Showing papers on "Coplanar waveguide published in 2012"

Planar superconducting resonators with internal quality factors above one million

Abstract: We describe the fabrication and measurement of microwave coplanar waveguide resonators with internal quality factors above 107 at high microwave powers and over 106 at low powers, with the best low power results approaching 2×106, corresponding to ∼1 photon in the resonator. These quality factors are achieved by controllably producing very smooth and clean interfaces between the resonators’ aluminum metallization and the underlying single crystal sapphire substrate. Additionally, we describe a method for analyzing the resonator microwave response, with which we can directly determine the internal quality factor and frequency of a resonator embedded in an imperfect measurement circuit.

Planar Superconducting Resonators with Internal Quality Factors above One Million

Abstract: We describe the fabrication and measurement of microwave coplanar waveguide resonators with internal quality factors above 10 million at high microwave powers and over 1 million at low powers, with the best low power results approaching 2 million, corresponding to ~1 photon in the resonator. These quality factors are achieved by controllably producing very smooth and clean interfaces between the resonators' aluminum metallization and the underlying single crystal sapphire substrate. Additionally, we describe a method for analyzing the resonator microwave response, with which we can directly determine the internal quality factor and frequency of a resonator embedded in an imperfect measurement circuit.

Microwave characterization of Josephson junction arrays: implementing a low loss superinductance.

Abstract: We have measured the plasma resonances of an array of Josephson junctions in the regime E(J)>>E(C), up to the ninth harmonic by incorporating it as part of a resonator capacitively coupled to a coplanar waveguide. From the characteristics of the resonances, we infer the successful implementation of a superinductance, an electrical element with a nondissipative impedance greater than the resistance quantum [R(Q)=h/(2e)(2) is approximately equal to 6.5 kΩ] at microwave frequencies. Such an element is crucial for preserving the quantum coherence in circuits exploiting large fluctuations of the superconducting phase. Our results show internal losses less than 20 ppm, self-resonant frequencies greater than 10 GHz, and phase-slip rates less than 1 mHz, enabling direct application of such arrays for quantum information and metrology. Arrays with a loop geometry also demonstrate a new manifestation of flux quantization in a dispersive analog of the Little-Parks effect.

Multilayered circuit type antenna package

Abstract: A multilayered antenna package including: a radio frequency integrated circuit (RFIC) interface layer that is configured to transmit a radio frequency (RF) signal; a first dielectric layer that is disposed on the RFIC interface layer; a coplanar waveguide layer that is disposed on the first dielectric layer and is configured to receive the RF signal transmitted by RFIC layer; a second dielectric layer disposed on the coplanar waveguide layer; and an antenna portion that is disposed on the second dielectric layer and is configured to irradiate a signal that is transmitted from the coplanar waveguide layer.

Very Compact Printed Triple Band-Notched UWB Antenna With Quarter-Wavelength Slots

Abstract: A very compact coplanar waveguide (CPW)-fed ultrawideband (UWB) printed monopole antenna (PMA) with triple band-notched characteristics is presented. The antenna uses three open-ended quarter-wavelength slots to create triple band-notched characteristics in 3.3-3.7 GHz for WiMAX, 5.15-5.825 GHz for WLAN, and 7.25-7.75 GHz for downlink of X-band satellite communication systems, respectively. The open-ended quarter-wavelength slot is analyzed in detail. Surface current distributions are used to show the effect of these slots. The antenna shows broad bandwidth and good omnidirectional radiation patterns in the passband, with a very compact size of 19 × 24 mm2.

Guided Wave Applicator with Non-Gaseous Dielectric for Plasma Chamber

Abstract: A guided wave applicator comprising two electrically conductive waveguide walls and a waveguide dielectric. The volume of the waveguide dielectric is composed of non-gaseous dielectric material and is positioned between the two waveguide walls. The waveguide dielectric includes first and second longitudinal ends and includes first, second, third and fourth sides extending longitudinally between the two longitudinal ends. The first waveguide wall is positioned so that it covers the first side of the waveguide dielectric, and the second waveguide wall is positioned so that it covers the second side of the waveguide dielectric. In operation, electrical power can be supplied to one or both longitudinal ends of the waveguide dielectric, whereby the power can be coupled to a plasma through the exposed sides of the waveguide dielectric.

