Design Of Wideband Bandpass Filter Research Articles

Application of Cross-Shaped Resonator to the Ultra Wideband Bandpass Filter Design

An ultra-wideband (UWB) bandpass filter (BPF) with two cascaded cross-shaped resonators is proposed and implemented. As the starting work of this letter, a cross-shaped resonator with wide passband is introduced. With the use of even- and odd-mode approach, this initial resonator is characterized and designed to build up a UWB BPF. And then, a cascaded UWB BPF is fabricated to satisfy Federal Communications Commission indoor mask.

Recent Advances in Metamaterial Transmission Lines Based on Split Rings

This paper is focused on metamaterial transmission lines based on split rings. Specifically, the considered lines are those based on the hybrid approach, where complementary split ring resonators (CSRRs) are combined with series gaps and shunt inductive stubs, and those implemented by loading a host line with open split ring resonators (OSRRs) and open complementary split ring resonators (OCSRRs). The dispersion characteristics and the characteristic impedance of such lines, essential for design purposes, are analyzed to the light of the lumped element equivalent circuit models of the lines. Finally, it is shown that hybrid lines are useful for the design of power splitters with filtering capability, and OSRR/OCSRR-loaded lines are of interest for the design of wideband bandpass filters. The achieved performances are satisfactory and device dimensions small.

Analyzing an UWB Bandpass Filter for High Power Applications Using Rectangular Coaxial Cables with Square Inner Conductors

Using the finite element method (FEM) in two dimensions and the CST MICROWAVE STUDIO® (CST MWS) Transient Solver, the electromagnetic (EM) analysis and the design of a novel compact ultra wideband (UWB) bandpass filter using rectangular coaxial cables with square inner conductors, convenient for high power applications, are presented. The design of the UWB BP filter is based on the use of impedance steps and coupled-line sections. The center frequency around 6.85 GHz was selected, the bandwidth is between 3-10 GHz, the insertion-loss amounts to around 0.35 dB and the return loss is found higher than 10 dB in a large frequency range (4-9.5) GHz. The simulated results of stopband performances are better than 15 dB for a frequency range up to 11 GHz. For the selected center frequency and on a substrate with a dielectric constant of 2.03, the rectangular coaxial cables BPF with square inner conductors is only 6.7 × 8.9 × 33.4 mm in size.

Design of LTCC wideband bandpass filter using semilumped resonators

A novel broadband bandpass filter with semilumped resonators based on low-temperature co-fired ceramic (LTCC) technology is proposed. By properly controlling the elements of each resonator, two transmission zeros can be located at both sides of the passband for better selectivity. Moreover, multilayer capacitors are adopted to increase the capacitance without area increment. Measured results show a bandwidth of more than 65%, where the centre frequency is 3.6 GHz.

Side-Coupled Shorted Microstrip Line for Compact Quasi-Elliptic Wideband Bandpass Filter Design

This letter presents a novel structure composed of a shorted quarter-wavelength microstrip line side-coupled to two open-ended stubs. The proposed topology exhibits a quasi-elliptic wideband response with two transmission zeros enhancing the selectivity. To verify the design concept, one filter example has been designed, fabricated and measured. Good insertion/return losses, flat group delay, sharp transition, excellent DC-choked property, simple topology, and compact size are achieved as demonstrated in both simulation and experiment.

Design of a compact wideband bandpass filter

AbstractThis article presents the analysis and design of a compact multi‐layer layer, high selectivity wideband bandpass filter using stub loaded and ‘U’ shaped resonators over a slotted bottom ground plane. While the resonators with folded open circuit stub loadings create the desired bandpass characteristics, the ‘U’ shaped resonators reduce the size of filter. The slotted bottom ground plane is used to enhance the coupling to achieve the desired bandwidth. The proposed filter has been analyzed using circuit model, and the results were verified through full wave simulations and measurements. The fabricated filter is compact and measures a size of 18 mm × 25 mm × 1.6 mm. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1387–1389, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25206

Compact wideband coplanar stripline bandpass filter with wide upper stopband and its application to antennas

A compact wideband coupled-coplanar stripline configuration is presented for a wideband bandpass filter design. Without any increase in the filter size, two stripline shunt open-stubs are introduced to create two transmission zeros to suppress the undesired third harmonic passband of the basic section. Also, a method to control the even- and odd-mode velocities of a coupled-coplanar stripline is described. A prototype bandpass filter having 3 dB fractional bandwidth of 100% at a centre frequency of 3.8 GHz is fabricated on a 0.813 mm thick RO4003 substrate with a dielectric constant of e r = 3.38 with an overall size of 14 × 4.3 mm 2 . Moreover, a differential ultra-wideband (UWB) antenna is designed and the filter is applied in the co-design with the antenna. The resultant compact module provides good radiation characteristics over the 3-5 GHz UWB band and suppresses the other unwanted out-of-band signals.

