Composite Right/left-handed Antenna Research Articles

MmWave Zero Order Resonant Antenna with Patch-Like Radiation Fed by a Butler Matrix for Passive Beamforming.

A small zero-order resonant antenna based on the composite right-left-handed (CRLH) principle is designed and fabricated without metallic vias at 30 GHz to have patch-like radiation. The mirror images of two CRLH structures are connected to design the antenna without via holes. The equivalent circuit, parameter extraction, and dispersion diagram are studied to analyze the characteristics of the CRLH antenna. The antenna was fabricated and experimentally verified. The measured realized gain of the antenna is 5.35 dBi at 30 GHz. The designed antenna is free of spurious resonance over a band width of 10 GHz. A passive beamforming array is designed using the proposed CRLH antenna and the Butler matrix. A substrate integrated waveguide is used to implement the Butler matrix. The CRLH antennas are connected to four outputs of a 4×4 Butler matrix. The scanning angles are 12∘, -68∘, 64∘, and -11∘ for excitations from port 1 to port 4 of the 4×4 Butler matrix feeding the CRLH antenna.

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 Design of Compact Meta-material CRLH Antenna for Wireless Applications

This article presents a compact design of a composite-right-left-handed (CRLH) antenna for wireless applications. The antenna is fed using a coplanar waveguide (CPW) feed structure. The CRLH-antenna is comprised of one CRLH unit cell. The CRLH unit cell has a series capacitance (interdigital capacitor) and a shunt inductor (stub meander inductor). The antenna achieves compactness with a small size of 16.5 mm × 26 mm × 1.6 mm, thanks to the CRLH features such as nonlinear phase. The proposed antenna achieves a size reduction of better than 50 % with respect to the microstrip patch antenna operated at the same frequency band. The operating frequency band of the proposed antenna is from 5.83GHz to 6.3 GHz for WLAN applications, dedicated short range communications (DSRC), and intelligent transportation systems (ITS). Also, the antenna fulfills a radiation performance of omnidirectional pattern. To confirm the antenna design performances, a prototype is fabricated, and the reflection coefficient and radiation patterns are measured. Furthermore, the measured results have a good match with the simulation results.

Composite right/left‐handed ultra‐wideband metamaterial antenna with improved gain

AbstractA coplanar waveguide‐fed ultra‐wideband (UWB) composite right/left‐handed (CRLH) antenna is presented. It is designed by embedding CRLH unit‐cell on the top side and split‐ring resonator (SRR) on the bottom side of FR4 epoxy substrate. The UWB response is obtained by merging the resonances of CRLH unit‐cell and SRR with two additional resonances due to patch feed‐line and ground plane, respectively. Subsequently, the gain of UWB CRLH antenna is enhanced by loading two partial reactive impedance surfaces (PRISs) on the double layer FR4 substrate. First PRIS is embedded directly on the rear side of CRLH antenna (upper layer substrate) whereas the second PRIS is designed on the backside of the lower layer substrate. A considerable improvement in gain is observed over the frequency range from 6.2 to 10.6 GHz with peak enhancement of 1.75 dB. The proposed antenna is fabricated and measured. The measured results indicate −10 dB fractional bandwidth of 126.15% (3‐13.25 GHz) with realized gains of 2.2, 5.25, 5.5, and 7.3 dBi at 3.57, 7.46, 8.92, and 10.59 GHz, respectively. The simulated radiation efficiency is above 61% with a peak value of 86.21%. All measured and simulated results match reasonably well.

