Microstrip Stepped-impedance Resonator Research Articles

Novel Stepped Impedance Microstrip Bandpass Filters for Radar Applications

In this paper, the design and realization of A Novel Microstrip Stepped Impedance Resonator Bandpass Filters with two selected center frequencies (f0) 12GHz and 16GHz presented. For The design of Band pass Filters “Rogers 6035HTC" substrate material with relative dielectric constant of 3.55, Standard thickness of 0.020” (0.508mm), thickness of pec is 0.035mm and simulated on High Frequency System Simulator (HFSS). Both the designed filters performances are discussed and compared with literature. The designed Stepped Impedance microstrip BPFs have insertion loss of <1dB with the optimal average performance of 37% and 32% FBW, and return losses are 47 dB and 32dB, which is reported better when compared with the reference designs.

Flexible Wearable Composite Antennas for Global Wireless Communication Systems.

Although wearable antennas have made great progress in recent years, how to design high-performance antennas suitable for most wireless communication systems has always been the direction of RF workers. In this paper, a new approach for the design and manufacture of a compact, low-profile, broadband, omni-directional and conformal antenna is presented, including the use of a customized flexible dielectric substrate with high permittivity and low loss tangent to realize the compact sensing antenna. Poly-di-methyl-siloxane (PDMS) is doped a certain proportion of aluminum trioxide (Al2O3) and Poly-tetra-fluoro-ethylene (PTFE) to investigate the effect of dielectric constant and loss tangent. Through a large number of comparative experiments, data on different doping ratios show that the new doped materials are flexible enough to increase dielectric constant, reduce loss tangent and significantly improve the load resistance capacity. The antenna is configured with a multisection microstrip stepped impedance resonator structure (SIR) to expand the bandwidth. The measured reflection return loss (S11) showed an operating frequency band from 0.99 to 9.41 GHz, with a band ratio of 146%. The antenna covers two important frequency bands, 1.71–2.484 GHz (personal communication system and wireless body area network (WBAN) systems) and 5.15–5.825 GHz (wireless local area network-WLAN)]. It also passed the SAR test for human safety. Therefore, the proposed antenna offers a good chance for full coverage of WLAN and large-scale development of wearable products. It also has potential applications in communication systems, wireless energy acquisition systems and other wireless systems.

High selectivity wideband 180° phase shifters with the functionality of vertical transition

AbstractIn this paper, a high selectivity wideband 180° phase shifter (PS) with the functionality of vertical transition is presented. The whole circuit is realized based on the hybrid microstrip/slotline (SL) structure. By introducing the short-circuited microstrip stepped-impedance resonators, two transmission zeros are created to improve the selectivity of the PS. With the SL in the center ground layer, a frequency independent 180° PS can be obtained. The even/odd-mode equivalent circuits of the proposed PS are analyzed to guide the design. Finally, a practical wideband 180° PS with high filtering selectivity is designed and fabricated to verify the design theory.

A Microstrip Stepped-Impedance Resonator Bandpass Filter Based on Inductive Coupling

Abstract A simple and successful design for a microstrip stepped-impedance resonator (SIR) bandpass filter (BPF) based on inductive coupling is presented. It is well known that SIRs are used to shift or suppress the higher order frequencies. In order to achieve compact circuit size, a perceptual stepped-impedance resonator is utilized. Based on theoretical analysis, this resonator can shift the spurious frequency to 3.8f0. The experimental results show good agreement with theory and simulations.

A Novel Cross-Coupled Filter Through Mixed Coupling Path with Multiple Tunable Transmission Zeros

A novel bandpass filter with multiple transmission zeros using a mixed-coupling microstrip stepped-impedance resonator is proposed and investigated in this article. A microstrip with a grounded via hole is added in the middle of the improved microstrip stepped-impedance resonator; the coupling gap and the grounded via hole act as the electric and magnetic coupling, respectively, by which additional transmission zeros can be generated near the passband. Based on the proposed filter topology, a fourth-order bandpass filter with five transmission zeros is fabricated and measured. Compared with a conventional cascaded-quadruplet filter, the novel designed filter has sharper rejection with a symmetrical response and more compact size. Moreover, the proposed idea leads to a new solution to decrease size as well as increase the capability of the conventional stepped-impedance resonator filters.

