Simplified Composite Right/left-handed Research Articles

An improved simplified composite right‐/left‐handed zeroth‐order resonator and its application to design a compact microstrip bandpass filter with enhanced upper stopband

AbstractAn improved simplified composite right‐/left‐handed (SCRLH) zeroth‐order resonator (ISZOR) is introduced, comprising two lateral parallel capacitors and a centred T‐type inductor circuit. Starting from the lumped circuit of the ISZOR, its miniature microstrip layout can be generated with on more than three times full‐wave simulations by virtue of the implicit space mapping technique. Multi‐solutions of the microstrip ISZOR with identical fundamental mode are obtained by sweeping key physical and electrical parameters, uncovering the relationship among physical sizes, resonant modes, unloaded quality factors and circuit elements. A three‐pole microstrip Chebyshev bandpass filter (BPF) with ultra‐wide upper stopband is further designed. By choosing the constituent ISZORs with identical base frequency but different higher resonant frequencies and applying the over‐coupled I/O terminals, wideband spurious response suppression in the upper stopband is achieved. The target BPF centers at 3.1 GHz with a relatively bandwidth of 5%, which is optimised through a customised aggressive space mapping iterative process. The optimal BPF layout dimensions are automatically obtained with just a few time‐consuming full‐wave simulations. A prototype measurement shows the BPF features good bandpass selectivity in a simple and easy‐to‐fabricate structure, with a transversal size reduction of more than 65% compared to a former counterpart and a rejection level better than 15 dB over 40.0 GHz.

Improved SCRLH ZOR‐based compact microstrip bandpass filter with wide upper stopband

AbstractA novel compact microstrip bandpass filter (BPF) based on an improved simplified composite right‐/left‐handed (SCRLH) zeroth‐order resonator (ZOR) is presented in this paper. The improved SCRLH ZOR (ISZOR) can substantially simplify the filter configuration and shrink the filter size as well as ensure a wide upper stopband. A certain orientation of two ISZORs allows a larger gap to produce the specified interstage capacitive coupling, easing the requirement for fabrication precision. Starting from the purely lumped circuit model, the microstrip ISZOR is efficiently generated by utilizing the implicit space mapping technique, with which the microstrip BPF is then constructed and optimized by the Nelder–Mead simplex algorithm. A three‐pole filter with a center frequency of 3.1 GHz and a relative bandwidth of 5% is exemplified to illustrate the design process. The measurement shows that the filter is of good bandpass selectivity, with a transversal size reduction of more than 64% compared to a former counterpart and a rejection level better than 30 dB up to 11.76 GHz (close to 4f0).

Compact Wideband Dual-Frequency Antenna Based on a Simplified Composite Right/Left-Handed Transmission Line with Hilbert Curve Loading

This paper addresses the issues of low bandwidth, gain, and efficiency of miniaturized microwave antennas by proposing a novel wideband dual-frequency coplanar waveguide antenna design based on a simplified composite right/left-handed (SCRLH) transmission line structure with Hilbert curve loading. The multifrequency characteristics of the SCRLH transmission line structure are evaluated theoretically, and the antenna parameters promoting bandwidth broadening under zeroth-order resonance (ZOR) and first-order resonance (FOR) mode operation are evaluated. The bandwidth broadening in the ZOR and FOR modes is accordingly revealed to be independent of the antenna length, and the structure therefore facilitates wideband operation under miniaturization. Finally, the dual-frequency ZOR and FOR mode antenna design with center frequencies of f0 = 1.865 GHz and f1 = 2.835 GHz is validated via simulation, and the performance of a compact prototype antenna is evaluated experimentally. The −10 dB return loss bandwidths at f0 and f1 are 187 MHz (from 1.773 GHz to 1.96 GHz) and 368 MHz (from 3.002 GHz to 3.37 GHz), and the corresponding relative bandwidths are 10.1% and 11.5%, respectively. The experimentally measured peak gains and radiation efficiencies at f0 are 1.54 dB and 81.3%, respectively, and those at f1 are 1.71 dB and 74.2%, respectively.

Design and Analysis of Compact Microstrip UWB Band pass Filter with a Notched Band Using Defected Microstrip Structure

Abstract This paper presents design of ring–shaped wide-band band pass filter with notched band. The ring –shaped UWB BPF using a simplified composite right/left handed (SCRLH) resonator. The narrow band notch responses produced by DMS (Defected trip Micros Structure) was introduced at a frequency of 5.2 GHz in order to reject any undesired signals which may interfere with the wideband communication systems. This band pass filter is designed to pass the UWB signals between 2.9 GHz to 10.2GHz and to eliminate WLAN signal (5.2 GHz). The resulting filter has been found to possess a compact size of 20mm×30mm. This design is simulated by CST microwave software based on the Finite Integration Technique (FIT).

