Composite Right/left-handed Transmission Line Research Articles

An impedance matching section based on composite right/left‐handed transmission line model in viewpoint of phase shift and noise figure

AbstractIn this paper, a genetic‐based synthesis approach for an impedance matching section based on a composite right‐/left‐handed (CRLH) transmission line model called CRLH transmission line impedance matching section (CRLHTLIMS) in viewpoint of transmission phase shift and noise figure is newly presented. To find the unknown values of right‐/left‐handed inductances and capacitances of a CRLHTLIMS, a type of global optimization algorithm called continuous parameter genetic algorithm is used. The length, transmission phase shift, and noise figure of the CRLHTLIMS are computed by using simple equations. Different examples for a uniform CRLHTLIMS are given. According to the results, this approach is an easy and effective way for the synthesis of transmission line impedance matching sections in viewpoint of transmission phase shift and noise figure.

Nonlinear Time-domain signal and noise analysis of an active CRLH transmission line for millimeter-wave frequencies

In this paper, time domain signal and noise behavior of an active CRLH transmission line was investigated in the nonlinear regime at millimeter wave frequencies. In this structure, the transistor is considered as three coupled transmission lines and all three drain,gate and source lines are CRLH transmission lines. The left-handed element values for the active CRLH transmission line are calculated in such a way that the phase cancellation effect and dispersion of the CRLH transmission line are reduced. In order to model this active CRLH transmission line, with the assumption of wave propagation in the form of Quasi-TEM, the distributed modeling method is used to extract stochastic telegraphic equation (STE) in the non-linear regime. To model noise sources in the non-linear regime, the Wiener process and modulation functions have been used to model white noise in the nonlinear regime and in the time domain. By applying the finite integration method to stochastic telegraphic equation, the behavior of the signal and noise of the active structure CRLH has been compared with a line of active structure RH and the obtain results of the numerical method have been verified with the results of the Agilent ADS software.

A Wide Stopband Dual-notched Bands UWB Filter Based on A Novel Composite Right/left Handed Transmission Line

Background:: As one of the key components of ultra-wideband (UWB) system, UWB filter has important research significance. However, the current UWB filter still has the problem of a narrow stopband and cannot suppress the interference signals in the passband Objective:: In this paper, a novel UWB bandpass filter is proposed, which has wide stopband characteristics and good out-of-band rejection performance and implements a notch function for the WLAN band and the X satellite communication band in the passband to improve the antiinterference performance. Method:: The filter adopts a novel composite right/left handed transmission line (CRLH-TL) structure to realize the passband characteristics with low insertion loss (< 0.8dB). The anticoupled line structures generate two transmission zeros (TZs) in the upper stopband, which improves the upper stopband performance of the filter. The short circuit step impedance resonators (SIRs) and the asymmetric coupling structure generate a notched band in the passband respectively. Results:: The simulated and measured results show that the 3dB passband range is 3.4-11.0 GHz, the out-of-band rejection is more than 20 dB in the stopband range of 12.8-28 GHz, and the dualnotched bands are located at 5.86 GHz and 8.0 GHz respectively. The measured results are basically consistent with the simulated results. Conclusion:: Compared with the existing filters, the proposed filter has outstanding advantages and has a wide range of application prospects in the field of indoor UWB positioning system.

Metamaterial Inspired Varactor-Tuned Antenna with Frequency Reconfigurability and Pattern Diversity.

A metamaterial-inspired varactor-tuned antenna with frequency reconfigurability and pattern diversity is designed. Two different versions of a reconfigurable structure are integrated into a single antenna to excite two different orthogonal patterns, which realizes pattern diversity for MIMO applications. The outer annular Composite Right-/Left-Handed Transmission Line (CRLH-TL) works at the 1 mode and provides a broadside pattern, and the inner circular radiator loaded with split ring resonators (SRR) operates at the 0 mode and radiates an omnidirectional pattern, which realizes pattern diversity. By using surface-mounted varactors, the operating frequencies for the two radiation patterns can be tuned over a wide frequency range, from 1.7 GHz to 2.2 GHz, covering the 1.71-2.17 GHz LTE band, and a low mutual coupling between the two radiators is achieved. The antenna has also been prototyped. The measured results are in good agreement with the simulation results, verifying the proposed concept. The dual-mode MIMO system equipped with the proposed antenna elements is discussed within the context of a 3-D channel model, and it shows a superior array compactness and spectral efficiency (SE) performance compared to scenarios with single-mode elements.

