CRLH TL Research Articles

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.

A Design of Metamaterial Inspired Resonator for Multifrequency Fluidic Sensors

This letter presents a multifrequency planar resonator fed by coplanar waveguide (CPW) for the determination of dispersive fluidic materials. By employing composite right-/left-handed transmission line (CRLH TL) in the resonator, the characteristic of multiresonance has been achieved in a compact size (0.17 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times \,\,0.15\lambda _{0}^{2}$ </tex-math></inline-formula> ), which can enhance the sensitivity of the resonator as a sensor at multiple frequencies. The substrate is integrated with a fluidic container made of polydimethylsiloxane (PDMS). The optimum design operates at 2.28, 2.95, and 10.6 GHz to cover both the lower and the higher frequency bands. Also, it shows very good sensitivity (0.98, 0.7, and 0.67) at each resonant frequency. Deionized water at different temperatures and water–ethanol mixtures are used to verify the performance of the sensor in multiple frequency bands. The advantages of the proposed design, including compact size, multifrequency resonances, and high sensitivity, make it a competitive solution for detecting biological samples with similar electromagnetic properties in a single-frequency band.

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.

Class-E Power Amplifier with Improved PAE Bandwidth Using Double CRLH TL Stub for Harmonic Tuning

Class-E Power Amplifier with Improved PAE Bandwidth Using Double CRLH TL Stub for Harmonic Tuning

A Sensitivity-Enhanced Sensor Based on Zeroth-Order Resonance for Liquid Characterization

A high-sensitivity planar microfluidic sensor is proposed in this paper based on composite left/right-handed transmission line (CRLH TL). By employing the series zeroth-order resonance (ZOR), the resonance of proposed sensor is only determined by surface capacitance and inductance. The short-circuit structure reduces the energy loss due to edge radiation and generates a highly concentrated electric field on the top surface of the substrate, which can be used to detect the dielectric loading samples. The presented sensor has been simulated, fabricated and tested. The sensor on the printed circuit board (PCB) is integrated with the fluidic container made of polydimethylsiloxane (PDMS) to form the test device. The water-ethanol binary mixture and sucrose solution are used to proof the concept. Finally, the prediction model for the water-ethanol mixture based on measured parameters has been established and the analysis of prediction error has been carried out. The sensor works around 4 GHz, and the maximum sensitivity reaches 1.04. Due to the high sensitivity and simple structure, the proposed structure is a competitive candidate for the applications including bio-sensing and portable biomedical device.

Zig-Zag Monofilar Spiral Shaped CRLH TL Based Compact Lowpass mono-/duo-/tri-/quad-bandpass Filter

ABSTRACT Planar compact lowpass mono-/duo-/tri-/quad-bandpass filters design based on CRLH TL are presented. Filters are designed by cascading two unit-cells composed of Zig-Zag monofilar spiral lines (ZZMSL) and Zig-Zag open ring (ZZOR) loaded on the main transmission line. Only the length of ZZMSL which is housed within the fixed length of ZZOR is utilized to generate the multiple passbands, so all of the filters are of the same size. At the lowpass (LP) band of the filter’s −3 dB cut-off frequency of 0.71 GHz, the filter’s footprint area (excluding the feed line), is 0.083 λg × 0.034 λ g . The LP band's measured −3 dB cut-off frequency is 0.71 GHz, with a minimal in-band insertion loss of 0.22 dB and a return loss better than 20 dB from DC to 0.46 GHz. The measured center frequencies for four bandpass passbands are 1.3, 2.08, 3.37, and 4.6 GHz, with a −3 dB FBW of 76.15%, 10.57%, 8.6%, and 7.8%, respectively. The minimal insertion losses within the BPs are 0.26, 0.26, 0.39, and 0.4 dB, respectively, whereas the return losses are 33, 36, 19, and 37 dB. Lower in-band insertion loss, good band-to-band isolation, the controllable center frequency with good out-of-band skirts, higher compactness, and lower circuit complexity are all advantages of the proposed lowpass quad-bandpass filter. The Lowpass quad-bandpass filter is finally manufactured. A good agreement between electromagnetic simulation, circuit model simulation, and experimental measurement results validates the design process and filter performance.

A Broadband Antenna Based on a Single CRLH TL Unit Cell and a Parasitic Strip for Sub-1GHz DVB and LTE Applications

A Broadband and slim profile antenna based-on a single composite right/left-handed transmission line unit cell and parasitic shorted strip is presented for sub-1 GHz digital video broadcasting and long-term evolution applications (470-970 MHz). It is comprised of an ungrounded coplanar waveguide that feeds a meandered strip (distributed series inductors), which is connected through capacitive coupling (series capacitance) with a virtual small ground, while an upper shorted meandered strip represents a parallel inductor. A shorted meandered strip (parasitic inductor) is added to create a third resonant frequency. A broadband operation is achieved by merging three different resonant modes frequencies (zeroth-order mode and two quarter wavelength monopole modes) to satisfy 6 dB bandwidth criterion. A prototype is constructed and measured in order to verify the achieved results. The results of reflection parameter, gain, efficiency, patterns and bandwidth efficiency product are presented, discussed, and evaluated with respect to literature. The results show that the proposed antenna is a potential candidate for recent broadband digital video broadcasting applications.