Design of the Compact Parallel Coupled Wideband Bandpass Filter With Very High Selectivity and Wide Stopband

In this letter, a compact and high performance parallel coupled line wideband bandpass filter (PCL-WBF) with open stubs is designed and implemented on the commercial substrate, RT/Duroid 5880. The PCL-WBF is composed of a one-stage coupled line and two open stubs connected near the input/output ports. The design procedure and limit are discussed in detail. The designed filter was fabricated and measured, showing good characteristics of wide stopband and very high passband selectivity. Measured results also have a good agreement with the simulated results.

A hairpin line wideband bandpass filter design with embedded open stubs

AbstractIn this paper, a compact three‐poles hairpin line wideband bandpass filter with several embedded open stubs to improve the stopband is designed and implemented on print circuit board substrate. This filter at center frequency f0 of 4.25 GHz has presented almost very good measured characteristics, including the bandwidth of 3.1–5.4 GHz (3‐dB fractional bandwidth of 54%), low insertion loss of −0.7 ± 0.4 dB, sharp rejection due to two transmission zeros in the passband edge created by interstage coupling, and wide stopband rejection greater than 15 dB from 5.6 to 11 GHz. Experimental results of the fabricated filter show a good agreement with the predict results. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 934–936, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22302

Microstrip bandpass filters with wide bandwidth and compact dimensions

In this paper, novel microstrip band-pass filters with small dimensions and wide bandwidth are proposed. The devices are based on a new type of lumped resonators recently reported by the authors: double-slit complementary split-ring resonators (DS-CSRRs). Properly combined with grounded stubs, and coupled by means of variable-width transmission-line sections, these resonators provide the necessary bandwidths for the design of wideband band-pass filters in microstrip technology. To illustrate the potentiality of the proposed approach, a 5th-order prototype device with central frequency fo = 3.8 GHz and 30% fractional bandwidth has been designed and fabricated. The measured frequency response reveals that in-band losses are below 1 dB, while the return losses are larger than 15 dB. High-frequency selectivity has been also obtained, with very sharp cutoff in the upper band edge and 40-dB rejection at 2.3 GHz. These wide bands are not easily obtainable with conventional filter implementations. This fact and the small dimensions, derived from the use of DS-CSRRs, make the proposed approach very attractive for those applications requiring wide bandwidths for data transmission. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 46: 343–346, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20982

Design of wide‐band band‐pass filters using discrete‐time domain techniques

AbstractA transmission‐line configuration consisting of equal‐length two‐section open stubs, serial lines, and short stubs is employed to emulate the Z‐domain transfer function of a wideband band‐pass filter. Both mitering and slots are used to reduce the discontinuity effect caused by the abrupt changes of characteristic impedances of transmission lines. A wideband filter is realized in the form of microstrip lines and its frequency responses are measured to validate this novel method. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 264–266, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20438

Wideband bandpass filter design with three-line microstrip structures

A systematic procedure is described for designing wideband bandpass filters based on parallel coupled three-line microstrip structures. It starts with modal analysis of a three-line coupled microstrip circuit. A database of modal eigenvoltage coefficients and modal characteristic impedances for a specified value of substrate ɛr is established. The relation between the circuit parameters of a three-line coupling section and an admittance inverter circuit is derived, so that the filters can be synthesised by a standard procedure. As compared with traditional parallel coupled lines, the proposed three-line design has the following two important features for the design of wideband filters: the tight line spacings of end stages can be greatly relaxed; and the stopband rejections are improved. Four filters with fractional bandwidths from 40% to 70% are fabricated on substrates with low and high dielectric constants. Prediction and measurement results are in good agreement.

LTCC wide-band ridge-waveguide bandpass filters

A ridge-waveguide tap-in coupling structure is applied to the design of wide-band ridge-waveguide bandpass filters using low-temperature cofired ceramic (LTCC). The design is based on rigorous mode-matching modeling, which takes the higher order mode interactions into account. A design procedure is described and design examples are given to demonstrate the features of the proposed coupling structure. A wide-band LTCC ridge-waveguide filter is simulated and successfully built. Good experimental results are obtained.

The Design of Arithmetically Symmetrical Band-pass Filters

A method is described for the (insertion loss) design of wide-band band-pass filters to exhibit arithmetically symmetrical characteristics. The method consists of a periodic transformation of the frequency variable, truncation of the resulting infinite product in the characteristic function, and finally, correcting the truncation error by a compensating function. The last step involves a certain amount of numerical or graphical approximation, but the required accuracy is usually quite easy to satisfy by elementary methods. As a special case, the design of constant group delay band-pass filters is also described.