Alignment and Position Sensors Based on Split Ring Resonators

Abstract: In this paper compact alignment and position sensors based on coplanar waveguide (CPW) transmission lines loaded with split ring resonators (SRRs) are proposed. The structure consists of a folded CPW loaded with two SRRs tuned at different frequencies to detect both the lack of alignment and the two-dimensional linear displacement magnitude. Two additional resonators (also tuned at different frequencies) are used to detect the displacement direction. The working principle for this type of sensor is explained in detail, and a prototype device to illustrate the potential of the approach has been designed and fabricated.

Enhanced Electrical Conductivity of Silver Nanoparticles for High Frequency Electronic Applications

Abstract: An enhancement in the electrical performance of low temperature screen-printed silver nanoparticles (nAg) has been measured at frequencies up to 220 GHz. We show that for frequencies above 80 GHz the electrical losses in coplanar waveguide structures fabricated using nAg at 350 °C are lower than those found in conventional thick film Ag conductors consisting of micrometer-sized grains and fabricated at 850 °C. The improved electrical performance is attributed to the better packing of the silver nanoparticles resulting in lower surface roughness by a factor of 3. We discuss how the use of silver nanoparticles offers new routes to high frequency applications on temperature sensitive conformal substrates and in sub-THz metamaterials.

Strongly Disordered TiN and NbTiN s-Wave Superconductors Probed by Microwave Electrodynamics

Abstract: We probe the effects of strong disorder (2.4

An Equivalent Circuit Model of the Traveling Wave Electrode for Carrier-Depletion-Based Silicon Optical Modulators

Abstract: We propose an equivalent circuit model for the coplanar waveguide (CPW) which serves as the traveling wave electrode to drive carrier-depletion-based silicon modulators. Conformal mapping and partial capacitance techniques are employed to calculate each element of the circuit. The validity of the model is confirmed by the comparison with both finite-element simulation and experimental result. With the model, we calculate the modulation bandwidth for different CPW dimensions and termination impedances. A 3 dB modulation bandwidth of 15 GHz is demonstrated with a traveling wave electrode of 3 mm. The calculation indicates that, by utilizing a traveling wave electrode of 2 mm, we can obtain a 3 dB modulation bandwidth of 28 GHz.

CPW-Fed Cavity-Backed Slot Radiator Loaded With an AMC Reflector

Abstract: A low profile coplanar waveguide (CPW) fed printed slot antenna is presented with uni-directional radiation properties. The slot antenna radiates above a closely spaced artificial magnetic conducting (AMC) reflector consisting of an array of rectangular patches, a substrate and an electric ground plane. The electromagnetic bandgap (EBG) performance of the cavity structure between the upper conducting surface in which the slot is etched, and the ground plane at the bottom of the reflector, is investigated using an equivalent waveguide feed in the place of a half-wavelength section of the slot antenna. From the reflection coefficient of the equivalent waveguide feed one can determine the frequency band where minimum energy will be lost due to unwanted radiation from the cavity sides. The dimensions of the cavity were found to be very important for minimum energy loss. Experimental results for the final antenna design (with a size of 1.02λ0×0.82λ0×0.063λ0), mounted on a 1.5λ0×1.5λ0 back plate, exhibit a 5% impedance bandwidth, maximum gain in excess of 10 dBi, low cross-polarization, and a front-to-back ratio of approximately 25 dB. This low-profile antenna with relatively high gain could be a good candidate for a 2.4 GHz WLAN application.

Etch induced microwave losses in titanium nitride superconducting resonators

Abstract: We have investigated the correlation between the microwave loss and patterning method for coplanar waveguide titanium nitride resonators fabricated on silicon wafers. Three different methods were investigated: fluorine- and chlorine-based reactive ion etches and an argon-ion mill. At high microwave probe powers, the reactive etched resonators showed low internal loss, whereas the ion-milled samples showed dramatically higher loss. At single-photon powers, we found that the fluorine-etched resonators exhibited substantially lower loss than the chlorine-etched ones. We interpret the results by use of numerically calculated filling factors and find that the silicon surface exhibits a higher loss when chlorine-etched than when fluorine-etched. We also find from microscopy that re-deposition of silicon onto the photoresist and side walls is the probable cause for the high loss observed for the ion-milled resonators.

Driving Rydberg-Rydberg transitions from a coplanar microwave waveguide.