A Novel Design Approach for Compact Wearable Antennas Based on Metasurfaces.

This paper presents a novel approach to design compact wearable antennas based on metasurfaces. The behavior of compact metasurfaces is modeled with a composite right-left handed transmission line (CRLH TL). By controlling the dispersion curve, the resonant modes of the compact metasurface can be tuned efficiently. A printed coplanar waveguide (CPW) monopole antenna is used as the feed structure to excite the compact metasurface, which will result in a low profile antenna with low backward radiation. Following this approach, two compact antennas are designed for wearable applications. The first antenna is designed to operate at its first negative mode (-1 mode), which can realize miniaturization, but maintain the broadside radiation as for a normal microstrip antenna. The proposed prototype resonates around 2.65GHz, with a matching bandwidth of 300 MHz. The total dimensions of the antenna are 39.4×33.4 mm2 (0.1 λ02), and its maximum gain is 2.99 dBi. The second antenna targets dual-band operation at 2.45 and 3.65 GHz. A pair of symmetric modes (±1 modes) are used to generate similar radiation patterns in these two bands. The size of the antenna is 55.79×52.25 mm2 (0.2 λ02), and the maximum gains are 4.25 and 7.35 dBi in the two bands, respectively. Furthermore, the performance of the antennas is analyzed on the human body. The results show that the proposed antennas are promising candidates for Wireless Body Area Networks (WBAN).

A Wide-Angle Scanning Leaky-Wave Antenna Based on a Composite Right/Left-Handed Transmission Line

This paper presents a frequency-independent, wide-angle scanning leaky-wave antenna (LWA), based on the composite right/left-handed transmission line (CRLH TL). The proposed LWA consists of a coplanar waveguide-grounded (CPWG) structure loaded by varactors. Loaded varactors are used to control the phase constant of the fundamental mode of the LWA by adjusting the applied DC voltage. The LWA has an excellent wide-angle scanning capability, a simple structure, and low cost. Results show that the main beam of an LWA with 20unit cells can scan from −66° to 62° at the operation frequency of3.0 GHz, with a peak gain of 9.9 dBi, and a gain fluctuation of less than 4.9 dB. The operation bandwidth and radiation efficiency are about 13% and over 50%, respectively. A 10-unit cascaded LWA prototype was designed, fabricated, and measured to verify the design concept.

Wideband directive emission based on hyperbolic metamaterials

Wideband directive emission properties operating in the canalization regime are found in hyperbolic metamaterials (HMMs). Based on the two-dimensional composite right/left-handed transmission line (CRLH TL) with lumped elements, the proposed HMM exhibits a very flat wave vector iso-frequency dispersion diagram over a wide frequency range. The emitted electromagnetic energy is concentrated around the normal of the HMM slab for all incident angles, and a subwavelength focusing is thus achieved. Canalization-induced abnormal propagations including wideband highly directive emission and subwavelength focusing are verified experimentally in the microwave domain.

A compact planar diplexer based on via-free CRLH TL for WiMAX and WLAN applications

AbstractIn this paper, design and development of a via-free composite right/left handed transmission line (CRLH TL)-based diplexer for WiMAX and WLAN bands is reported. The diplexer is having two channels, where each channel consists of a separate bandpass filter (BPF). The BPF of both channels are designed on via-free CRLH TLs based on a newly proposed right-angled corner-modified split ring resonator (RAC-MSRR) structure. The RAC-MSRR incorporates meander paths because of which working scope of frequencies is focused for measured center frequencies (f1) 3.5 GHz with −3 dB fractional bandwidth (FBW) of 21.21% (BPF1 channel) and (f2) 5.6 GHz with −3 dB FBW of 13.29% (BPF2 channel). For diplexer design, T-section is used for joining two BPFs which results in very good isolation of more than 32.5 dB over the frequency band of 2.5–8.0 GHz. The designed diplexer has passband insertion loss of −0.87 dB at f1 and −1.25 dB at f2. Overall size of the fabricated diplexer including 50 Ω feed line is 18 × 15 mm2. Equivalent lumped circuit model parameters of the diplexer are obtained from the pseudo-inverse matrix technique. Measured results show good concurrence with simulated results and subsequently approve the proposed model design.