Dual-band miniaturized composite right left handed transmission line ZOR antenna for microwave communication with machine learning approach

This article presents a dual-band miniaturized Composite Right-Left-Handed Transmission Line (CRLH-TL) in an open-ended terminal, employing the Machine Learning (ML) technique. The CRLH-TL antenna is designed on the FR4 epoxy substrate. The substrate size is 0.31λ0 × 0.09 λ0, where λ0 is the free space wavelength. The proposed antenna offers dual-band functionality with resonant frequencies at 2.49 GHz and 5.33 GHz. The measured dual-band impedance bandwidths are 14.46 % and 14.74 %, with gains of 0.85 dB and 1.67 dB, and radiation efficiencies of 91.78 % and 95.45 % obtained at resonating frequencies of 2.49 GHz and 5.33 GHz, respectively. The proposed antenna also offers bipolar-type radiation patterns in the E-plane, and omnidirectional radiation patterns in the H-plane, along with compactness and constant gain. Several ML methods, including Random Forest (RF), Decision Tree (DT), K-Nearest Neighbour (KNN), Extreme Gradient Boosting (XGB), and Artificial Neural Network (ANN), are used to optimize the antenna. Compared to other ML algorithms, RF ML techniques estimate reflection coefficient S11 with an accuracy of above 98 %. The proposed antenna is utilized in WLAN (5.15–5.35, 5.47–5.725 GHz) and Wi-MAX (5.2–5.8 GHz) microwave applications.

A PITD algorithm for analyzing composite right‐/left‐handed transmission line

AbstractIn this letter, a novel numerical algorithm is proposed for analyzing the composite right‐/left‐handed (CRLH) transmission line (TL). The proposed algorithm adopts the precise‐integration time‐domain technique to construct the update equation, overcomes the Courant–Friedrich–Levy (CFL) stability condition, and solves the CRLH TL equations in an explicit way. The implementation of the proposed algorithm is simple and straightforward. Numerical results validate that the proposed algorithm can solve CRLH TL equations correctly when large time steps are used, and improves computational efficiency compared with the conventional FDTD method.

A Singly Curved Conformal Phased Array with Integrated Particles-Based CRLH Phase Shifters

In this paper, a four unit cell micron-sized magnetic particles embedded composite right/left-handed (CRLH) transmission line metamaterial phase shifter is proposed. The variable phases are achieved by activating the micron-sized magnetic particles along the length of stub transmission lines of the CRLH transmission line structure. This causes to effectively change the inductance of stub transmission lines, which changes the phase of the RF signal. These structures can be activated in a symmetric or asymmetrical manner to obtain wide range of phase shifts. A prototype of cascaded four unit cell CRLH transmission line phase shifter with embedded silver-coated ferrites (magnetic particles) is designed, fabricated and tested for phase shifters applications. The measured phase response of the proposed phase shifter is in close agreement with the simulated phase response. Next, for the performance analysis of proposed phase shifter, a 1 × 4 conformal curved-shaped phased array operating at 5.8 GHz is fed with the four unit cell cascaded phase shifter in CST full-wave simulator. The conformal phased array with proposed integrated phase shifters was simulated for broadside pattern correction and main beam scanning at 20 degree on curved-shaped surface with different bend angles. The radiation pattern results obtained with the proposed integrated phase shifters are in close agreement with those obtained with direct excitation of the array.

Miniaturized Highly Selective Balanced Ultrawideband HTS Bandpass Filter Using CRLH Transmission Line Aided by Gray Wolf Algorithm

Miniaturized Highly Selective Balanced Ultrawideband HTS Bandpass Filter Using CRLH Transmission Line Aided by Gray Wolf Algorithm

CRLH‐TL‐loaded metamaterial antenna with frequency band and polarization reconfigurability

SummaryIn this communication, an asymmetric co‐planar waveguide (ACPW)–fed composite right–left‐handed transmission line (CRLH‐TL)–based frequency band and polarization reconfigurable antenna (RA) is presented. The reconfigurability is achieved by using a PIN diode. When the diode is in OFF state, meander line works as part of ground. Hence, the antenna is like a circular patch antenna working at 5.15 GHz. In the ON state, the antenna works as a CRLH‐TL‐based antenna with an additional lower band resonating at 2.45 GHz. The antenna also has circular polarization (CP) property. The lower 2.4 GHz band is covering for IEEE 802.11 b/g/n/ax/be applications, whereas the higher band is covering the WiFi bands of IEEE 802.11a/h/n/ac/ax/be applications with CP radiation (upper band). This antenna is effective in a scattering environment such as in urban areas and indoor communication.

A Voxel Vascular Structure-based Mannequin-like Arm Electromagnetic Model for Radio Frequency Biomedical Sensors.

