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Single-Layer Multi-Via Loaded CRLH Leaky-Wave Antennas for Wide-Angle Beam Scanning with Consistent Gain
摘要： Achieving continuous backward-to-forward wide-angle beam scanning with consistent gain by employing composite right/left-handed leaky-wave antennas (LWAs) is reported. For structural and design simplicity, a single-layer 1-D structure is considered in which each unit cell consists of a patch shorted centrally to the ground plane. It was found that, when using only one via at the center of a unit cell, a continuous beam scan requires a large diameter via when all other parameters remain unchanged. To eliminate this limitation while maintaining a single-layer structure, novel unit cells are proposed using multiple vias in each unit cell. An LWA design for continuous beam scan with three vias in each unit cell is investigated and the results show good performance and design flexibility. A prototype antenna has been realized, and the measured results show that the antenna can scan the radiation beam continuously in a wide range, from ?60° to +66° with a consistent gain. The measured gain variation within the scan range is only 2.9 dB, and the 3dB gain bandwidth is 58.6%.
关键词： single-layer,leaky-wave antenna (LWA),backward and forward,consistent gain,composite right/left-handed (CRLH),Beam scanning
更新于2025-09-23 15:23:52
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TRIPLE-BAND COMPOSITE RIGHT/LEFT HANDED BANDPASS FILTER USING A NEW CIRCULAR INTER-DIGITAL CAPACITOR FOR WIRELESS APPLICATIONS
摘要： In this paper, a compact triple-band bandpass ?lter based on composite right/left handed (CRLH) approach has been proposed. The zeroth order resonance (ZOR) frequency of the designed ?lter can be controlled e?ectively by varying the series parameters. A new circular interdigital capacitor is integrated to provide series capacitance. The number of passbands depends on number of rings of circular interdigital capacitor (C-IDC). In order to validate metamaterial behavior, a dispersion diagram has been plotted for the designed ?lter. The proposed ?lter o?ers measured 3 dB fractional bandwidth of 71% at 1.7 GHz, 24% at 2.9 GHz and 12% at 4.1 GHz as center frequencies. The designed ?lter will be suitable for di?erent wireless applications such as global navigation satellite systems (1.559–1.610 GHz), GSM1800, indoor femtocells (2.5–2.7 GHz), air tra?c surveillance (2.7–2.9 GHz) and ?xed satellite services (3.8–4.2 GHz). The size of the proposed ?lter is 0.13λ0 × 0.11λ0, where λ0 is the free space wavelength at ZOR frequency of 1.7 GHz.
关键词： wireless applications,circular interdigital capacitor (C-IDC),composite right/left handed (CRLH),triple-band bandpass ?lter
更新于2025-09-10 09:29:36
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Fast method for analysing nonlinear composite right/left-handed transmission lines based on finite-difference time-domain method
摘要： In this study, a new finite-difference time-domain (FDTD) scheme is presented for analysing nonlinear composite right/left-handed (CRLH) transmission lines, with reduction of the central processing unit time. A step by step analysis is demonstrated to solve the equations for nonlinear CRLH transmission lines based on the FDTD method. The proposed method is applied to a nonlinear CRLH transmission line as an example and the results are confirmed by those of the conventional FDTD method. The comparisons reveal that the presented solution efficiently decreases by about 82% of the computational time consumption.
关键词： finite-difference time-domain (FDTD),computational time reduction,nonlinear composite right/left-handed (CRLH) transmission lines
更新于2025-09-10 09:29:36
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A compact dual-band bandpass SIW filter using uniplanar combination of the CRLH and resonant type metamaterials
摘要： A new manner of obtaining dual bandpass behaviour in substrate-integrated waveguide (SIW) using a uniplanar combination of composite right/left-handed (CRLH) transmission line and complimentary double split single ring resonator (CDSSRR) is presented and analysed in this paper. The proposed dual band structure has the advantage of miniaturisation due to the presence of both the passbands below the characteristic cuto? frequency of the SIW.A high passband transmission zero overcomes the poor frequency selectivity, and the two resonant frequencies are independently controllable. There are very low insertion losses in both passbands as compared to DGS structures and fabrication simplicity is ensured due to an intact ground. The potential for application of the proposed structure to the design of completely planar miniaturised dual band bandpass metamaterial ?lters has been veri?ed by fabricating a two-stage ?lter based on the proposed combination. The measured results are in good agreement with the simulation results.
