Metamaterial Phase Shifter Research Articles

Ultra-short and highly efficient metamaterial Fresnel lens-assisted taper.

This paper demonstrates the benefits of leveraging free-space optics concepts in the design of certain integrated photonic components, leading to a footprint reduction without compromising on performance. Specifically, we present ultra-short, highly efficient and fabrication-friendly mode-size converters based on metamaterial Fresnel lens-assisted tapers. This is achieved using a parameterized inverse-design approach, where the metamaterial phase shifters are realized using fabrication-friendly Manhattan geometries, by optimizing the width, length, and position of the phase shifters. This approach overcomes the limitations of the conventional method that uses local periodic approximation, which is not suitable for lenses with a short focal length and high numerical aperture. We also extend the free-space concept of compound lenses and demonstrate a doublet-based taper to further reduce the footprint. The devices are fabricated and experimentally characterized in terms of insertion loss and signal integrity at high data transmission rates, exhibiting high performance. For the singlet, it effectively achieves mode-size conversion from 15 μm to 0.5 μm within a 15 μm distance, leading to ×10 length reduction compared to a linear taper. The insertion loss is under 1 dB over the entire C-band. The doublet achieves the same mode-size reduction within a 10 μm distance, leading to ×15 length reduction compared to a linear taper. The insertion loss is near 1 dB over most of the C-band. In both cases, the signal integrity is maintained for up to 50 Gbit/s.

A Flexible Conformal Phased Array With Embedded Magnetic Particles Based Composite Right/Left Handed Metamaterial Phase Shifters

A Flexible Conformal Phased Array With Embedded Magnetic Particles Based Composite Right/Left Handed Metamaterial Phase Shifters

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.

Reconfigurable inductorless negative‐refractive‐index transmission‐line metamaterial phase shifter for 5G antenna beam‐steering applications

AbstractA reconfigurable inductorless negative‐refractive‐index transmission‐line (NRI‐TL) metamaterial phase shifter for sub‐6 GHz 5G antenna applications is proposed. The design consists of a microstrip transmission line loaded both in series and in parallel with varactor diodes to provide continuous tuning of the phase of the transmitted signal by varying the bias voltage applied to the varactors, without the need for variable inductor components. The total measured differential phase shift is 190° at 3.2 GHz, with a measured insertion loss of 1.5–2.7 dB in the frequency range of 3.2–3.6 GHz, when the biasing voltage of the varactors is varied between 0 and 7 V. The total size of the microstrip NRI‐TL phase shifter is 19.4 mm × 24 mm. The proposed reconfigurable phase shifter has been incorporated into the feeding network of a two‐element antenna array to demonstrate its use in beam‐steering applications. The measured results for the reconfigurable array show good impedance matching between 3 and 3.35 GHz for all biasing values, allowing continuous beam steering over a scanning range of 60°.

Terahertz Fresnel-zone-plate thin-film lens based on a high-transmittance double-layer metamaterial phase shifter.

Planar diffractive lenses, with metamaterial artificial structures and subwavelength thickness, provide unique and flexible platforms for optical design in the terahertz (THz) regime. Here, we present a metamaterial-based Rayleigh-Wood Fresnel-zone-plate (FZP) thin-film lens designed to focus a monochromatic THz beam at 1.0 THz with a high transmittance of 80%, short focal length of 24 mm, and subwavelength thickness of 48 µm. Specifically, the FZP lens is composed of 8 alternating concentric zones through a polymer film substrate, where odd zones are patterned with double-layer un-split ring resonators (USRRs) that provide a polarization-independent phase shift of π/2 compared to un-patterned even zones. Both simulation and experiment confirm that our FZP lens creates a focused beam at the designed frequency of 1.0 THz by constructive interference through alternating concentric metamaterial-patterned and un-patterned zones, producing a diffraction-limited resolution of 0.6 mm for imaging applications. In contrast to conventional approaches in which the uniform periodic array of metamaterial unit cells has been treated as an effective material, we newly find that double-layer USRRs can work as an independent meta-atom without degradation of its performances, which benefits the behavior of small arrays of double-layer USRRs located in the outer zones of the FZP lens. Such a planar thin-film lens would enable us to realize compact and lightweight THz systems.