Radio Frequency (RF) sensor is widely used to monitor physiological signals. Generally, RF sensor simulation is mostly done using a layered model, which sometimes cannot model the accurate properties in the real world. A voxel vascular structure-based mannequin-like arm electromagnetic model (VVS-MaM) is proposed to evaluate the RF sensor, which mainly gathers the real physiological signal. This model is built with high-precision Magnetic Resonance Imaging (MRI), and it can finish fast simulation while there is also a voxel-like part in it which means it has the advantages of both the layered model and the real human model. After modelling, both simulation and in-vivo experiments are designed to test this sensor. In the simulation, the simulated standard resonant frequency of the equivalent model is 1.8137 GHz, and the relative error of the VVS-MaM is 0.012 GHz, which is closer to the standard value than the layer model result of 0.049 GHz. Meanwhile, in the in-vivo experiments, an RF sensor based on a composite right/left-handed transmission line (CRLH-TL) and complementary split resonator rings (CSRRs) are fabricated, and the measurements from the real experiments are gathered and stored to compare with that of the simulation. The comparison shows that the relative error of the VVS-MaM (0.08804 GHz)is closer to the in-vivo measurements than that of the layer model (0.09891 GHz), which validates the performance of VVS-MaM.Clinical Relevance-Radio Frequency, magnetic resonance imaging, scattering parameter, composite right/left-handed, complementary split resonator ring.

A CRLH-TL Inspired Dual-Band Antenna With Polarization Diversity for Wrist-Worn Wireless Body Area Network Devices

A wrist-worn dual-band smartwatch antenna with polarization diversity is proposed for smartwatches. The antenna has a cylindrical structure with a diameter of 33.6 mm and a height of 6.8 mm. The radiated structure is inspired by composite right/left handed-transmission lines (CRLH-TLs) to realize a dual-band operation (2.4 GHz and 5.8 GHz WLAN band). The unit cell of the CRLH-TL is analyzed, and its equivalent circuit model and the dispersion curves are studied for mode analyzation. The +1 and -1 modes of CRLH TL are employed for dual-band operating, and two orthogonal-polarized modes are excited with different types of feeding structure to realize the polarization diversity with low coupling and low envelope correlation coefficients (ECC). The wrist model is built in both simulation and experiment to evaluate the performance of the antenna, which shows a good radiation and diversity performances. The measured degree of freedom (DoF) is 1.92 and the capacity is 17.39 bit/s/Hz with 30 dB SNR. The results of specific absorption rate (SAR) are also studied and they are pretty low. These characteristics of the proposed antenna make it a competitive candidate for wrist-worn wireless body area network devices.

Millimeter-wave low-loss on-chip metamaterial for 5G communication based on non-periodic composite right-/left-handed transmission line

This Letter reports a millimeter-wave low-loss on-chip metamaterial based on a concept of a non-periodic composite right-/left-handed (CRLH) transmission line (TL). Compared with a classic periodic unit cell, a non-periodic CRLH TL is proposed to obtain higher transmittance and better reflectivity. First, based on the CRLH TL theory, the LC values of the periodic transmission line were calculated. Second, Ti factors were derived using Chebyshev low-pass filter prototypes and the bandpass transformation theory. Third, these values were then used to calculate the factors of the non-periodic structure, which was eventually implemented using lumped elements. By analyzing the dispersion property, the proposed non-periodic CRLH metamaterial features both right-handed (forward wave) and left-handed (backward wave) propagating modes, which accounts for its wide bandwidth. For demonstration, a gallium arsenide-based integrated passive device process is adopted. As its main advantages, the fabricated metamaterial shows a high and flat transmission with minimum insertion loss of 0.68 dB at 30.2 GHz, and a low reflectivity better than −10 dB from 14 to 51 GHz of which the fraction bandwidth is over 120%.

A Phased Array Antenna with Novel Composite Right/Left-Handed (CRLH) Phase Shifters for Wi-Fi 6 Communication Systems

