Composite Right/left-handed Transmission Line Research Articles

비-포스터 회로가 결합된 UHF 대역 CRLH 전송선 안테나 설계

In this paper, we propose an ultra high frequency(UHF) band military antenna using composite right/left handed(CRLH) transmission lines and non-Foster circuits. The antenna uses the zeroth-order characteristic of the CRLH transmission line in order to miniaturize the antenna. The non-Foster circuit’s negative capacitance can offset the input reactance of the antenna to improve bandwidth. The size of the CRLH transmission line antenna is 20.9×13.2×1.6 mm3 and the size of the non-Foster circuit is 20×14.4×1.6 mm3. The measured received power of the antenna is improved by an average of 19.96 dB at 250～500 MHz.

Beam‐scanning leaky‐wave antenna based on CRLH‐metamaterial for millimetre‐wave applications

This paper presents empirical results of an innovative beam-scanning leaky-wave antenna (LWA), which enables scanning over a wide angle from - 35° to + 34.5° between 57 and 62 GHz, with broadside radiation centred at 60 GHz. The proposed LWA design is based on composite right/left-handed transmission-line (CRLH-TL) concept. The single-layer antenna structure includes a matrix of 3 × 9 square slots that is printed on top of the dielectric substrate; and printed on the bottom ground-plane are Π- and T-shaped slots that enhance the impedance bandwidth and radiation properties of the antenna. The proposed antenna structure exhibits metamaterial property. The slot matrix provides beam scanning as a function of frequency. Physical and electrical size of the antenna is 18.7 × 6 × 1.6 mm 3 and 3.43λ 0 × 1.1λ 0 × 0.29λ 0 , respectively, where λ 0 is free space wavelength at 55 GHz. The antenna has a measured impedance bandwidth of 10 GHz (55-65 GHz) or fractional bandwidth of 16.7%. Its optimum gain and efficiency are 7.8 dBi and 84.2% at 62 GHz.

Matrix Power Amplifier With Open-Circuit Composite Right-/Left-Handed Transmission Line

A distributed matrix power amplifier with open-circuit (O.C) composite right-/left-handed (CRLH) transmission line (TL) is proposed. The matrix structure along with the zero phase-shift CRLH TL and the O.C termination of TLs have led to the design of reduced size, high-gain matrix amplifier with improved power performances. A new small size planar CRLH unit cell is presented. The maximum gain of 21.5 dB at the center frequency is obtained. The measured 1-dB gain compression (P1-dB) is 26 dBm, and the maximum power added efficiency is 29%. Better gain and P1-dB are achieved compared to the previously published narrowband distributed amplifiers. The amplifier has good linearity according to the measured input intercept point (18 dBm) and the output intercept point (39 dBm).

Design of CRLH Leaky-Wave Antenna With Low Sidelobe Level

Composite right/left-handed (CRLH) waveguide leaky-wave antenna (LWA) with low sidelobe level (SLL) and high radiation efficiency is investigated and designed in this paper. Due to the characteristic of negative and positive dominant mode propagation constant of the CRLH transmission line, a backward to forward beam-steering LWA can be realized through frequency scanning. The leaky-wave radiation is analyzed first based on a Ka-band CRLH waveguide with straight slots differently offset on the broadwall. The propagation constant maintains almost invariable as the slot offset varies, meanwhile the attenuation constant has a considerable dynamic range. Thus meandering long slot, whose offset varies along the CRLH waveguide, can be cut on the broadwall to generate a tapered excitation distribution. A prototype of the proposed CRLH waveguide LWA with meandering long slot is designed and fabricated to validate the design. Measurement results show that continuous beam-steering capability from −29° to +31° is achieved, meanwhile the optimized SLLs for the designed antenna patterns are kept below −18.5 dB in the major operating band with the minimum SLL of −22.4 dB at 33 GHz, and the average radiation efficiency is 65.4%. The realized SLLs and radiation efficiency performances of our CRLH LWA surpass others reported in open literatures.