UWB Filtering Power Divider with Two Narrow Notch-bands and Wide Stop-band

AbstractA compact filtering ultra-wideband (UWB) microstrip power divider (PD) with two sharply rejected notch-bands and wide stopband is analyzed and designed in this paper. The proposed UWB PD is based on a conventional Wilkinson power divider, while two stub loaded resonators (SLRs) are coupled into two symmetrical output ports to achieve a bandpass filtering response. The simplified composite right/left-handed (SCRLH) resonators are employed to generate the dual notched bands. Defected ground structure (DGS) is introduced to improve the passband performance. Good insertion/return losses, isolation and notch-band rejection are achieved as demonstrated in both simulation and experiment.

Wide-Band Planar Balun Based on Simplified Composite Right-Left-Handed Structure

Wide-band planar microstrip balun implemented with simplified composite right/left-handed (SCRLH) structure is presented in this letter. The proposed balun consists of a wide-band Wilkinson power divider and a broadband 180° phase shifter based on SCRLH structure. The new design was simulated and validated by the measurement. In the experimental results, within the frequency range from 3.1 to 8.3 GHz (91.2%), the measured return losses of the unbalanced and balanced ports are greater than 10 dB, and the balanced ports isolation is below 15 dB. The measured amplitude and phase difference between the two balanced ports are within ±0.6 dB and ±50, respectively, over the operating frequency band.

Design of a new bandpass filter using S‐CRLH SIRs

ABSTRACTA new quad‐band bandpass filter using simplified composite right/left handed (S‐CRLH) stepped impedance resonators (SIR) is proposed in this article. The filter uses the zeroth and first‐order resonance of the two S‐CRLH SIRs and achieves insertion loss of 0.93, 0.79, 1.14, 0.64 dB at 5.9, 6.6, 9.3, and 9.7 GHz, respectively. It has the advantages of low in‐band insertion loss, good out‐band rejection, and compact size. Good agreement has been achieved between simulation and measurement results. It has been demonstrated by the results for the first time that the zeroth‐order resonance mode of S‐CRLH transmission lines can also be ultilized in the multipassband (over three passbands, not just mono‐ or dual‐passband) filter application to achieve good performance. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:265–268, 2014

A Bandpass Filter Based on Novel SCRLH Transmission Line Structure

In this paper, a novel simplified composite right/left handed (SCRLH) transmission line (TL) structure is proposed.The dispersion and impedance characteristics of the novel structure are first analysed based on Bloch-Floquet theory, which shows that the attenuation constant keeps zero with a relatively smooth characteristic impedance distribution within the passband and that the characteristic impedance is purely imaginary with the inhibition of the electromagetic wave propagation outside the passband.

A novel tri-band band-pass filter using combined simplified CRLH and right-handed SIRs

In this study, a novel tri-band band-pass filter using combined simplified composite right-/left-handed (CRLH) and right-handed (RH) stepped impedance resonators (SIR) is presented. This filter utilizes the zeroth order resonance of the SIRs in the CRLH region and RH resonance in the RH region to produce three different passbands. The proposed filter is simulated and measured, and measurement results match well with simulation ones. Good properties of low in-band insertion loss, good out-band rejection, and compact size have been achieved and verified, and it can be easily applied in the microwave circuits and wireless communication systems.

COMPACT DUAL-BAND 90° COUPLERS WITH CUSTOMIZABLE POWER DIVISION RATIOS UTILIZING SCRLH TRANSMISSION LINES

Novel dual-band 90◦ couplers with arbitrary power division ratios using simplified composite right-/left-handed (SCRLH) transmission lines (TLs) are proposed. With a degree of freedom in the structural parameters, a SCRLH stub can easily be tailored to imitate a conventional 90◦ section at two arbitrary frequencies with different characteristic impedances, making the resulting couplers with customizable power division ratios, as well as ensuring the size miniaturization and element realizability. To validate our idea, 90◦ couplers operated at 2.45/5.2 GHz with various power division ratios are designed and fabricated using microstrip technology. Good agreement is achieved between the simulated and measured results, justifying that the SCRLH configuration provides a new way of implementing compact dual-band 90◦ couplers with arbitrary power split ratios.

Design of compact UWB bandpass filter with dual notched bands using novel SCRLH resonator

AbstractIn this letter, a novel and compact ultra‐wideband (UWB) bandpass filter with dual sharply notched bands based on a novel simplified composite right/left‐handed (SCRLH) resonator is presented.The basic UWB BPF comprises a stub‐loaded multiple‐mode resonator and two interdigital coupled lines. The SCRLH resonator is studied and introduced to obtain the dual notched bands. The proposed filter is simulated, fabricated, and measured, with good agreement between the simulated and measured results. The two notched bands of the BPF centered at 5.8 and 8.7 GHz have 10‐dB fractional bandwidths of about 2.6 and 3.4%, respectively. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1506–1508, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26832

A Novel Ring Slot Resonator UWB Bandpass Filter with Two Notch-Bands

A novel ultra-wideband(UWB) bandpass filter with dual notch-bands and wide stop-band is proposed. The designed UWB BPF is cascading a coupled simplified composite right-left-handed (SCRLH) resonator and a ring slot resonator (RSR). The SCRLH resonator creates two different notch-bands. And the RSR unit suppresses the higher-order harmonics at the upper stop-band. The UWB BPF demonstrated good insertion/return losses and out-of-band rejections in simulation.