A Compact Highly Efficient Π-Section CRLH Antenna Loaded With Textile AMC for Wireless Body Area Network Applications

An ultrathin, compact, and highly efficient antenna based on the π-section composite right/left-handed (CRLH) methodology is presented. It operates at 2.45 GHz of the Industrial, Scientific and Medical (ISM) band with a physical size of 25 mm × 25 mm, a realized gain of 2.34 dBi, and a total efficiency of 87% in free space. Nevertheless, to maintain resonance at 2.45 GHz with body-loading scenarios, a high separation was required, leading to an overall large size. To circumvent that, an all-textile 2 × 2 artificial magnetic conductor (AMC) array was placed in-between the antenna and the human body. In free space, the low-profile integrated design exhibited a gain of 7.63 dBi (enhancement of 5.29 dBi) and total efficiency of 96.4%. The integrated design achieved a gain and total efficiency enhancements by 14.88 dBi and 72.4%, respectively, as well as, lower specific absorption rate (SAR) levels, in comparison with the CRLH antenna alone, for human loading cases. Results are achieved through circuit model and full-wave electromagnetic simulations. In addition, the CRLH antenna and AMC array structure were fabricated and measurements were undertaken, which agreed well with the simulated ones. Therefore, the integrated design is highly suggested to be recognized in wireless body area network (WBAN) and medical applications.

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.

Analytical approach for CRLH-based antennas design

This paper presents an analytical model for CRLH (Composite Right-Left Handed) antennas preliminary design. The objective of this work is to develop a tool to estimate quickly the scattering and radiating characteristics of these CRLH-based structures. The analytical model provides thus a set of parameters which roughly fulfill desired requirements. Afterwards, the antenna designer can refine the CRLH-based antenna performances with full 3D electromagnetic simulation software.

Metamaterial CRLH Antennas on Silicon Substrate for Millimeter-Wave Integrated Circuits

The paper presents two composite right/left-handed (CRLH) coplanar waveguide (CPW) zeroth-order resonant (ZOR) antennas which were designed, processed, and electrically characterized for applications in the millimetric wave frequency range. Two CRLH antennas were developed forf=27 GHz andf=38.5, GHz, respectively. The CRLH antenna onf=27 GHz shows a return loss ofRL<−18.78 dB atf=26.88 GHz. The −3 dB radiation characteristic beamwidth was approximately 37° and the gain wasGi=2.82 dBi. The CRLH antenna onf=38.5 GHz has a return loss ofRL<−38.5 dB atf=38.82 GHz and the −3 dB radiation characteristic beamwidth of approximately 17°. The gains wereGi=1.08 dBi atf=38 GHz andGi=1.2 dBi atf=38.6 GHz. The maximum measured gain wasGi=1.75 dBi atf=38.2 GHz. It is, upon the authors' knowledge, the first report of millimeter wave CRLH antennas on silicon substrate in CPW technique for use in mm-wave monolithic integrated circuit.

Compact Zeroth-Order Resonant Antenna Based on Dual-Arm Spiral Configuration

A miniaturized and zeroth-order resonant composite right/left-handed (CRLH) antenna based on dual-arm spiral structure is presented. The proposed dual-arm spiral unit cell is able to implement and tailor the CRLH lumped elements easily in a compact fashion. Particularly, the gap coupling between the spiral arms contributes to the series capacitance C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</sub> and the metallic via-hole at the end of one arm results in the shunt inductance L <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</sub> . The resonant frequency and thus the miniaturization factor can be simply engineered by the spiral parameters that determine the corresponding circuit elements. The proposed CRLH antenna is composed of two unit cells, each of which occupies only 0.066λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> × 0.053λ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> at the operating frequency. From the experimental results, this compact antenna exhibits the dipole-like radiation patterns and has a peak gain of -0.53 dBi. The measured and simulated results are provided, and good agreement is achieved.

Transmission Line Modeling and Asymptotic Formulas for Periodic Leaky-Wave Antennas Scanning Through Broadside

It is shown, using three specific examples-a series fed patch (SFP) array, a phase reversal (PR) array and a composite right/left-handed (CRLH) antenna-that one-dimensional periodic leaky-wave antennas scanning through broadside build a class of leaky-wave antennas sharing qualitatively similar and quantitatively distinct dispersion and radiation characteristics. Based on an equivalent transmission line (TL) model using linearized series and shunt immittances to approximate the periodic (Bloch) antenna structure, asymptotic TL formulas for the characteristic propagation constant, impedance, energy, power and quality factor are derived for two fundamentally different near- and off-broadside radiation regimes. Based on these formulas, it is established that the total powers in the series and shunt elements are always equal at broadside, which constitutes one of the central results of this contribution. This equal power splitting implies a severe degradation of broadside radiation when only one of the two elements series or shunt efficiently contributes to radiation and the other is mainly dissipative. A condition for optimum broadside radiation is subsequently established and shown to be identical to the Heaviside condition for distortionless propagation in TL theory. Closed-form expressions are derived for the constitutive (LCRG) parameters of the TL model for the specific SFP, PR and CRLH antenna circuit models, and quantitative information on the validity range of the TL model is subsequently provided. Finally, full-wave simulation and measurement LCRG parameter extraction methods are proposed and validated.