Novel hybrid resonant structures and its applications in compact multiband bandpass filters

A novel hybrid resonant structure which can realize compact multiband bandpass filters BPFs and its design method are proposed in this article. The hybrid resonant structure is a dual-plane structure which is an effective combination of a pair of microstrip stepped impedance resonators on the top layer and two nested dual-mode defected ground structure resonators on the bottom layer. A triband BPF adopting this hybrid resonant structure was presented which was operating at 2.4/5.7 GHz wireless local area network application and 3.5 GHz worldwide interoperability for microwave access application. The size of this filter is only 0.14λ0 × 0.11λ0. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:690-696, 2014.

DESIGN FILTERS USING TUNABLE E-SHAPED DUAL-MODE RESONATORS FOR LOWER-ULTRA-WIDEBAND AND UPPER-ULTRA-WIDEBAND APPLICATIONS

Two ultra-wideband (UWB) microstrip bandpass fllters (BPFs) are proposed by using tunable E-shaped dual-mode microstrip Stepped-Impedance Resonator (SIR). For the lower band fllter measurement results show there is a passband of 3.1GHz to 5.2GHz and its 3dB fractional bandwidth is 51%. The UWB upper band fllter may be obtained by tuning E-shaped SIR. The measurement results show there is a passband of 6GHz to 10.6GHz and its 3dB fractional bandwidth is 55%. Compared with the similar investigation using the cascade of electromagnetic band gap (EBG)-embedded multiple-mode resonator (MMR) and fork resonator, the proposed approach has some advantages, such as easier adjustment of bandwidths, better passband performances and smaller size etc..

Miniaturized Composite Right/Left-Handed Stepped-Impedance Resonator Bandpass Filter

In this letter, a microstrip Stepped Impedance Resonator (SIR) bandpass filter (BPF) based on Composite Right/Left-Handed (CRLH) transmission lines is presented for the first time. Supported by theory, full-wave simulations and measurements, operational principle of the filter is explained and results are analysed. Also, comparison is made between this filter and its conventional right-handed (RH) counterpart. For the same centre frequency, fractional bandwidth and stop-band attenuation, the CRLH SIR BPF presented here proves to surpass its conventional counterpart in terms of size, being about 80% smaller, without degradation of performance. The CRLH SIR BPF is also significantly more controllable in its dimensions and response due to the fact that more elementary parameters are available in CRLH configuration.

Miniaturized Bandstop Frequency-Selective Structure Using Stepped-Impedance Resonators

This letter describes a miniaturized bandstop frequency-selective structure (FSS) based on the stepped-impedance resonator (SIR). The FSS consists of a two-dimensional periodic array of vertical microstrip SIRs for thickness reduction. A shunt capacitor connecting the SIR center and ground is employed to widen the operating bandwidth and to improve the quasi-elliptic filtering response. It is shown that more than 40% thickness reduction of the FSS can be realized by choosing a small impedance ratio of the SIR, and a steep quasi-elliptic bandstop filtering performance is achieved by adjusting the value of the shunt capacitor. As an example, a prototype of the proposed FSS is designed, fabricated, and tested. The good agreement between simulated and measured results verifies the design concept of the miniaturized FSS.

New dual-band bandpass filter design based on slotted ground structures

Two dual-band bandpass filters featuring flexible frequency choice and compact size are proposed using two kinds of resonators.One is based on two pairs of different dimensional slotted ground resonators; another is based on a pair of slotted ground resonators and a microstrip-stepped impedance resonator. Unlike traditional filters, the harmonics of slotted ground resonators forming the lower passband are tuned to higher frequencies; the resonators forming the lower and upper passband lie at the two sides of signal line, the two passbands can be adjusted to the desired values with expected bandwidth by changing the sizes of the resonators independently. The interactions between them are minor. The proposed filters do not need extra impedance matching network unlike traditional dual-band filters and with the ground plane efficiently used, they are more compact in structure. Both filters are optimized with jumping genes evolutionary algorithms for multiobjectives, such as low-insertion loss, suitable bandwidth, and good stopbands. Two optimized bandpass filters were also implemented. Simulation and measurement results are performed to verify their good characteristics. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26028