Abstract: The coherent interaction between ensembles of helium Rydberg atoms and microwave fields in the vicinity of a solid-state coplanar waveguide is reported. Rydberg-Rydberg transitions, at frequencies between 25 and 38 GHz, have been studied for states with principal quantum numbers in the range 30--35 by selective electric-field ionization. An experimental apparatus cooled to 100 K was used to reduce effects of blackbody radiation. Inhomogeneous, stray electric fields emanating from the surface of the waveguide have been characterized in frequency- and time-resolved measurements and coherence times of the Rydberg atoms on the order of 250 ns have been determined. These results represent a key element in the development of an experimental architecture to interface Rydberg atoms with solid-state devices.

Full spectrum millimeter-wave modulation

Abstract: In recent years, the development of new lithium niobate electro-optic modulator designs and material processing techniques have contributed to support the increasing need for faster optical networks by considerably extending the operational bandwidth of modulators. In an effort to provide higher bandwidths for future generations of networks, we have developed a lithium niobate electro-optic phase modulator based on a coplanar waveguide ridged structure that operates up to 300 GHz. By thinning the lithium niobate substrate down to less than 39 µm, we are able to eliminate substrate modes and observe optical sidebands over the full millimeter-wave spectrum.

RF Harmonic Distortion of CPW Lines on HR-Si and Trap-Rich HR-Si Substrates

Abstract: In this paper, the nonlinear behavior of coplanar waveguide (CPW) transmission lines fabricated on Si and high-resistivity (HR) Si substrates is thoroughly investigated. Simulations and experimental characterization of 50- Ω CPW lines are analyzed under small- and large-signal operation at 900 MHz for a wide variety of Si substrates with nominal resistivities from 10 Ω-cm up to values higher than 10 kΩ-cm. The introduction of a trap-rich layer to recover the Si substrate nominal HR characteristics is also considered. We experimentally demonstrate that the distortion level of a CPW line lying on Si substrate decreases with the effective resistivity sensed by the coplanar structure. Si substrates of effective resistivity higher than 3 kΩ-cm present harmonic levels below -80 dBm for an output power of +15 dBm.

Superconducting coplanar waveguide resonators for low temperature pulsed electron spin resonance spectroscopy

Abstract: We discuss the design and implementation of thin film superconducting coplanar waveguide micro- resonators for pulsed ESR experiments. The performance of the resonators with P doped Si epilayer samples is compared to waveguide resonators under equivalent conditions. The high achievable filling factor even for small sized samples and the relatively high Q-factor result in a sensitivity that is superior to that of conventional waveguide resonators, in particular to spins close to the sample surface. The peak microwave power is on the order of a few microwatts, which is compatible with measurements at ultra low temperatures. We also discuss the effect of the nonuniform microwave magnetic field on the Hahn echo power dependence.

Realization of a mesoscopic reprogrammable magnetic logic based on a nanoscale reconfigurable magnonic crystal

Abstract: We demonstrate functionality of magnetic logic based on a reconfigurable magnonic crystal in the form of a meander-type ferromagnetic nanowire. A ferromagnetic resonance method employing a microscopic coplanar waveguide has been used to detect the logic state of the structure coded in its magnetic ground state. Ferromagnetic resonance responses of anti-ferromagnetic and multi-cluster (mix of anti-ferromagnetic and ferromagnetic) ground states can be switched by applying a DC current in the signal line of the coplanar waveguide. Experimental demonstrations of device functionality as XOR and NOT logic gates are supported by the magnetic force microscopy images and micromagnetic simulations.

A Compact Wideband Microstrip Crossover

Abstract: In this letter, a planar microstrip crossover junction is presented. The conductor-backed coplanar waveguide (CB-CPW) structure with vias is employed as the core part of the crossover design. The dimensions of the CB-CPW crossover itself are 11.3 × 11.3 mm2. Two kinds of the transitions between the microstrip line (MSL) and the CB-CPW structure are merged into a double side print circuit board. This presented crossover junction has a bandwidth from 10 up to 6000 MHz for 20 dB return loss, 1 dB insertion loss and -20 dB isolation. Compared with the other designs, this planar crossover features wide bandwidth and compact configuration.