Miniaturized Substrate Integrated Waveguide Slot Antennas Based on Negative Order Resonance

Miniaturized waveguide slot antennas using negative order resonance are proposed and developed in this paper. The design of these novel resonant-type antennas is based on the study of a composite right/left-handed (CRLH) substrate integrated waveguide (SIW) starting from the dispersion diagram and the equivalent circuit. These proposed CRLH resonators are realized by etching the interdigital slot on the surface of the SIW. The slot acts as a series capacitor as well as a radiator leading to a CRLH antenna application. Two types of slot antennas, which are open-ended and short-ended, respectively, are proposed and discussed. The short-ended antenna, which represents a quasi-quarter-wavelength resonator, is characterized by a cavity-backed slot antenna thus providing a high gain. On the other hand, the open-ended antenna exhibits a small size owing to a quasi-half-wavelength operation in the left-handed (LH) region. Four antennas with one or two unit cells are fabricated and measured. Compared with the existing CRLH patch antennas and waveguide slot antennas, our antennas show advantages in terms of simplicity, low-profile, high efficiency, easy fabrication and integration with other circuits.

High Gain Patch Antenna with Composite Right-Left Handed Structure and Dendritic Cell Metamaterials

We present a novel high-gain patch antenna utilizing composite right-left handed (CRLH) structure and dendritic cell metamaterials. The proposed CRLH antenna, composed of modified Sievenpiper mushroom unit-cells, is based on the positive first-order resonance mode for high gain. In addition, the dendritic cell metamaterials are used to surround the proposed antenna to further increase the antenna directivity and gain due to suppressing the surface waves. The experimental results show that the gain and the directivity of the proposed antenna with CRLH and dendritic cells can be improved by 3.88 dB and 8.82, respectively, in comparison with a conventional patch antenna. Moreover, a 10-dB bandwidth with 9.55% is achieved. The measured results are in good agreement with the simulated ones.

CRLH metamaterial leaky-wave and resonant antennas

Composite right-/left-handed (CRLH) transmission-line (TL) metamaterials, with their rich dispersion and fundamental right-/left-hand duality, represent a paradigm shift in electromagnetics engineering and, in particular, for antennas. This paper presents an overview of the most practical leaky-wave and resonant CRLH antennas, which all exhibit functionalities or/and performance superior to prior state of the art. The leaky-wave antennas provide full-space dynamic scanning capability, with fan beams, conical beams in uni-planar configurations, pencil beams without any complex feeding network, and actively shaped beams based on the concept of aperture digitization. The resonant antennas offer alternative properties and a solution to beam-squinting when no scanning is required, including multi-band (dual/tri-band) operation, zeroth-order high efficiency, high directivity, and planar electric and magnetic monopole radiators.

A reflectodirective system using a composite right/left-handed (CRLH) leaky-wave antenna and heterodyne mixing

This letter presents a novel reflecto-directive system using a composite right/left-handed (CRLH) leaky-wave (LW) antenna and heterodyne mixing. The system receives a signal at a fixed frequency with a patch antenna and reflects it back toward any desired angle by tuning the LO frequency of a mixer. The performances of the system are demonstrated experimentally: 5 GHz incoming signals at -30/spl deg/, 0/spl deg/ and +30/spl deg/ are detected and transmitted, or reflected, to -20/spl deg/ at 3.5 GHz, +20/spl deg/ at 4.5 GHz and +50/spl deg/ at 5.5 GHz in agreement with the angle-frequency relationship of the CRLH antenna.