Reconfigurable bandpass filter based on net-type stepped-impedance resonator

A novel reconfigurable bandpass filter based on a net-type stepped-impedance resonator (SIR) is investigated. This work aims to demonstrate a new approach to implement the reconfigurable centre frequency of the bandpass filter. The approach controls the ratio of the two characteristic impedances of a quarter-wavelength microstrip SIR with pin diodes. The proposed filter is designed to be reconfigured in the three centre frequencies: 720 MHz, 900 MHz, 1 GHz. A comparison between measured and simulated results shows good agreement.

Fabrication-Tolerant Microstrip Quarter-Wave Stepped-Impedance Resonator Filter

The etching error causes serious frequency drift of a microstrip stepped-impedance resonator (SIR). This paper proposes a novel microstrip quarter-wave SIR structure, which is insensitive to fabrication tolerances. Inserting several ground strips in the low-impedance section of the resonator keeps the impedance ratio almost constant in spite of inaccurate fabrication. As an additional benefit, the resonator size would be miniaturized because the characteristic impedance of the microstrip line in the low-impedance section is mainly controlled by the signal strips and the inserted ground strips in a coplanar manner. The concepts and characteristics of this modified resonator structure are discussed in detail. The filters constructed by the conventional microstrip SIR were also designed and fabricated at the same frequency band to compare with the proposed ones. Measured results show that each proposed filter has compact size, wide stopband, and high tolerance to fabrication errors. Two four-pole cross-coupled filters were designed and fabricated to demonstrate the feasibility.

A COMPACT COMPOSITE BROAD STOP-BAND ELLIPTIC-FUNCTION LOW-PASS FILTER FOR ULTRA WIDE-BAND APPLICATIONS USING INTERDIGITAL CAPACITORS

A COMPACT COMPOSITE BROAD STOP-BAND ELLIPTIC-FUNCTION LOW-PASS FILTER FOR ULTRA WIDE-BAND APPLICATIONS USING INTERDIGITAL CAPAC-ITORSM. NosratiFaculty of EngineeringDepartment of Electrical EngineeringIlam Azad UniversityIlam, IranT. FarajiFaculty of EngineeringDepartment of Electrical EngineeringKermanshah Azad UniversityKermanshah, IranZ. AtlasbafFaculty of EngineeringDepartment of Electrical EngineeringTarbiat Modares UniversityTehran, IranAbstract—A compact composite ultra wide-band elliptic-functionlow-pass filter is introduced by combining in cascade a microstripstepped-impedance resonator using interdigital capacitor and anadmittance inverter. A triple cascade low-pass filter is designed,analyzed and tested with this technique accompanied by its equivalentcircuit model. This composition acts similar to a composite filter withdesired attenuation and matching properties in order to obtain widebandwidth and broad stop-band. The proposed low-pass filter featuresthe sharpness of cut off frequency, low insertion loss, enhancement ofbandwidth up to X-band frequencies and very compact size.

Compact Dual-Band Filter Using Defected Stepped Impedance Resonator

This letter presents a novel approach for designing a dual-band bandpass filter by using defected stepped impedance resonator (DSIR). The resonant frequency of the DSIR is found to be much lower than that of the conventional microstrip stepped impedance resonator (SIR), which reduces the circuit size effectively. Two types of second-order DSIR microstrip bandpass filter operating at 1.85 and 2.35 GHz, respectively, are well designed according to the classical theory of coupled resonator filter. Then they are combined to construct a compact dual-band filter with a common parallel microstrip feed line, the measurement results of the fabricated filter have a good agreement with the simulation.

Novel Dual-Band Filter Incorporating Defected SIR and Microstrip SIR

This letter presents a novel approach to design dual-band bandpass filter by using defected stepped impedance resonator (DSIR) and microstrip stepped impedance resonator (MSIR). A pair of MSIRs on the upper plane forms a cross coupled filtering passage, and a pair of DSIRs at the lower plane constructs a linear phase filtering passage. Both of them are fed by a common T-shaped microstrip feed line with source-load coupling. Then they are directly combined to construct a compact dual-band filter with two passbands centering at 2.35 GHz and 3.15 GHz, respectively. The measurement results agree well with the full-wave electromagnetic designed responses.