BANDPASS FILTER USING MINIATURIZED SCRLH MZOR

A highly miniaturized simplified composite right/left handed (SCRLH) mushroom zeroth-order resonator (MZOR) is proposed for bandpass filter (BPF) design. By introducing the U slot etched around the metallic via, more flexible selection of the shunt inductance value can be achieved compared with the original one. As the length of U -slot increased, zeroth-order resonant frequency of the MZOR decreased, even 88% size reduction can be achieved. Finally, a bandpass filter based on the proposed MZOR is designed, fabricated and measured. The simulated and measured results are presented and good agreement is obtained.

Compact UWB Bandpass Filter With Dual Notched Bands Based on SCRLH Resonator

This letter presents a novel ultra-wideband (UWB) band-pass filter (BPF) with dual sharply rejected notch-bands based on a simplified composite right/left-handed (SCRLH) resonator. The basic UWB BPF is comprised of four folded shunt quarter-wavelength short-circuited stubs separated by connecting lines with length of λg0/4 and λg0/2, respectively. The SCRLH resonator is studied and employed to introduce the dual notched bands. Good insertion/return losses are achieved as demonstrated in both simulation and experiment.

UWB bandpass filter with two notch-bands based on SCRLH resonator

A compact ultra-wideband (UWB) bandpass filter (BPF) with two sharply rejected notch-bands and wide stop-band is presented. The proposed UWB BPF is realised by cascading two interdigital hairpin resonator units, a coupled simplified composite right-left-handed (SCRLH) resonator, a semi-circle defected ground structure (S-DGS) and a semicircle stepped-impedance shunt stub (S-SISS). The SCRLH resonator is studied and employed to introduce two notched-bands. An S-DGS and an S-SISS are cascaded to suppress the spurious in the stop-band. Good insertion/return losses and high out-of-band rejections are achieved as demonstrated in both simulation and experiment.

Miniaturized microstrip bandpass filter using coupled SCRLH zeroth‐order resonators

AbstractA novel miniaturized microstrip bandpass filter (BPF) has been proposed by using coupled simplified composite right/left‐handed (SCRLH) zeroth‐order resonators (ZORs). The SCRLH ZOR consists of microstrip high/low‐impedance short‐line elements, grounded stub, and transmission line sections. Being one of the artificial metamaterials, the SCRLH ZOR resonates when the phase constant equals to zero. Compared with the conventional half‐wavelength resonator, the superiority of the proposed ZOR mainly lies in its compact size. In addition, it is easy to tune the zeroth‐order resonant frequency, thanks to its simple structure and easy fabrication. In this article, the performance and design of the novel ZOR is first studied in detail. Then, the ZOR is exploited to devise a three‐order Chebyshev coupled microstrip BPF. Different coupling schemes are adopted, including interdigital capacitor coupling for the interstages and aperture‐backed dual‐finger parallel‐coupled line structures at the terminals, thus, the specified coupling strengths can be conveniently satisfied. Finally, a prototype device filter operative at S‐band is provided to illustrate the proposed techniques. Salient feature of the size reduction of the novel filter is achieved (more than 70%) when compared to a conventional structure. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2985–2989, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24808

SCRLH TL Based UWB Bandpass Filter with Widened Upper Stopband

A planar ultra-wideband (UWB) bandpass filter with widened upper stopband is presented in this paper. The filter is constructed by adopting a novel simplified composite right-/left-handed (SCRLH) transmission line (TL) structure. The fundamental characteristics of the SCRLH TL are first analyzed, and then its corresponding microstrip implementation is utilized to realize the practical UWB bandpass filter. However, thanks to the inherent parasitic effects of the microstrip quasi-lumped elements at high frequency, a spurious passband comes into being around 15.1 GHz. With an aim to broaden the bandwidth of the upper stopband, two embedded open-circuited stubs are introduced in the input and output feeding lines, which can effectively suppress the spurious passband, thus generating a widened upper stopband.

Arbitrarily dual-band components using simplified structures of conventional CRLH TLs

Microwave components with nonlinear phase responses are developed using a simplified composite right/left-handed (CRLH) transmission-line (TL) structure without the series capacitance or the shunt inductance. Using such a simplified CRLH structure, arbitrarily dual-band microstrip components have been realized in compact sizes such as a quarter-wavelength short-circuited stub and dual- band branch-line couplers. Simulation and measurement results are given to demonstrate the efficiency and good performance of the proposed components. For the quarter- wavelength short-circuited stub based on the simplified CRLH-TL structure without the series capacitance, it has been shown that the insertion loss is less than -0.1dB. For the arbitrarily dual-band branch-line coupler, experiment results exhibit that S/sub 21/ and S/sub 31/ are larger than -3.6dB, the isolations are smaller than -30dB, the return losses are smaller than -20dB, and the phase differences are within 90/spl deg//spl plusmn/1.8/spl deg/.