Meander Line Structure Research Articles

Wide-band superconducting coplanar delay lines

Two 25-ns high-temperature superconductor delay lines with novel double-spiral meander line structures were fabricated and measured, one based on the conventional coplanar waveguide (CPW) and the other based on the conductor-backed CPW. Compared with other published studies, the performance of the Conductor-backed CPW delay line is among the best in terms of the widest resonance-free band (2-18 GHz), low insertion loss (0.06 dB/ns at 60 K and 10 GHz), small ripple (<1 dB up until 16 GHz), and small dispersion (<2 ns in the variation of group delay between 2-18 GHz). This is also the first coplanar delay line successfully demonstrated without using wire bonding. The reflecting elements in the delay lines were identified through time-domain measurements. Full-wave simulations were performed to compare the double-spiral meander-line structure with conventional double-spiral line, and to identify the geometric factors restricting the bandwidth of the double-spiral meander line.

Radiation and ohmic resistances in very small meander line antennas of less than 0.1 wavelength

AbstractDemands for extremely small antennas to be used in radiofrequency identification tags for ubiquitous communication have increased. Examples of very small antennas utilizing meander line structures are seen. To date, important studies have been carried out on basic design and on improvement of the radiation efficiency by a folded configuration. Most of the structures studied have dimensions of more than 0.1 wavelength. For the demands of ultracompact antennas, this paper deals with meander line antennas whose dimensions are less than 0.1 wavelength. First, the parameters for resonant configurations are derived for antennas with dimensions of 0.1 to 0.025 wavelength. Next, the radiation resistance and the ohmic resistance are studied in the folded structures. First, through a transmission line model analysis, it is shown that the step‐up ratios of radiation and ohmic resistances in the case of folded structures are different. In addition, these resistances that are basic values of electrical performances are derived through electromagnetic simulations. Further, in order to confirm the validity of the numerical results and the realizable performance, antennas with dimensions of 0.1 and 0.05 wavelength were fabricated. Electrical characteristics are compared, and good agreements are found. © 2005 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 88(8): 1–11, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20204

A new type of parts feeder driven by bimorph piezo actuator

A novel meander-line structure implemented with bimorph piezoelectric actuators driven by two sets of alternating current power with phase difference is developed in this article. Via the generated traveling wave, this mechanism is able to transport parts. The dynamic modeling of the structure, the driving control circuitry design, the motion trajectory analysis and the optimal transport feed rate is studied, and also verified by the practical experiment.

Stress-impedance effects in layered FeSiB/Cu/FeSiB films with a meander line structure

Stress-impedance (SI) effects were realized in layered FeSiB/Cu/FeSiB films with a meander line structure by magnetron sputtering on thin glass substrate. The SI effects were studied in the frequency range of 1–40 MHz for the layered FeSiB/Cu/FeSiB films with different film thickness of FeSiB film and Cu layer. Experimental results show that the values of SI ratio increase nearly linear with the deflection of the layered FeSiB/Cu/FeSiB films at high frequencies, and a large negative SI ratio of - 18.3 % at a frequency of 25 MHz with the deflection of 1000 μ m is obtained in the layered FeSiB/Cu/FeSiB films with a thicker FeSiB film, which is very attractive for the applications of stress sensors.

Evaluation of flux guide performance in a SQUID microscope

We have developed a high-TC scanning SQUID microscope. In order to improve its spatial resolution a permalloy needle was used as a flux guide. The flux guide makes it possible to measure samples in air at room temperature. The magnetic field pattern of printed characters with linewidth of the order 100 µm was imaged well. We have investigated the performance of the flux guide both experimentally and numerically. The expected line scan image of a meander line structure was calculated using the three-dimensional finite element method and was found to agree reasonably well with the experimental data.

Performance of high-temperature superconducting band-pass filters with high selectivity for base transceiver applications of digital cellular communication systems

Highly selective high-temperature superconducting band-pass filters based on spiral meander line structures have been developed for base transceiver station applications of digital cellular communication systems. The filter comprised 12-pole microstrip line resonators with a circuit size of 0.5 × 17 × 41 mm3. The filter was designed to have a bandwidth of 25 MHz at a centre frequency of 834 MHz. Particularly, the physical size of each resonator was chosen not only to reduce far-field radiation, but also to have reasonable tunability in the filter. Device characteristics exhibited a low insertion loss of 0.4 dB with a 0.2 dB ripple and a return loss better than 10 dB in the pass-band at 65 K. The out-of-band signals were attenuated better than 60 dB at about 3.5 MHz from the lower band edge, and 3.8 MHz from the higher band edge.

Unit cell approach to full-wave analysis of meander delay line using FDTD periodic structure modeling method

Unit cell modeling is performed to determine the effect of electromagnetic coupling on the propagation characteristics of a meander delay line, which is widely used in printed circuit boards and packages. Since the design of a delay line must guarantee several tens of picosecond timing margin in modern high-speed packages and board level interconnections, a penetrating understanding of the meander effect is essential. The propagation delay, the characteristic impedance, and the stop-band characteristic of the meander delay line have been carefully investigated based on a full-wave analysis using the finite-difference time-domain (FDTD) periodic structure modeling method. The periodicity of the meander line is utilized based on Floquet's theorem, resulting in a reduction of the computational domain in the FDTD simulation and providing a unit cell model of the meander line. The unit cell modeling of the meander delay line shows the effect of electromagnetic coupling in meander line structure on the reduction of the propagation delay. Also, an analysis based on the unit cell modeling was confirmed by time-domain reflection/transmission measurements.