Compact QMSIW bandpass filter using composite right/left‐handed transmission line in grounded coplanar waveguide

A novel compact quarter-mode substrate integrated waveguide (QMSIW) bandpass filter based on composite right/left-handed transmission line (CRLH TL) in grounded coplanar waveguide (GCPW) is proposed in this work. Two unit cells CRLH TL is implemented at the inductive window of two coupled QMSIW resonators, does not occupy any extra area and minimizes size of the proposed filter. The characteristics of the CRLH unit cell are analyzed in order to get one transmission zero (TZ) at the lower stop band and one pole at the center frequency of the filter. Therefore two unit cells CRLH TL gives two poles at the center frequency and one TZ at the lower stop band of the filter. In addition to this, the proposed structure of the filter gives two more TZs at upper stop band to obtain better selectivity and wide stop band performance. To validate the proposed method, a fourth-order bandpass filter (BPF) is designed and fabricated on a single layer Rogers RO3003 substrate. The measured results are 14% fractional bandwidth (FBW) with 8.4 GHz center frequency, a return loss (RL) better than −18 dB, and an insertion loss (IL) less than −1.55 dB. Three TZs are obtained at 7.42, 9.97, and 13.42 GHz with rejection levels of −31.51, −28.43, and −53.56 dB, respectively. The simulation result shows a good match with measured S-parameters.

Wave propagation of the perturbed nonlinear Schrödingers equation in the nonlinear left-handed transmission lines

This paper secures chirped dark and bright solitons of the perturbed nonlinear Schrödinger equation with parabolic law nonlinearity and self-steepening effect in the nonlinear left-handed metamaterials (NLHMs). We use the ansatz method, sine-cosine, csch function method and the auxiliary equation method to fall out the various soliton solutions. In view of the results obtained, rational, hyperbolic and trigonometric solutions emerge and there are new in CRLH TL. The existence criteria of these solutions are also discussed. Finally, we observed that the use of the auxiliary equation method leads to the abundant and efficient solutions than the other methods.

28 GHz Microstrip Patch Antennas for Future 5G

Recently, the industry and academia there is significant activity in research and development towards the next generation micro and Pico cellular wireless Networks (5th generation). This paper presents, a structure design of microstrip patch antenna array operate at the central frequency of 28 GHz waveband is proposed. The patch antenna array consists of four elements with rectangular patch and uniform distribution. It has a compact size of 26.51 x 20.37 mm with operating frequency at 28 GHz. The inset feed technique is used for the matching between radiating patch and the 50Ω microstrip feedline. The proposed 2x2 antenna array successfully improve the antenna gain up to 8.393dB compare to existing CRLH TL CPW antenna with 2.99 dB, wideband antenna with 7.1 dB and 3.7 dB for broadband elliptical-shaped slot antenna. As a conclusion, the directivity of 10.13 db and efficiency is higher than 80% considered as a potential candidate for the 5G wireless networks and applications.

Novel dual band patch antenna With Gap coupled composite right/left-handed transmission line

AbstractA novel low profile dual band patch antenna is presented. It consists of a composite right/left-handed transmission line (CRLH TL) unit cell gap coupled with the radiating edge of a rectangular patch antenna. The dual band behavior is achieved by coupling the zeroth order resonance mode of CRLH TL and TM10 mode of the patch antenna. It is shown that frequency ratio can be changed by varying the gap between the patch and CRLH TL unit cell. The proposed configuration enables frequency reconfigurability by changing the CRLH TL unit cell using a switch. A prototype of the antenna having frequency ratio f2/f1 = 1.08 is designed and fabricated. The proposed antenna shows measured S11 ≤ −10 dB bandwidth of 100 and 50 MHz at resonance frequencies of f1 = 4.84 and f2 = 5.22 GHz, respectively. A 2 × 2 dual band CRLH TL coupled patch array is also presented, showing more than 12.7 dBi gain at both resonance frequencies.

Novel Two-Dimensional CRLH TL and its Application on Tri-Band Omnidirectional Antenna

Abstract A new type of two-dimensional composite right/left handed transmission line (2D CRLH TL) is proposed in this letter. Utilizing this structure, an antenna operating on GLONASS and WLAN based on dual zeroth-order resonance (ZOR) mode and first-order resonance (FOR) mode is designed and fabricated. By taking advantage of coaxially center feed and symmetric structure, nearly all omnidirectional radiations in XOY plane at three operating frequencies is obtained. Furthermore, the antenna gain has a high value of −1.27 dB in f1=1.60 GHz, −3.89 dB in f2=2.39 GHz and 0.67 dB in f3=5.12 GHz respectively.

