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Coplanar waveguide circuits, components, and systems

01 Jan 2001-
TL;DR: In this paper, the authors describe the characteristics of conventional, Micromachined, and Superconducting Coplanar Waveguides, as well as their transitions in directional couplers, hybrid, and magic-Ts.
Abstract: Preface Introduction Conventional Coplanar Waveguide Conductor-Backed Coplanar Waveguide Coplanar Waveguide with Finite-Width Ground Planes Coplanar Waveguide Suspended Inside A Conducting Enclosure Coplanar Striplines Microshield Lines and Coupled Coplanar Waveguide Attenuation Characteristics of Conventional, Micromachined, and Superconducting Coplanar Waveguides Coplanar Waveguide Discontinuities and Circuit Elements Coplanar Waveguide Transitions Directional Couplers, Hybrids, and Magic-Ts Coplanar Waveguide Applications References Index
Citations
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Journal ArticleDOI
TL;DR: The field of circuit quantum electrodynamics (QED) as discussed by the authors was initiated by Josephson-junction-based superconducting circuits and has become an independent and thriving field of research in its own right.
Abstract: Quantum-mechanical effects at the macroscopic level were first explored in Josephson-junction-based superconducting circuits in the 1980s. In recent decades, the emergence of quantum information science has intensified research toward using these circuits as qubits in quantum information processors. The realization that superconducting qubits can be made to strongly and controllably interact with microwave photons, the quantized electromagnetic fields stored in superconducting circuits, led to the creation of the field of circuit quantum electrodynamics (QED), the topic of this review. While atomic cavity QED inspired many of the early developments of circuit QED, the latter has now become an independent and thriving field of research in its own right. Circuit QED allows the study and control of light-matter interaction at the quantum level in unprecedented detail. It also plays an essential role in all current approaches to gate-based digital quantum information processing with superconducting circuits. In addition, circuit QED provides a framework for the study of hybrid quantum systems, such as quantum dots, magnons, Rydberg atoms, surface acoustic waves, and mechanical systems interacting with microwave photons. Here the coherent coupling of superconducting qubits to microwave photons in high-quality oscillators focusing on the physics of the Jaynes-Cummings model, its dispersive limit, and the different regimes of light-matter interaction in this system are reviewed. Also discussed is coupling of superconducting circuits to their environment, which is necessary for coherent control and measurements in circuit QED, but which also invariably leads to decoherence. Dispersive qubit readout, a central ingredient in almost all circuit QED experiments, is also described. Following an introduction to these fundamental concepts that are at the heart of circuit QED, important use cases of these ideas in quantum information processing and in quantum optics are discussed. Circuit QED realizes a broad set of concepts that open up new possibilities for the study of quantum physics at the macro scale with superconducting circuits and applications to quantum information science in the widest sense.

773 citations


Cites background from "Coplanar waveguide circuits, compon..."

  • ... described by its characteristic impedance Zr= p l0=c0 and the speed of light in the waveguide v0 = 1= p l0c0, where we have introduced the capacitance to ground c0 and inductance l0 per unit length (Simons, 2001). Typical values of these parameters are Zr˘50 and v0 ˘1:3 108 m/s, or about a third of the speed of light in vacuum (Goppl et al., 2008). For a given substrate, metal thickness and center conductor ...

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  • ...s, 2001). In the coplanar waveguide geometry, transmission lines of constant impedance Zr can therefore be realized for varying center conductor width wby keeping the ratio of w=sclose to a constant (Simons, 2001). This allows the experimenter to fabricate a device with large wat the edges for convenient interfacing, and small waway from the edges to minimize the mode volume or simply for miniaturization. A re...

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  • ...coplanar waveguide of nite length formed by a center conductor of width wand thickness t, separated on both sides by a distance sfrom a ground plane of the same thickness, see Fig. 2(a) (Pozar, 2012; Simons, 2001). Both conductors are typically deposited on a low-loss dielectric substrate of permittivity "and thickness much larger than the dimensions w;s;t. This planar structure acts as a transmission lin...

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Journal ArticleDOI
TL;DR: Sub-nanosecond switching of a metal-oxide-metal memristor utilizing a broadband 20 GHz experimental setup developed to observe fast switching dynamics is reported.
Abstract: We report sub-nanosecond switching of a metal?oxide?metal memristor utilizing a broadband 20?GHz experimental setup developed to observe fast switching dynamics. Set and reset operations were successfully performed in the tantalum oxide memristor using pulses with durations of 105 and 120?ps, respectively. Reproducibility of the sub-nanosecond switching was also confirmed as the device switched over consecutive cycles.

632 citations


Cites methods from "Coplanar waveguide circuits, compon..."

  • ...Such a transmission line configuration has been utilized in highfrequency circuits [19] as well as in the high-frequency evaluation of nanodevices such as carbon nanotubes [20], nanowires [21], and graphene [22]....