Superconducting half-wave microwave resonator on YSZ buffered Si [100

We have produced high quality superconducting half-wave microwave resonators on YBCO/YSZ/Si heterostructures. The YSZ was grown on [100] Si by pulsed dc magnetron sputtering at 820/spl deg/C in 37 mTorr Ar/O/sub 2/. YBCO was then deposited on the YSZ/Si by pulsed laser ablation at 760/spl deg/C in 0.5 Torr of O/sub 2/. A coplanar meander-line structure was patterned and its microwave characteristics measured. The results indicate Si to be a definite candidate for microwave applications producing Q values exceeding 50,000 at 4 GHz for T<30 K. The microwave properties compare favorably to those obtained from identical resonators patterned on normal metal and YBCO/LaAlO/sub 3/ at 30 K.

Analysis of multilayered meander line polarizer

In this paper, we present an analysis of a multilayered meander line polarizer. Using waveguide modal fields and Galerkin's method of moments, the equivalent susceptance of a meander line screen is determined. The equivalent susceptance includes the effect of the dielectric layers that are present in the close vicinity of the meander line plane. The transmission matrix formulation then is invoked to find the transmission and reflection behavior of a multilayered meander line structure. Numerical results for equivalent susceptance, return loss, and axial ratio are found to compare well with the measured data. Performance characteristics of multilayered meander line polarizers are studied, and the results are presented. © 1997 John Wiley & Sons, Inc. Int J Microwave Millimeter-Wave CAE 7: 442–454, 1997.

YBCO/ferrite low-loss microwave phase shifter

Microstrip-geometry phase shifters have limited use at microwave frequencies because of high insertion losses resulting from resistance in the metal conductors. We report a phase shifter fabricated from a YBa/sub 2/Cu/sub 3/O/sub 7-x/ microstrip line on LaAlO/sub 3/ coupled to a ferrite toroid. The magnetic flux required for gyromagnetic interaction with the microwave signal is contained within the closed magnetic path of the ferrite toroid so that the superconductor encounters a very low external magnetic field. Initial measurements at 77 K using a meanderline structure to provide nonreciprocal operation have demonstrated greater than 700 deg of differential phase shift at 10 GHz in a compact structure 2.5 cm long by 0.5 cm wide. The insertion loss is smaller than 0.7 dB which yields a figure of merit considerably greater than 1000 deg/dB. The best conventional phase shifters have an estimated figure of merit of 300 deg/dB at 77 K. Potential radar system applications and improvements in the figure of merit are discussed.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Epitaxial Superconductor Film Growth on Ultratffln Silicon Wafers for Infrared Detection

ABSTRACTEpitaxial YBCO/YSZ thin films have been successfully grown on ultrathin Si(100) wafers as part of an effort to fabricate infrared detectors which are both fast and highly responsive. Single crystal Si wafers with thicknesses ranging from 400 μm to 3μm are used as growth substrates. Detectors are fabricated by patterning the YBCO films into meanderline structures and their IR response is evaluated as a function of substrate thickness. So far, we have achieved a responsivity of 1750 V/W with a 10 Hz chopping rate on the 25 μm substrate, and rise/fall times as fast as 3 msec on the 3 μm substrate. We have also measured the low temperature IR transmission from 15 μm to 300 μm of both the YSZ buffered Si substrate, and the complete YBCO/YSZ/Si sample. This study indicates that silicon is a superior substrate for the fabrication of high performance infrared focal plane detector arrays.

Measurement of the surface resistance Rs of structured Y-Ba-Cu-O films on different substrates in the lower gigahertz range

A method for measuring the average surface resistance Rs of high-Tc superconducting thin-film strips on different substrates in the lower gigahertz range is presented. The method is based on quality factor measurements of a half-wavelength meanderline resonator in inverted microstrip form. The quality factor depends on the Rs of the conductor and the loss factor tan delta of the substrate. The evaluation takes into account the coupling between the neighbouring lines of the meanderline structure. Special geometrical dimensions allow the measurement of the quality factor between 15 K and the critical temperature. The surface resistance of the conducting material can be determined from the relation for the quality factor using a numerical program. Measurements were carried out between 0.5 and 4.0 GHz with Y1Ba2Cu3O7 films on Al2O3, YSZ, MgO and LaAlO3. Best Rs values were obtained on LaAlO3 around 0.5 m Omega at 77 K and 0.760 GHz.

Tunable magnetostatic surface wave demultiplexing filter/switch

A tunable frequency demultiplexing filter/switch has been realised on a magnetostatic surface wave delay line by employing both parallel-bar structure and meander line structure as output transducers together with a wideband single-line input transducer. Switching from one output terminal to the other has been obtained by changing the applied magnetic field from 57 Oe to 78 Oe at 1.1 GHz.