关键词： band pass ?lter,complementary split-ring resonators (CSRRs),Metamaterials,Substrate-integrated waveguide (SIW),composite right/left-handed (CRLH),dual-band,miniaturised planar waveguide ?lters
更新于2025-09-10 09:29:36
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POWER PERFORMANCE AND SPURIOUS FREQUENCIES ANALYSIS OF COMPOSITE RIGHT-/LEFT-HANDED (CRLH) DISTRIBUTED OSCILLATORS
摘要： This paper concerns the analysis of the performance of a Composite Right-/Left-Handed (CRLH) distributed oscillator. In order to increase its output power, a modification of the standard configuration is proposed. The basic idea is to combine the signals from the two output ports of the structure by means of a Wilkinson combiner, so obtaining a single output generator. The power performance of the conventional two output oscillator and the power performance of the new configuration are numerically compared by changing the number of employed transistors. The same procedure is adopted to analyze the amplitude of the higher order harmonics in the generated signals as a function of the number of active elements. On the basis of simulated data an increase of the output power, together with a second harmonic reduction, is expected for the single output oscillator with respect to the standard CRLH topology. Experimental results fully confirm these numerical predictions.
关键词： output power,Composite Right-/Left-Handed (CRLH),Wilkinson combiner,harmonics,distributed oscillator
更新于2025-09-09 09:28:46
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PHASE ENHANCEMENT FOR MULTI-RESONANCE COMPACT METAMATERIAL ANTENNAS
摘要： In this paper, a nonlinear phase enhancement of multi-resonance composite right/left-handed unit cell for multi-band antennas is presented. Di?erent antennas with nonlinear enhanced phase which can operate up to ?ve di?erent frequency bands are introduced. Meanwhile, the proposed antennas have compact size so that they can demonstrate size reduction up to 60% compared to conventional patch antennas operating at the same frequencies. The achieved phase enhancement has been validated by comparing two di?erent con?gurations of composite right/left-handed cells. The analysis, electromagnetic full wave simulations and experimental results are discussed. A reasonable agreement is achieved between the measured and simulated results.
关键词： compact metamaterial antennas,phase enhancement,composite right/left-handed (CRLH),multi-resonance,multi-band
更新于2025-09-09 09:28:46
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[IEEE 2018 15th European Radar Conference (EuRAD) - Madrid, Spain (2018.9.26-2018.9.28)] 2018 15th European Radar Conference (EuRAD) - Initial Design of Phase-Frequency Scanned Array Using CRLH Leaky-Wave Antennas
摘要： Initial design of phase-frequency scanned array using composite right/left-handed (CRLH) waveguide leaky-wave antennas (LWAs) is studied in this paper. The array consists of 32 frequency scanning CRLH LWAs that are fed by a phased feed system. Two-dimensional (2D) beam steering capability is achieved in the plane normal to the array aperture and verified by the full-wave simulations. This array is capable of scanning to 61° from backward to forward directions in the frequency-scan plane and 17° in the phase-scan plane. The beamwidth is approximately 2° with ?20 dB sidelobe level (SLL) in the frequency-scan plane and 2.5° with maximum ?10 dB SLL in the phase-scan plane. Compared with traditional 2D scanning array, the feed system of this phase-frequency scanned array can be simplified significantly.
关键词： phase-frequency scanned array,leaky-wave antenna (LWA),two-dimensional (2D) beam steering,composite right/left-handed (CRLH),phased array
更新于2025-09-09 09:28:46