Compact Frequency Reconfigurable Antennas Based on Composite Right/Left-Handed Transmission Line

The compact reconfigurable antennas based on composite right/left-handed (CRLH) transmission line are proposed and analyzed in this paper. The proposed antenna is fed by the asymmetric coplanar strip (ACPS) and consists of coupling radiation patch as well as a PIN diode. The differences of the antennas with meander line and without meander line are discussed. By utilizing a PIN diode as the CRLH transmission line termination, the termination states can be controlled, and the resonance of the antenna can thus be tuned between the two zeroth-order resonant frequencies. By switching the diode, the antenna with meander line is able to operate in single-band of 2.08-2.54 GHz and dual-bands of 1.65-1.84 GHz and 5.35-6.40 GHz, while the antenna without meander line is able to operation between two single-bands of 1.84-2.28 GHz and 4.6-6.0 GHz. All these operation bands cover the UMTS (1750 MHz-1780 MHz), ISM (2.4 GHz), WIMAX (2.5-2.69 GHz) and WLAN (2.4-2.484 GHz/5.725-5.825 GHz) applications. The radiation performance was simulated by High Frequency Structure Simulator, and the measurements were taken in an anechoic chamber to verify the simulation results. Good agreements are observed between the simulated and measured results. Moreover, the radiation patterns of the proposed antennas remain stable at different reconfigurable bands.

CRLH-Transmission Line for Design and Analysis of Compact Microstrip Patch Antenna

The composite right/left-hand transmission line is displayed as an ordinary Transmission Line having two type of properties, first one left-hand properties and second one right-hand properties. By demonstrating a metamaterial based CRLH as a comparing TL, TL hypothesis can be utilized for analysis and plan one-, two-, or even three-dimensional CRLH metamaterials. The structure of CRLH-TL has the arrangement of metamaterial transmission line (TL) made out clearly by composite right-/left-hand (CRLH) unit cells. The Composite Right Left Handed (CRLH) transmission lines are on recent displayed as a kind of artificial transmission lines with various microwave applications. This examination take a gander at various types of execution of these transmission lines and the impact over the execution. The examination is passed on utilizing both lumped parts and microstrip utilization of the unit cells. As a summed up, show for CRLH TL provides for an incredible level of excellent stage reaction, for instance, double band task, nonlinear frequency, bandwidth capacity upgrade, and furthermore the presence of basic frequency with zero phase velocity. In this paper, we discuss about a Microstrip Patch antenna which is based on composite right/left-hand transmission line.  Â

Fast method for analysing nonlinear composite right/left‐handed transmission lines based on finite‐difference time‐domain method

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.

High gain dual-band distributed amplifier using new composite right/left-handed transmission line

AbstractIn this paper, a high-gain dual-band distributed amplifier (DBDA) based on the metamaterial transmission line (TL) is proposed. To have two separate frequency bands in the distributed amplifiers, the composite right/left-handed (CRLH) TLs are used instead of conventional TLs. Although both forward and reverse gains of the distributed amplifiers are available in this case, they suffer from their low gains. In this paper, to increase the DBDA power gain, a new circuit architecture for the CRLH TL is introduced. By using the proposed CRLH TL, a lower wave attenuation coefficient at the forward band of the DBDA is achieved than the conventional structures, which causes a higher forward power gain. Simulation results also show that the power gain of the proposed DBDA is about 28.5 dB at the desired frequency bands, and good agreement between the measurement and simulation results confirms the accuracy of the design method.

Novel compact CRLH‐TL‐based tri‐band MIMO antenna element for the 5G mobile handsets

AbstractA novel compact tri‐band multiple‐input multiple‐output (MIMO) antenna element based on composite right/left‐handed transmission line (CRLH‐TL) for the fifth‐generation (5G) mobile handsets is presented. First, by using the coupled‐fed loop with the CRLH‐TL zeroth‐order resonator (ZOR) structure, we propose a compact antenna element covering 1.525/3.45/4.9 GHz bands (1490‐1560/3300‐3600/ 4800‐5000 MHz). A band‐stop matching circuit (BSMC) is also added between the feeding point and the element to expand the 1.525 GHz band to 1490‐1710 MHz. Then, an MIMO array with eight proposed tri‐band elements is designed and fabricated. The measured results show that the MIMO array operates in 1.6/3.45/4.9 GHz bands (1490‐1710/3300‐3600/4800‐5000 MHz) with good isolations (more than 10 dB) and acceptable radiation efficiencies. Furthermore, the envelop correlation coefficients (ECCs) between any two elements in the MIMO array are less than 0.23.

A Novel Metamaterial Transmission Line With Adjustable Left-Handed Elements and Its Application to <inline-formula> <tex-math notation="LaTeX">$H$ </tex-math> </inline-formula>-Plane Filter

This letter presents a metamaterial transmission line (TL) with enhanced designing flexibility. Interdigital fingers and rectangular slots are etched on the top and bottom metal plates to generate series capacitances and shunt inductances, respectively, which give rise to the composite right-/left-handed (CRLH) property. In this structure, the rectangular slots provide adjustable shunt inductances that facilitate the design of CRLH property compared with that in previous work. Furthermore, the increment of the shunt inductances also enables more compact size due to lower resonance. Examples are given to verify the advantages by comparing the dispersions, S-parameters, and extracted values of lumped elements for two types of CRLH TLs with various physical dimensions. In addition, a bandpass filter is implemented by the proposed CRLH TL with partial H-plane coupling structure. The filter is fabricated and measured, and the result shows a good agreement between the measurement and simulation.