Design of a Compact UWB Bandpass Filter using Via-Less CRLH TL

A novel compact ultra wideband (UWB) bandpass filter (BPF) based on composite right/left handed transmission line (CRLH TL) is reported in this paper. The proposed UWB BPF is designed and developed by coupling of two unit-cells of via-less CRLH TL, excited by asymmetrical coplanar waveguide (CPW) feed-line. The unit cell of CRLH TL is designed using series interdigital capacitor (IDC) in shunt with the shorted inductive stub. Because of the CPW-fed, no via is required to get the shunt inductance for the realization of CRLH TL, which minimizes the fabrication steps. The filter is compact in size 11.9 x 6 mm 2 . The proposed filter exhibits the return-loss (|S 11 |) more than 11.2 dB and insertion-loss (|S 21 |) less than 0.5 dB and low and flat group delay response throughout the passband, 3.3 GHz to 13.0 GHz. The proposed UWB BPF also shows the good stopband rejection (|S 21 | > 20 dB and |S 11 | < 0.8 dB) from 13.6 GHz to 15 GHz and steep roll-off from passband to stopband. The fractional bandwidth (FBW) of the filter is found to be 119 %. The equivalent lumped circuit model of the filter is obtained through Ansoft Designer. All simulated results are extracted through method of moment based simulator, IE3D. Agilent vector network analyzer (VNA) is used to get the measured results. All measured results are found in close similarity with the simulated results.

Design and Analysis of a New ZOR Antenna with Wide Half Power Beam Width (HPBW) Characteristic

Abstract Novel zeroth-order resonator (ZOR) composites epsilon-zero resonance (EZR) and mu-zero resonance (MZR) characteristics was proposed. The proposed resonator was constructed by moving via from centre of the conventional mushroom structure (CMS) to the edge, then, an edge-located via mushroom structure (ELV-MS) was formed. Thus, boundary conditions were transformed from all open-ended to half short-ended and half open-ended. Then, the new ZOR composites EZR and MZR characteristics (called EZR-MZR resonator). Owing to the unique characteristic of the composite EZR and MZR, the proposed ZOR antenna radiates both horizontal-polarized field (uni-directional) and vertical-polarized field (omni-directional). Then, wide half power beam width (HPBW) radiation patterns were realized for the antenna. The deduction and analysis of the proposed EZR-MZR resonator were conducted based on the composite right/left-handed transmission line (CRLH TL) and ZOR theories, and field distributions. The proposed ZOR antenna was investigated with two cases of coupling feeding.

A miniaturized UWB via‐less CRLH‐TL loaded CPW FED patch antenna

ABSTRACTA novel miniaturized ultra‐wide band (UWB) via–less composite right hand left hand transmission line (VL‐CRLH TL) loaded‐coplanar waveguide (CPW) fed monopole antenna has been designed. The CRLH unit cell has been realized with series capacitance and parallel inductance and implemented with gap capacitance and meander line inductance respectively. The meander line inductance is grounded using CPW ground through rectangular stub which eliminates conventional CRLH TL metallic via into ground plane. The proposed antenna is constructed of two unit cells fed by a CPW feed. The offset of feed location attached to patch is more important for impedance matching between them and proposed optimum feed location offset lof = 0.6 mm, which eliminates additional quarter wave transformer to impedance match. The total compact antenna dimension is 25 × 15 × 1.6 mm3 or 0.12λ0 × 0.07λ0 × 0.008λ0, where λ0 is free‐space wavelength at 1.55 GHz. It covers the impedance bandwidth (S11&lt; −10dB) of 1.55 GHz – 14.25 GHz, which corresponds to 160% of fractional bandwidth. The minimum and maximum gain of antenna are 1 dBi at 1.55 GHz and 3.5 dBi at 8.4 GHz respectively, which is suitable for UWB applications. The parametric study of antenna has been done using CST microwave studio and a prototype of the antenna with FR4 substrate is fabricated and tested. Good agreement between simulated and measured results. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:2485–2492, 2016

Wideband leaky-wave antenna with consistent gain and wide beam scanning angle based on multilayered substrate integrated waveguide composite right/left-handed transmission line

In this article, a wideband leaky-wave antenna is designed for consistent gain and wide beam scanning angle by using the proposed multilayered substrate integrated waveguide (SIW) composite right/left-handed transmission line (CRLH TL). The proposed SIW CRLH structure consists of two parts: an interdigital fingers slot of rotating 45° etched on the upper ground of the SIW, and a rotated parasitic patch beneath the slot. Due to the continuous phase constants change from negative to positive values of the proposed SIW-CRLH under the balanced condition, the designed LWA can achieves a continuous beam-scanning property from backward to forward over the operating frequency band. The designed antenna is fabricated and measured, the measured and simulated results are in good agreements with each other, indicating that the designed antenna obtains a measured continuous main beam scanning from backward −78° to forward +76° over the frequency range from 7.7 to 12.8 GHz with a consistent gain of more than 9.5 dB. Besides, the designed antenna also exhibits a measured 3-dB gain bandwidth of 45.1% with maximum gain of 15 dB. © 2016 Wiley Periodicals, Inc. Int J RF and Microwave CAE 26:731–738, 2016.