) is proposed which employs double H-plane septa of a short-ended evanescent waveguide as an impedance inverter. The filter has advantages of convenient integration, compact, low cost, mass-producibility, and ease of fabrication, and it also has frequency responses similar to those of traditional E-plane double-iris waveguide band-pass filters. To validate the new proposed topology, a three-pole narrowband band-pass filter is designed and fabricated using half-wavelength resonators. A comparison between measured results and simulated results shows good agreement.

A miniaturized narrowband bandpass filter with wide stopband using open-loop resonator

To obtain a very good performance of filter in wireless system, a miniaturized microstrip narrowband bandpass filter (BPF) is investigated based on an open-loop resonator analysis. The newly designed BPF has been given with two advantages: one is of a compact size and the other is of a large ratio of the first spurious resonant frequency to the fundamental frequency. Then empirical designing equations of this structure have been discussed. The 3-dB fractional bandwidth and selectivity of the filter can be selected flexibly by using those equations. Finally, a fabricated filter is applied to validating the proposed method. Experimental results are in very good agreement with simulations. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26206

Miniaturized Metamaterial Narrow Bandpass Filters Using CRLH Transmission Line CL-Loaded Approach

In this paper metmaterial narrow band bandpass filter is designed and tested. The filter designed has the following properties, resonant frequency at 900MHz for mobile communications, bandwidth equal to 80MHz, insertion loss lower than -1.3dB, with in-band return loss lower than -16dB, and a wide stopband. The total filter size is about 2cm×2.4cm which is very compact compared to other metamaterial and conventional microstrip filters. This metmaterial narrow bandpass filter is designed based on composite right left handed (CRLH) Transmission line CL-loaded approach. The design steps, simulated and experimental results of the designed filter are presented

Parameter synthesis and design of a novel 14-pole CQ bandpass filter for CDMA2000 applications

Parameter synthesis of a new 14-pole narrowband bandpass filter for CDMA2000 applications is presented, which has two pairs of transmission zeros (TZs) for group delay self-equalization and one pair of TZs at finite frequencies for high selectivity requirement. Cascaded quadruplet structures are used to realize above filtering function TZs. The coupling matrix of the filter is optimized by a cost function on transfer and reflection response using Levenberg-Marquardt algorithm. The simulated and measured results demonstrate the excellent performance of the proposed filter and verify the feasibility of the proposed synthesis procedure. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1190–1193, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25952

A Novel Narrow Passband Millimeter Filter Using Suspended Improved Compact Microstrip Resonant Cell

A novel millimeter wave narrowband bandpass filter using improved suspended compact microstrip resonant cell is proposed in this paper. Compared to the traditional high/low step-impedance filter, the improved CMRC structure possesses good lowpass filter characteristics. Besides, it can shorten the circuit size over 50%. And a suspended CMRC has better filter characteristics of low return loss and sharper stopband rejection than a traditional CMRC. Based on the improved suspended CMRC, a novel millimeter wave narrowband BPF operating at center frequency of 40 GHz is designed and tested. The investigation results show that the BPF has low insertion loss below 1 dB in the narrow passband with a bandwidth of 10% and sharp rejection in the stopband.

A Partial H-plane Substrate Integrated Folded Waveguide (SIFW) Bandpass Filter Based on H-plane Slot

This paper presents a novel partial H-plane bandpass filter based on substrate integrated folded waveguide (SIFW), which employs H-plane slot of open-ended evanescent waveguide as admittance inverter. In order to validate the new proposed topology, a three-pole narrowband bandpass filter is designed and fabricated using standard printed circuit board process. The tapered line is used as transition between SIFW and microstrip for easy integration and measurement. The filter is considerably smaller than its metallic waveguide counterpart. The measured results are in good agreement with simulated results.

Substrate Integrated Folded Waveguide (SIFW) Partial H-Plane Filter with Quarter Wavelength Resonators

In this paper, the design and experiment of a novel substrate integrated folded waveguide (SIFW) partial H-plane bandpass filter, consisting of quarter wavelength resonators, is presented. In the proposed filter, two adjacent quarter wavelength resonators are coupled by connecting an admittance inverter and an impedance inverter alternately. Here, the admittance inverter and impedance inverter are realized by H-plane slot of open-ended evanescent waveguide and H-plane septa of short-ended evanescent waveguide, respectively. In order to validate the new proposed topology, a four-pole narrowband bandpass filter is designed and fabricated using standard printed circuit board process. The tapered line is used as transition between SIFW and microstrip-line for easy integration and measurement. The measured results are in good agreement with simulated results.