A novel ultra‐miniature 90° metamaterial phase shifter for beamforming applications

AbstractIn radiofrequency (RF) applications, reducing the structure size of the phase shifter (PS) other remains a key challenge. In this article, a new compact‐wilds‐phase shifter for reducing the size area of the conventional design has been introduced. Unlike, conventional shifter, the proposed one leverages metamaterial for size reduction by using complementary split ring resonator. It operates at central frequency 2.4 GHz. The experimental results showed that the proposed design can significantly reduce 66% from the size of conventional structure.

Zero Meta-material Ferroelectric Phase Shifter Embedded inside LTCC

This paper describes the design and processing of a zero meta-material phase shifter (ZMPS) embedded within a low temperature co-fired ceramics (LTCC) structure. The designed ZMPS is based on a composite right/left handed meta-material (CRLH MTM) transmission line approach. L-C networks were used to achieve zero phase shift at a specified frequency. The proposed design combines the advantages of an accurate zero phase shift using meta-material concepts and the advantages of passive components (capacitors and inductors) embedded inside LTCC to reduce device size, weight, and cost. The designed phase shifter provides an accurate 0o phase shift at 0.73 GHz with −16.7 dB return-loss and −0.31 dB insertion-loss at the center frequency. The paper also provides a comparison between BST and BZT as dielectric materials embedded inside LTCC with respect to the preparation process and shrinking effects.

A New Low Cost Leaky Wave Coplanar Waveguide Continuous Transverse Stub Antenna Array Using Metamaterial-Based Phase Shifters for Beam Steering

In this paper, we have proposed a new leaky-wave coplanar waveguide (CPW) continuous transverse stub (CTS) antenna array with metamaterial-based phase shifters for beam steering applications. The array integrates three CTS elements and two 6-stage negative reflective index (NRI) phase shifters, and is fed by CPW transmission line. Beam steering capabilities are achieved by tuning the values of the NRI phase shifters. The proposed CPW-CTS array is fabricated for 2.4-GHz wireless local area network (WLAN). The measured data, including parameters, radiation patterns and gain, agree well with the simulation results. A scan-angle range from 58 to 124 of unidirectional radiation pattern is measured in the -plane with good impedance matching (-1 dB ). Designs incorporating continuous beam steering using tunable NRI metamaterial phase shifters are also discussed.

Composite right/left-handed transmission line metamaterial phase shifters (MPS) in MMIC technology

This paper presents the modeling and design of one-dimensional metamaterial phase shifters (MPSs) in monolithic-microwave integrated-circuit technology based on the composite right/left-handed transmission-line approach. From a theoretical point-of-view, we show that existing design expressions are restricted to phase shifters behaving as effective media, which is the case only if sufficiently large L and C loading elements can be designed in the given technology and at the frequency of interest. Therefore, we propose new design expressions, which are exact on the basis of the circuit model of a unit cell in the structure. We show that the new expressions must be used to design integrated MPSs and the theory is verified by means of measurements of one- and two-cell phase shifters exhibiting a 0/spl deg/ phase shift at 17.5GHz. The designed one-cell phase shifter provides a -10-dB input return-loss bandwidth larger than 10% with phase shifts of +29/spl deg/ and -30/spl deg/ at 16.5 and 18.5 GHz, respectively. The insertion loss is -1.3 dB at the center frequency and -1.7 dB at the limit of the bandwidth.

Compact linear lead/lag metamaterial phase shifters for broadband applications

A compact one-dimensional phase shifter is proposed using alternating sections of negative refractive index (NRI) metamaterials and printed transmission lines (TL). The NRI metamaterial sections consist of lumped element capacitors and inductors, arranged in a dual TL (high-pass) configuration. By adjusting the NRI-medium lumped element values, the phase shift can be tailored to a given specification. Periodic analysis is applied to the structure and design equations are presented for the determination of the lumped element parameters for any arbitrary phase shift. To validate the design, various phase shifters are simulated and tested in coplanar waveguide (CPW) technology. It is demonstrated that small variations in the NRI-medium lumped element values can produce positive, negative or 0/spl deg/ phase shifts while maintaining the same short overall length. Thus, the new phase shifter offers some significant advantages over conventional delay lines: it is more compact in size, it exhibits a linear phase response around the design frequency, it can incur a phase lead or lag which is independent of the length of the structure and it exhibits shorter group delays.