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Journal ArticleDOI
20 Sep 2004
TL;DR: The scientific opportunities, the basic physics of these devices, the techniques for radiation coupling, and the recent progress in direct detectors are described, as well as the work on tunnel junction (superconductor-insulator-super Conductor) and hot-electron mixers.
Abstract: Superconducting detectors will play an increasingly significant role in astrophysics, especially at millimeter through far-IR wavelengths, where the scientific opportunities include key problems in astronomy and cosmology. Superconducting detectors offer many benefits: outstanding sensitivity, lithographic fabrication, and large array sizes, especially through the recent development of multiplexing techniques. This paper describes the scientific opportunities, the basic physics of these devices, the techniques for radiation coupling, and reviews the recent progress in direct detectors, such as transition-edge bolometers, and the work on tunnel junction (superconductor-insulator-superconductor) and hot-electron mixers.

307 citations


Cites methods from "Coplanar waveguide circuits, compon..."

  • ...which consist of high- thin-film microwave resonators, using coplanar waveguide transmission lines [144] for example....

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Journal ArticleDOI
TL;DR: A sensor based on a coplanar waveguide structure was designed to perform non-destructive tests for material characterization in which the measurement can be done only on one side of the sample.
Abstract: A sensor based on a coplanar waveguide structure was designed to perform non-destructive tests for material characterization in which the measurement can be done only on one side of the sample. The measurements were compared with the impedance of a capacitor filled with the same material. The permittivity and insertion loss of the sensor showed valuable information about the setting process of a mortar slab during the first 28 days of the hardening process, and a good correlation between both measurements was obtained, so the proposed setup can be useful for structural surveillance and moisture detection in civil structures.

289 citations

DissertationDOI
01 Jan 2008
TL;DR: In this article, the authors explored the properties of microwave kinetic inductance detectors (MKID) and their properties of excess frequency noise, including power, temperature, material, and geometry dependence.
Abstract: Over the past decade, low temperature detectors have brought astronomers revolutionary new observational capabilities and led to many great discoveries. Although a single low temperature detector has very impressive sensitivity, a large detector array would be much more powerful and are highly demanded for the study of more difficult and fundamental problems in astronomy. However, current detector technologies, such as transition edge sensors and superconducting tunnel junction detectors, are difficult to integrate into a large array. The microwave kinetic inductance detector (MKID)is a promising new detector technology invented at Caltech and JPL which provides both high sensitivity and an easy solution to the detector integration. It senses the change in the surface impedance of a superconductor as incoming photons break Cooper pairs, by using high-Q superconducting microwave resonators capacitively coupled to a common feedline. This architecture allows thousands of detectors to be easily integrated through passive frequency domain multiplexing. In this thesis, we explore the rich and interesting physics behind these superconducting microwave resonators. The first part of the thesis discusses the surface impedance of a superconductor, the kinetic inductance of a superconducting coplanar waveguide, and the circuit response of a resonator. These topics are related with the responsivity of MKIDs. The second part presents the study of the excess frequency noise that is universally observed in these resonators. The properties of the excess noise, including power, temperature, material, and geometry dependence, have been quantified. The noise source has been identified to be the two-level systems in the dielectric material on the surface of the resonator. A semi-empirical noise model has been developed to explain the power and geometry dependence of the noise, which is useful to predict the noise for a specified resonator geometry. The detailed physical noise mechanism, however, is still not clear. With the theoretical results of the responsivity and the semi-empirical noise model established in this thesis, a prediction of the detector sensitivity (noise equivalent power) and an optimization of the detector design are now possible.

245 citations


Cites background from "Coplanar waveguide circuits, compon..."

  • ...The resonance at 2fr is very likely to come from the coupled slotline mode (also called the odd mode) of CPW line[71]....

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References
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Journal ArticleDOI
C.P. Wen1
05 May 1969
TL;DR: In this article, the coplanar waveguide is used for non-reciprocal magnetic device applications because of the built-in circularly polarized magnetic vector at the air-dielectric boundary between the conductors.
Abstract: A coplanar waveguide consists of a strip of thin metallic film on the surface of a dielectric slab with two ground electrodes running adjacent and parallel to the strip. This novel transmission line readily lends itself to nonreciprocal magnetic device applications because of the built-in circularly polarized magnetic vector at the air-dielectric boundary between the conductors. Practical applications of the coplanar waveguide have been experimentally demonstrated by measurements on resonant isolators and differential phase shifters fabricated on low-loss dielectric substrates with high dielectric constants. Calculations have been made for the characteristic impedance, phase velocity, and ripper bound of attenuation of a transmission line whose electrodes are all on one side of a dielectric substrate. These calculations are in good agreement with preliminary experimental results. The coplanar configuration of the transmission system not only permits easy shunt connection of external elements in hybrid integrated circuits, but also adapts well to the fabrication of monolithic integrated systems. Low-loss dielectric substrates with high dielectric constants may be employed to reduce the longitudinal dimension of the integrated circuits because the characteristic impedance of the coplanar waveguide is relatively independent of the substrate thickness; this may be of vital importance for Iow-frequency integrated microwave systems.