Microstrip bandpass filters using cross-shaped triple-mode resonator

Compact three-pole microstrip bandpass filters (BPFs) are presented. The basic block is a triple-mode resonator that consists of a conventional half-wave resonator, a shunt open-circuited stub and a shunt short-circuited stub. The half-wave resonator, the shunt open-circuited stub and the shunt short-circuited stub control each of the first three resonant frequencies. Then, two BPFs using the resonator are designed, fabricated and tested to validate the design concept. For the narrow-band BPF, from 2.4 to 2.6 GHz, the measured return loss is greater than 15 dB and the measured insertion loss is less than 1.7 dB. For the broadband one, from 1.25 to 3.9 GHz, the measured return loss is greater than 12 dB and the measured insertion loss is less than 1.5 dB. The group delay variation is 0.45 ns.

A New Microstrip Bandpass Filter Design Based on Hilbert Fractal Geometry for Modern Wireless Communication Applications

This paper introduces a new microwave narrowband bandpass filter with a miniaturized size as well as adequate transmission and return loss characteristics for use in modern wireless communication systems. The proposed filter design topology is based on a single-mode microstrip resonators constructed in the form of Hilbert fractal geometries of the 2 nd and 3 rd iteration levels. Filter structures have been designed for the ISM band applications at a resonant frequency of 2.4GHz using a substrate with a relative dielectric constant of 10.8 and thickness of 1.27mm.The most effective parameters on filter performance such as edge spacing and stub length variations have been introduced and evaluated . The performance of each of the resulting bandpass filter structures has been analyzed using a method of moments (MoM) based software package, Microwave Office 2007, from Advanced Wave Research Inc. In addition, it has been found that, the bandpass filters based on 3 rd iteration Hilbert geometry show a high degree of 2 nd harmonic suppression which accompanies the performance of most bandpass filter topologies.

Narrowband Elliptic Bandpass Filter Using Dual-Mode Microstrip Square Loop Resonator for WiMax Application

In this paper, a narrowband bandpass filter using dual-mode microstrip square loop resonator is proposed. This structure has a 5.1% fractional bandwidth at 2.3GHz. By using some simple techniques, the optimum results will be achieved. The dual-mode resonator will be produced by adding a square patch inside the loop resonator. The simulation and measurement results are also presented. The filter is fabricated on RT/Duroid 6010 substrate having a relative dielectric constant of 10.2 and 0.635 mm thickness. The final dimension is measured at 19.65 mm 19.65 mm. The minimum measured insertion loss is 1.68 dB and return loss obtained is better than -20 dB, where experimental results and simulated values are in good agreement.

Analysis on IR/TR-UWB Interference against Narrowband Systems

This paper presents the analysis of in-band interference caused by pulse-based ultra-wideband (UWB) systems. The analysis contains both plain Impulse Radio UWB (IR-UWB) and Transmitted Reference UWB (TR-UWB) systems as a source of interference. The supposed victim is a narrowband BPSK system with a band-pass filter. The effect of pulse-based UWB systems is analyzed in terms of bit error rate. The analysis is given in terms of the specific combinations of pulse repetition frequency and center frequency of the narrowband bandpass filter. In those situations, the UWB interference cannot be modeled as a Gaussian noise. It also manifests situations in which the victim is under the severest or the slightest interference from TR-UWB. According to its result, the analysis is validated via simulation.

NOVEL MICROSTRIP HAIRPINLINE NARROWBAND BANDPASS FILTER USING VIA GROUND HOLES

In this paper, we present a novel improved hairpinline microstrip narrowband bandpass filter with via ground holes. The new filter design methodology is derived from conventional hairpinline filter design. This design methodology incorporates use of λ/8 resonators, thereby reducing the size of the filter by 35% as compared to the conventional design. An analysis is presented to show the effects of tap point height and microstrip width on fundamental parameters of filter and subsequent relationships are developed. Through use of via ground holes and a wider microstrip line for resonators, 3 dB Fractional Bandwidth (FBW) less than 2%, Insertion Loss (IL) less than 1.6 dB and Return Loss (RL) better than 40 dB is achieved with midband center frequency 1 GHz. Spurious response suppression is achieved till 3f0. Robustness of this design approach is demonstrated by designing filters on two more substrates having er 2.17 and 9.2. As low as 0.48% FBW was achieved by using different substrates. The design approach is successfully tested for center frequency upto 2 GHz beyond which folding the resonator becomes practically difficult. Finally, a bandpass filter is designed with this design methodology and fabricated using FR4 substrate. S-parameter measurements show a good agreement with the simulated results.