A linear phased array antenna excited with a novel composite right/left-handed (CRLH) phase shifters structure is proposed. The phase of the conventional CRLH transmission line is controlled with magnetically aligned micron-sized particles embedded inside the unit cell of the CRLH transmission line. The cascading of unit cells produces the desired phase shifts for the main beam scanning of the linear antenna array operating at a 5.5 GHz center frequency for Wi-Fi 6 applications. The proposed phase shifter design has a very low insertion loss (0.5–2 dB), excellent matching characteristics with the antenna array (less than −10 dB) and a small phase error (1–2 degrees). A 1 × 4 linear patch antenna phased array operating at a 5.5 GHz center frequency of the Wi-Fi 6 band is simulated using the Method of Moments (MoM) simulator platform. Then, the array is driven with the proposed novel CRLH phase shifters for the main beam at broadside and the main beam steered at 15- and 30-degree scan angles toward the desired users. For experimental validation, multiple unit cells of the proposed phase shifters are fabricated, and the 1 × 4 patch antenna array is fed with these fabricated unit cells of the phase shifters. The phased array radiation patterns are measured using an in-house fully calibrated anechoic chamber and were compared with simulated phased array patterns. The measured phased array patterns are in good agreement with the simulated patterns. As compared with commercially available phase shifters, the proposed novel CRLH phase shifters do not need external complex biasing circuitry, which is a major advantage in space constraint limitations at the router side of multi-user MIMO-OFDM systems.

Composite Right/Left-Handed Transmission Line Metamaterial-Inspired Small Antenna Design: Topologies, reconfigurability, and applications

With the development of modern wireless communication systems, the demand for high-performance, multifunctional, low-cost, and compact antennas has been increasing substantially. The greatest challenge when designing this type of antennas is the tradeoff between complexity and performance. More design freedom is therefore highly desired. As an important subtype of metamaterials, composite right/left-handed transmission line (CRLH-TL) metamaterials have paved the way to achieve this compromise. In this review article, first, the possible CRLH-TL topologies that can be used in antenna design are discussed, involving structures based on not only Cartesian but also polar coordinates and 2D CRLH-TLs. The reconfigurability of the CRLH-TLs in terms of operating mechanisms, reconfigurability methods, and control techniques is then reviewed. By applying these structures to electrically small antenna design, considerable extra design freedom can be obtained. In the literature, a whole range of novel antennas with remarkable performances have been reported, holding great potential for various applications, such as wireless body area networks (WBANs), multiple-input, multiple-output (MIMO), radio-frequency identification devices (RFIDs), wireless power harvesting, and so on. All of these applications are briefly discussed.

A Composite Right/Left-Handed Phase Shifter-Based Cylindrical Phased Array with Reinforced Particles Responsive to Magneto-Static Fields

A conformal cylindrical phased array antenna excited with composite right/left-handed (CRLH) phase shifters is proposed. The phase tuning of the CRLH phase shifter is achieved by embedding novel magneto-static field-responsive micron-sized particles in its structure. It is shown that through the tiny magnet activation of these novel magneto-static particles at appropriate locations along the length of CRLH stub and inter-digital fingers, variable phase shifts are obtained. The proposed particle-based CRLH phase shifter operates in C-band (5–6) GHz with a low insertion loss and phase error. The 1 × 4 cylindrical phased array is excited with the four unit cells of the proposed particle-embedded CRLH transmission line phase shifters to scan the main beam at desired scan angles. A prototype of a 1 × 4 cylindrical phased array excited with the particle-based CRLH phase shifters was fabricated, and the results show that the simulated results are in close agreement with the measured results. The conformal cylindrical array with the proposed particle-based CRLH phase shifters has great potential for use in printed and flexible electronics design where commercially available phase shifters have a definite drawback.

Low-profile high gain circularly polarized CRLH transmission line inspired antenna with artificial magnetic conductor for wearable applications

AbstractIn this work, a compact, wideband, circularly polarized wearable antenna is proposed using asymmetric coplanar strip feeding for wireless health monitor applications in the ISM frequency band. The proposed antenna consists of a composite right/left transmission line (CRLH TL) inspired structure to achieve compactness and a rectangular ring slot is created in the metallic ground to enhance the CP radiation of the antenna. A 5 × 5 artificial magnetic conductor unit cell-based metasurface is designed which is operating at 2.4 GHz as a ground plane for the CRLH-based CP antenna. Implementation of AMC-based metasurface as a ground plane results in enhancement of radiation characteristics of CRLH TL antenna. The proposed antenna has a small footprint of 50 × 50 mm2 with measured impedance bandwidth of 2.3–3.2 GHz. The 3 dB axial ratio bandwidth of the proposed antenna is 2.36–2.78 GHz with peak gain of 5.89 dBi. Simulation and experimental results show that proposed AMC-based antenna is robust in terms of structural deformation. Further, to validate the performance of the antenna for biomedical applications, we have simulated the proposed antenna with human phantom model. The proposed antenna exhibits stable scattering and radiation characteristics with the phantom body environment and due to the inclusion of AMC structure, the proposed design satisfies maximum specific absorption rate value given as per the IEEE standard safety guidelines.