Microstrip Bandpass Filters with Reduced Size and Improved Stopband Characteristics Using New Stepped-Impedance Resonators

This paper proposes a new microstrip stepped-impedance resonator (SIR) used for bandpass filters with reduced size and improved stopband characteristics. A comprehensive treatment of both ends of the resonator with loaded triangular and rectangular microstrips is described. The design concept is demonstrated by two filter examples including four-resonator parallel-coupled Chebyshev bandpass and compact four-resonator cross-coupled elliptic-type filters. These filters are not only compact size due to the slow-wave effect, but also have a wider upper stopband resulting from the resonator bandstop characteristic. The filter designs are described in details. The simulated and experimental results are demonstrated and discussed.

Realization of Attenuation Poles, Spurious Resonance Suppression and Size Reduction by Microstrip SIR Loaded with Dielectric Rods

Characteristics of a class of stepped-impedance resonators (SIRs) which is loaded with two dielectric rods, are investigated by a Finite-Difference Time-Domain (FDTD) method. Dielectric rods to be inserted between a strip conductor and the ground plane have higher relative permittivity than that of the substrate. When a tapped half-wavelength (λ/2) microstrip resonator is loaded with two dielectric rods, the electric length of a loaded A/2 resonator becomes longer than λ/2, which makes its fundamental resonant frequency (f' r ) to be generated on the region lower than that of an unloaded A/2 resonator (f r ) and its first spurious response (f sp1 ) is generated on the region higher than 2f' r . Therefore, to shift f' r back to f r , the resonator's length is to be reduced, and this, in turns, suppress the spurious responses. Then, the resonant characteristics of an SIR employing the proposed method has also been investigated, and it is found that this is capable of suppressing the spurious responses in wideband together with an attenuation pole in the stopband, and of further reducing the resonator's length. Therefore, wide exploitation of the presented method can be expected in the filter design based on the LTCC technique.

Microstrip stepped‐impedance resonator bandpass filter with over‐coupling structure for suppression of harmonic response

AbstractThis paper describes the microstrip stepped‐impedance resonator (SIR) bandpass filter with an over‐coupling structure for the suppression of spurious response at twice the center frequency (2f0). In addition, the tapped I/O is used in the filter to create the extra transmission zeros to further improve stopband rejection. First, conventional approximate design formulas of microstrip SIR are also presented to predict the filter performance, and then the EM simulation is used to optimize the filter performance. The designed bandpass filters have a wide upper stopband with satisfactory attenuation levels. The experimental results of the two designed filters are in good agreement with the theoretical predictions and simulated results. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 41: 130–133, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20069

Aperture-backed microstrip stepped impedance resonator with ultra-broad rejection bandwidth

An improved microstrip stepped impedance resonator (SIR) with backed aperture is developed for the purpose of effective suppression of multiple spurious resonances. By backing the aperture at the centre and widening the strip widths at two sides, this novel SIR with miniaturised size achieves the ultra-broad rejection bandwidth of 4.0 to 17.6 GHz, as exhibited in the simulated and measured results.

Microstrip stepped impedance resonator bandpass filter with an extended optimal rejection bandwidth

Bandpass filters with an optimal rejection bandwidth are designed using parallel-coupled stepped impedance resonators (SIRs). The fundamental (f/sub o/) and higher order resonant harmonics of an SIR are analyzed against the length ratio of the high-Z and low-Z segments. It is found that an optimal length ratio can be obtained for each high-Z to low-Z impedance ratio to maximize the upper rejection bandwidth. A tapped-line input/output structure is exploited to create two extra transmission zeros in the stopband. The singly loaded Q(Q/sub si/) of a tapped SIR is derived. With the aid of Q/sub si/, the two zeros can be independently tuned over a wide frequency range. When the positions of the two zeros are purposely located at the two leading higher order harmonics, the upper rejection band can be greatly extended. Chebyshev bandpass filters with spurious resonances up to 4.4f/sub o/, 6.5f/sub o/, and 8.2f/sub o/ are fabricated and measured to demonstrate the idea.