910 citations

Journal ArticleDOI
TL;DR: In this paper, a frequency-dependent hybrid-mode analysis of single and coupled slots and coplanar strips is presented, where the dispersion characteristic and characteristic impedance of the structures are obtained by applying a Fourier transform technique and evaluating the resulting expressions numerically using the method of moments.
Abstract: A frequency-dependent hybrid-mode analysis of single and coupled slots and coplanar strips is presented. The dispersion characteristic and characteristic impedance of the structures are obtained by applying a Fourier transform technique and evaluating the resulting expressions numerically using the method of moments. Numerical results are presented and compared with results published by other investigators. The experimental performance of a slot-line coupler is compared with predicted performance based upon the results presented here for coupled slots. Excellent agreement has been obtained in all cases.

264 citations


"Coplanar waveguide circuits, compon..." refers background or methods in this paper

  • ...[21] Agilent Technologies, Santa Clara, California....

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  • ...In addition electromagnetic simulation software for 2-D and 3-D structures have also become commercially available [21] to [25]....

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  • ...In [20] and [21] the CPW was analyzed by modeling the structure as a capacitive iris in a rectangular waveguide....

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  • ...The computed is based on the model reported in [21]....

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Journal ArticleDOI
TL;DR: In this article, a new "uniplanar" circuit configuration for monolithic microwave integrated circuits (MMICs) has been proposed, which uses a combination of coplanar waveguides and slotlines on one side of the substrate.
Abstract: A new "uniplanar" circuit configuration for monolithic microwave integrated circuits (MMIC's) has been proposed. It uses a combination of coplanar waveguides and slotlines on one side of the substrate. The key components for the uniplanar structure are air bridges, which provide T junctions and transitions from coplanar waveguides to slotlines or vice versa. Novel hybrid circuits such as a magic T and a branch-line coupler have been fabricated and tested at K-band, and good performance has been achieved. This new circuit configuration is promising for applications in other microwave circuits.

160 citations


"Coplanar waveguide circuits, compon..." refers background in this paper

  • ...However, in the analysis presented in [45], [46] and [47] conductor thickness is taken into account....

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  • ...In [45] it has been shown that the effect of t on Z is smaller for substrates of higher dielectric constant....

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  • ...CPW MEMS shunt switches with good insertion loss characteristics, reasonable switching voltages, fast switching speed, and excellent linearity have recently been demonstrated [45]....

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  • ...the conductors are located on the top surface of a substrate which makes it ideally suited for fabricating metal membrane, capacitive, shunt-type switches [45]....

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  • ...In [45] it has been shown that the effect of t on is larger for substrates of higher dielectric constant....

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Journal ArticleDOI
TL;DR: In this article, the authors examined the conductor loss and effective dielectric constant of microshield lines and presented results on transitions to conventional coplanar waveguide, right-angle bends, different stub configurations, and lowpass and bandpass filters.
Abstract: Several millimeter-wave passive components have been fabricated using the microshield transmission line geometry, and their performance is presented herein. Microshield is a quasi-planar, half-shielded design which uses a thin dielectric membrane (1.5 /spl mu/m) to support the conducting lines. This approach provides a nearly homogeneous, air-filled environment and thus allows extremely broad-band TEM operation. This paper examines the conductor loss and effective dielectric constant of microshield lines and presents results on transitions to conventional coplanar waveguide, right-angle bends, different stub configurations, and lowpass and bandpass filters. Experimental data is provided along with numerical results derived from an integral equation method. The microshield line is shown to be very suitable for high performance millimeter and submillimeter-wave applications. >

153 citations

Journal ArticleDOI
TL;DR: In this paper, the authors describe the development and characterization of a new class of Si-micromachined lines and circuit components for operation between 2-110 GHz, which are a finite-ground coplanar-waveguide (FGC) type, Si micromachining is used to remove the dielectric material from the aperture regions in an effort to reduce dispersion and minimize propagation loss.
Abstract: This paper describes the development and characterization of a new class of Si-micromachined lines and circuit components for operation between 2-110 GHz. In these lines, which are a finite-ground coplanar-waveguide (FGC) type, Si micromachining is used to remove the dielectric material from the aperture regions in an effort to reduce dispersion and minimize propagation loss. Measured results have shown a considerable loss reduction to levels that compare favorably with those of membrane lines and rectangular waveguides. Micromachined FGC lines have been used to develop V- and W-band bandpass filters. The W-band micromachined FGC filter has shown a 0.8-dB improvement in insertion loss at 94 GHz over a conventional FGC line. This approach offers an excellent alternative to the membrane technology, exhibiting very low loss, no dispersion, and mode-free operation without using membranes to support the interconnect structure.

146 citations


"Coplanar waveguide circuits, compon..." refers background in this paper

  • ...The CPW amplifier circuits include millimeter-wave amplifiers [26], [27], distributed amplifiers [28], [29], cryogenically cooled amplifiers [30], cascode amplifiers [31], transimpedance amplifiers [32], dual gate HEMT amplifiers [33], and low-noise amplifiers [34]....

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  • ...A similar set of equations was presented in [29]....

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  • ...A practical solution to this problem is to tie the top ground plane to the bottom conductor by metal-filled via holes [8], [28], [29]....

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