Miniaturized Active Metamaterial Resonant Antenna With Improved Radiation Performance Based on Negative-Resistance-Enhanced CRLH Transmission Lines

In this letter, a miniaturized microstrip resonant antenna (MRA) based on the active metamaterial resonator is presented. Unlike the passive composite right/left-handed (CRLH) resonators, the presented active metamaterial resonators are realized using the negative-resistance-enhanced CRLH transmission line that incorporates active circuits for loss compensation. The active circuit uses bipolar junction transfer in its inverted-common-collector configuration to provide a negative resistance for the proposed active MRA. The presented passive and active antennas both operate in the negative-first-order resonance mode and thus have reduced dimensions compared to the conventional planar MRAs. The integration of the active elements delivers higher radiation gain compared to the passive negative-order CRLH resonator antenna. The passive and active antennas were fabricated, and the measured results are presented to validate the concept.

Wider frequency domain for negative refraction index in a quantized composite right–left handed transmission line**Project supported by the National Natural Science Foundation of China (Grant Nos. 61205205 and 6156508508), the General Program of Yunnan Provincial Applied Basic Research Project, China (Grant No. 2016FB009), and the Foundation for Personnel Training Projects of Yunnan Province, China (Grant No. KKSY201207068).

The refraction index of the quantized lossy composite right-left handed transmission line (CRLH-TL) is deduced in the thermal coherence state. The results show that the negative refraction index (herein the left-handedness) can be implemented by the electric circuit dissipative factors(i.e., the resistances R and conductances G) in a higher frequency band (1.446 GHz≤ ω ≤ 15 GHz), and flexibly adjusted by the left-handed circuit components (Cl, Ll) and the right-handed circuit components (Cr, Lr) at a lower frequency (ω = 0.995 GHz). The flexible adjustment for left-handedness in a wider bandwidth will be significant for the microscale circuit design of the CRLH-TL and may make the theoretical preparation for its compact applications.

Analogue predistorter based on non‐linear CRLHTL

A low insertion loss (IL) analogue predistorter using non-linear composite right–left-handed transmission line (CRLHTL) is presented. The proposed predistorter consists of two symmetrical CRLHTL unit cells. In the experiment, this predistorter can achieve about 2.2 dB gain expansion and 17° phase shift during 4.4–4.5 GHz with only 4.3 dB IL. A C-band 40 W solid-state power amplifier observes 8.1 dB enhancement in the intermodulation at −6 dB output power backoff when linearised by the proposed predistorter.

Compact planar multiband MIMO antenna based on composite right/left‐handed transmission line for mobile phone applications

AbstractA novel compact planar multiband multiple‐input multiple‐out (MIMO) antenna based on composite right/left handed transmission line (CRLH‐TL) for mobile phone applications is presented in this article. The proposed MIMO antenna consists of two asymmetric antenna elements and two‐sided shorted ground, which is designed by zeroth‐order resonant theory to achieve compact performance. The proposed antenna elements cover the communication bands in 698–960 MHz and 1710–2690 MHz with the planar size of 16 × 56 mm2 and 12 × 56 mm2, respectively. Acceptable agreement between simulated and experimental results over the desired operating bands is observed. The envelop correlation coefficients are calculated by the S parameters.

Extended Aperture Miniature Antenna Based on CRLH Metamaterials for Wireless Communication Systems Operating Over UHF to C‐Band

AbstractThis paper presents a simple technique to extend the aperture of planar composite right/left‐handed (CRLH) metamaterial antennas with minimal impact on the antenna's dimensions. Unlike most CRLH antenna structures the proposed antenna is via‐free. The proposed antenna is shown to operate over a wideband from UHF to C‐band with good radiation characteristics. The antenna configuration consists of a vertically stacked CRLH unit cells comprising a patch and meandered lines, where the patch is engraved with an S‐shaped slot. The design uses minimal ground plane area. The meander line inductance is grounded using coplanar waveguide (CPW) ground which eliminates conventional CRLH transmission line metallic via into ground plane. The antenna is feed through a coplanar waveguide (CPW) match stub that is electromagnetically coupled to the unit cells. Antenna dimensions are 17.5 × 32.15 × 1.6 mm3, which corresponds to 0.204 λ0 × 0.375 λ0 × 0.018 λ0 where free‐space wavelength (λ0) is 3.5 GHz. Parametric study enabled the optimization of the antenna performance in terms of impedance bandwidth, radiation gain, and radiation efficiency. Measured results confirm that the antenna can operate from 850 MHz to 7.90 GHz, which is equivalent to a fractional bandwidth of 161.14%. The antenna has a maximum gain and radiation efficiency of 5.12 dBi and ~80%, respectively, at 3.5 GHz.