A VHF Band Small CRLH Antenna Using Double-Sided Meander Lines

In this paper, a miniaturized very-high frequency (VHF) band antenna using both top and bottom meander lines is proposed. To design a compact size antenna in the VHF band, a Composite Right/Left-Handed (CRLH) transmission line is applied to antenna structure; additionally, both top and bottom meander lines were used to achieve a greater inductance. The CRLH transmission line unit cell operates at 88 MHz, and the fabricated antenna is designed by arranging 7-unit cells. The overall size of the proposed antenna is 0.087λ × 0.02λ × 0.0003λ at the lowest operating frequency, and the antenna operates at 84 MHz. The VSWR 3.5:1 reference operating bandwidth of the antenna is 2%. The received power of the proposed CRLH antenna was measured to verify the antenna performance.

A Wideband Antenna for GNSS Applications with Improved Orthogonal Dipole

This letter presents a wideband antenna for high-precision Global Navigation Satellite System (GNSS) applications. The antenna consists of a pair of improved orthogonal dipoles that are fed by a feed network with Composite Right/Left-Handed Transmission Lines (CRLH-TLs), a polygonal patch, and a reflector. By using improved orthogonal dipole, the beamwidth of the antenna is broadened. The CRLH-TLs is adopted in feed network to obtain outputs with stable phase difference. Experiment results indicate that the antenna has a less than 10-dB return-loss bandwidth in the range of 1.1 to 1.7 GHz, a 3-dB axial-ratio bandwidth from 1.2 to 1.6 GHz, and a larger than 6.37 dBi gain in the whole operating band. The measured results show that the proposed antenna has stable performance in the whole operating band, which means that it is a suitable antenna used for GNSS applications.

High-Sensitivity Grooved CSRR-Based Sensor for Liquid Chemical Characterization

In this work, a new complimentary split ring resonator (CSRR)-based sensor is proposed to sense chemical concentrations. A groove is created in the dielectric ring region of the CSRR to place the hollow tube containing the material under test (MUT). By placing the MUT in the region of high field concentration, higher sensitivity is achieved. The proposed novel and simple design alleviates the requirement of complex fluidic channels and space needed to place the MUT. The fabrication process is also simple with efficient utilization of the sensor’s sensitive region. The CSRR is excited uniquely through a transmission line with periodically placed capacitive gaps in series. By placing the capacitive gaps, effective negative permeability and permittivity are simultaneously achieved, and the structure exhibits metamaterial [composite right/left-handed transmission line (CRLH-TL)] left-handed behavior. Greater coupling of electromagnetic energy from the transmission line to the resonator is achieved by increasing the capacitive gap widths, which renders higher sensitivity. The main sensing parameter is the shift in the frequency of the transmission coefficient notch arising due to the placement of chemicals of varying concentrations throughout the ring region in the hollow tube. The sensor dimension is 4 cm (0.012 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda {g}$ </tex-math></inline-formula> ) <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times $ </tex-math></inline-formula> 4 cm (0.012 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda {g}$ </tex-math></inline-formula> ), with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda {g}$ </tex-math></inline-formula> being the guide wavelength. The large sensing bandwidth obtained is 1320 MHz that corresponds to high sensitivity of 14.66 MHz/unit change in concentration and 21.44 MHz/unit change in permittivity. The sensor is cheap and small, and the sensing process is simple offering instantaneous results.

Design of compact highly matched broadband balanced low‐noise amplifier at X‐band using CRLH transmission lines

This article presents broadband balanced low-noise amplifier (LNA) operating at X-band, which uses composite right/left-handed (CRLH) transmission lines as input–output matching networks. Proposed LNA eliminates lumped DC-blocking capacitors and is combined with a hybrid coupler to achieve better stability and matching. Presented CRLH matching technique enhances the matching quality, reduces the overall size and considerably improves the bandwidth and noise performance. The matrix analysis of the CRLH structure is provided to determine the exact dimension of microstrip lines for the highest stable gain and the lowest noise figure (NF). The LNA structure uses a HJFET technology as an active device, which is simulated using an ADS momentum and small-signal scattering parameters provided by the manufacturer. This LNA offers an improved impedance matching and measured the 20 dB S11 band-width of 16% (8.3–9.7GHz), which is in good agreement with simulation. Total area occupied by the fabricated LNA is only 1.7 λ 0 × 0.9 λ 0 @ 8.3GHz. The LNA also provides <1.8 dB NF based on the IEEE standard temperature (16.85 Celsius), and 1 dB gain flatness throughout the entire band along with a 1 dB compression point of −1 dBm and an output third point intercept point of 19.5 dBm. The proposed CRLH-based LNA can be a good candidate for compact receivers and sensors.