Multiple solutions for the synthesis of microwave filters with predistorted transfer functions

This paper examines the problem of multiple solutions for the synthesis of predistorted transfer functions of microwave narrow-band bandpass filters. The losses in narrow-band bandpass filters affect the flatness of the in-band transfer function and the selectivity sharpness. The predistortion is a synthesis technique used to recover acceptable flatness and selectivity of the transfer function knowing the level of losses. Applying this technique, multiple solutions are available, leading to different circuit realizations and, as a consequence, to different electrical behaviors in presence of losses. In particular, the return loss level in the passband depends deeply on the selected solution. The return loss is generally not a problem in case of IMUX filters but it has generally to be considered in other applications. Simple rules are given in this article in order to select the more appropriate solution in the late case. The theoretical demonstration is illustrated by an example of a 5 pole filter with a predistorted transfer function. The multiple solutions are determined and the effects of losses in term of minimum in-band return loss level are compared for each solution. An experimental model is then used to validate these theoretical results. © 2006 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2007.

ANALYSIS AND APPLICATION OF NOVEL STRUCTURES BASED ON SPLIT RING RESONATORS AND COUPLED LINES

In this paper, novel structures using split ring resonators (SRRs) and coupled lines are proposed and analyzed. SRRs are etched on three different planes and their propagation characteristics are compared. Two compact narrow band band-pass filters based on these structures are designed and their performances are demonstrated by simulated and measured results, which are in good agreement.

Modelling high-order filters in a transient microwave circuit simulator

Transient simulation of narrowband bandpass filters used in microwave circuits is challenging because of matrix ill-conditioning. Here, such filters are modelled as the equivalent discrete-time form developed using a bilinear z-transform. The technique has been implemented in a general purpose transient circuit simulator and validated using a 1.7 GHz 5-section coaxial filter with a 0.9% bandwidth.

Realization of Four Transmission Zeros in a Four-Pole Superconducting Microstrip Filter Using Cross-Shaped Spiral Resonators

The realization of four finite transmission zeros with high-temperature superconducting microstrip narrow-band bandpass filter using four cross-shaped spiral resonators is described for the fully canonical case. The approach is based on the N+2 transversal coupling matrix, which is composed of main direct coupling as well as source/load coupling. The filter, with 0.75% bandwidth, 3.25 MHz, at 408-MHz band, is to be used for a radio astronomy application at Jodrell Bank Observatory, U.K. The measured results match well with both theoretical results and simulated results, except for a small center frequency offset.

A compact bandpass filter with two tuning transmission zeros using a CMRC resonator

This paper presents a new compact, low-insertion loss, sharp-rejection, and narrow-band microstrip bandpass filter (BPF) using a compact microstrip resonant cell (CMRC) as the resonator. Experimental results show that the filter only has 1.3- and 1.5-dB insertion losses when using the symmetrical and asymmetrical CMRC resonators, respectively. The effect of varying the length of the resonator to the notch frequencies of the filter has been studied. Furthermore, due to the CMRC characteristic, the size of this filter is only 0.1/spl lambda//sub g/ by 0.29/spl lambda//sub g/. Based on the same design methodology, a microstrip BPF with a coplanar-waveguide feed is also designed with an increased bandwidth. All the proposed filters have been verified by simulation and measurement with good agreement. These filters are attractive for hybrid microwave integrated circuit and monolithic-microwave integrated-circuit implementation.

A reconfigurable bandpass filter for RF/microwave multifunctional systems

A network prototype suitable for reconfigurable filters with imaginary-axis transmission zeros is presented. The prototype is synthesized using classical cascade synthesis. Reconfiguration of the transmission zeros is implemented entirely by tunable capacitors. The measured performance of a narrow-band reconfigurable bandpass filter realized in a planar combline using varactor diodes demonstrates the principle.

A COMPACT INTEGRATION OF HIGH-TEMPERATURE SUPERCONDUCTING BANDPASS AND BANDSTOP FILTERS

Integration of a high-temperature superconducting (HTS) narrowband bandpass filter and a HTS bandstop filter onto a single piece double-sided YBCO thin film with 0.5mm-thick LaAlO 3 substrate has been carried out. The 8-pole bandpass filter was designed with a fractional bandwidth about 0.8%. A pair of transmission zeros was implemented, showing typical quasi-elliptical function characteristics. The bandstop filter has a high stopband attenuation (~70 dB ) to fulfill the special requirement of potential application in communications. Integration of the two filters was successfully achieved.