A compact and high performance dual-band bandpass filter based on unbalanced composite right/left-handed transmission lines for WLANs applications

In this paper, a novel compact microstrip dual-band (DB) bandpass filter with high selectivity for wireless local area networks applications is proposed. The design procedure is based on unbalanced composite right/left-handed (UCRLH) transmission lines (TLs). The DB features can be achieved by unbalancing the CRLH transmission line. The necessary conditions to obtain a discontinuous transition between the left- and right-handed bands, intended to provide UCRLLH TL, are investigated. The application of this technique to design of compact DB filters is illustrated. The structure of the proposed DB filter is implemented by a series interdigital capacitor located between two microstrip lines that shorted to the ground plane by vias. The vias with microstrip lines acting as a shunt connected inductor while the series capacitor is realized by interdigital capacitor. The design procedure based on a simple equivalent circuit is also introduced. The proposed filter has advantages such as compact size, easy fabrication, high selectivity, low insertion loss, high return loss and, design flexibility. To validate the proposed technique, the proposed DB filter has been fabricated and tested. Good agreement has been found between simulation and measurement results. The total size of the proposed UCRLH DB filter is 0.17 λg × 0.048 λg, where λg is the guided wavelength of the lower pass-band. The size of the proposed DB filter is more compact in comparison with known similar filters.

Coaxially Fed Monopole Antenna With Choke Structure Using Left-Handed Transmission Line

A composite right/left-handed (CRLH) transmission line (TL) is proposed for a choke structure. The dispersion relation of the CRLH TL is designed with the left-handed (LH) branch at around 700 MHz. The proposed CRLH TL is applied to the choke structure. The radiation patterns and current distributions on the outer conductor of the coaxial cable are calculated to verify the operation of the choke structure. The characteristics of a conventional sleeve antenna are calculated and compared with those of the proposed antenna. To verify the simulation results, the proposed antenna is fabricated. The $|S_{11}|$ characteristics, the radiation patterns, and the total antenna efficiency are measured. At 585 MHz, the length of the monopole and the choke structure using LH TL are 0.12 and 0.05 wavelength, respectively.

A CRLH leaky wave antenna on SIW with continuous scan using novel S-slots

ABSTRACTThis article realises a leaky wave antenna based on composite right left-handed (CRLH) transmission line (TL) with novel S-shaped slots on substrate integrated waveguide (SIW). For realising CRLH TL and for providing series capacitance, the slots are etched in the top layer of SIW. The proposed unit cell is repeated in one dimension to get an array, showing continuous beam scanning in a wide range of 74° for fractional bandwidth of 43%, beam scanning starts from −49° to 25° for the frequency scan of 30–42.8 GHz. Simulated results shows almost constant and high gain values of ~15 dBi (max) in the specified scan range, with more than 75% radiation efficiency. The proposed antenna is very small, compact and is having dimensions of 48.7 × 7.6 mm2. A prototype of the proposed antenna is fabricated and tested for verification, a good agreement between simulated and measured S parameters has been observed.

Design of a Dual-Band Class-AB/-J Power Amplifier with CRLH Transmission Line and Nonlinear GaN Transistor Model Simulation

Design of a Dual-Band Class-AB/-J Power Amplifier with CRLH Transmission Line and Nonlinear GaN Transistor Model Simulation

The thermal effect on the left-handedness of the mesoscopic composite right-Left handed transmission line

Starting from the quantum fluctuation of current in the mesoscopic composite right-left handed transmission line (CRLH-TL) in the thermal Fock state, we investigate the left-handedness dependent of the frequencies, intensity and quantum fluctuations of the current field in the CRLH-TL under different thermal environment. The results show that the intensity and quantum fluctuations of current field in lower frequency bands affect the left-handedness distinctly under different thermal environment. The thermal effect on the left-handedness in the mesoscopic CRLH-TL deserves further experimental investigation in its miniaturization application.