Etch Induced Microwave Losses in Titanium Nitride Superconducting Resonators

Abstract: We have investigated the correlation between the microwave loss and patterning method for coplanar waveguide titanium nitride resonators fabricated on Si wafers. Three different methods were investigated: fluorine- and chlorine-based reactive ion etches and an argon-ion mill. At high microwave probe powers the reactive etched resonators showed low internal loss, whereas the ion-milled samples showed dramatically higher loss. At single-photon powers we found that the fluorine-etched resonators exhibited substantially lower loss than the chlorine-etched ones. We interpret the results by use of numerically calculated filling factors and find that the silicon surface exhibits a higher loss when chlorine-etched than when fluorine-etched. We also find from microscopy that re-deposition of silicon onto the photoresist and side walls is the probable cause for the high loss observed for the ion-milled resonators

Ultra-Wideband Crossover Using Microstrip-to-Coplanar Waveguide Transitions

Abstract: The design of an ultra-wideband crossover for use in printed microwave circuits is presented. It employs a pair of broadside-coupled microstrip-to-coplanar waveguide (CPW) transitions, and a pair of uniplanar microstrip-to-CPW transitions. A lumped-element equivalent circuit is used to explain the operation of the proposed crossover. Its performance is evaluated via full-wave electromagnetic simulations and measurements. The designed device is constructed on a single substrate, and thus, it is fully compatible with microstrip-based microwave circuits. The crossover is shown to operate across the frequency band from 3.1 to 11 GHz with more than 15 dB of isolation, less than 1 dB of insertion loss, and less than 0.1 ns of deviation in the group delay.

Dual-Band Rhombus Slot Antenna Fed by CPW for WLAN Applications

Abstract: Design of a coplanar waveguide (CPW)-fed rhombus slot antenna for dual-band operation is proposed. With appropriate rhombic ring feeding structure and rectangular bulge components for impedance matching, the proposed antenna can provide two separate impedance bandwidths of 607 MHz (about 24.7% centered at 2.45 GHz) and 1451 MHz (about 26.3% centered at 5.5 GHz), which satisfies the WLAN operation in the 2.45-GHz band (about 3.4% bandwidth required) and 5.2/5.8-GHz bands (about 13% bandwidth required). Details of the constructed prototypes and experimental results are discussed.

Self-Packaged Millimeter-Wave Substrate Integrated Waveguide Filter With Asymmetric Frequency Response

Abstract: Substrate integrated waveguide (SIW) technology provides an effective solution for the low-cost and high-performance interconnect and packaging of microwave and millimeter wave systems. In this paper, Ka-band four-degree bandpass filters having asymmetric frequency response, which are required in the design of transmit and receive diplexers for high rejection between neighboring channels, are proposed and realized on an SIW platform. The filters are self-packaged due to the fact that a conductor-backed coplanar waveguide is used to directly excite the filters. Higher-order resonant mode is used to achieve the required negative coupling on the basis of a single-layer SIW. The proposed filters, having the same center frequency of 35 GHz and pass bandwidth of 1.3 GHz, are fabricated on a conventional Rogers RT/Duroid 6002 substrate with thickness of 0.508 mm by using a low-cost printed circuit board process. Measured results of those filters, which exhibit high single-sided selectivity and minimum in-band insertion loss of about 1.25 dB, agree well with simulated results.

Low-voltage, high-extinction-ratio, Mach-Zehnder silicon optical modulator for CMOS-compatible integration

Abstract: We demonstrate a carrier-depletion Mach-Zehnder silicon optical modulator, which is compatible with CMOS fabrication process and works well at a low driving voltage. This is achieved by the optimization of the coplanar waveguide electrode to reduce the electrical signal transmission loss. At the same time, the velocity and impedance matching are both considered. The 12.5 Gbit/s data transmission experiment of the fabricated device with a 2-mm-long phase shifter is performed. The driving voltages with the swing amplitudes of 1 V and 2 V and the reverse bias voltages of 0.5 V and 0.8 V are applied to the device, respectively. The corresponding extinction ratios are 7.67 and 12.79 dB.

A Robust UHF Near-Field RFID Reader Antenna

Abstract: A novel broadband antenna for ultrahigh-frequency (UHF) near-field radio frequency identification (RFID) applications is presented. The antenna is composed of a grounded coplanar waveguide (GCPW), a coplanar stripline (CPS), a lumped balun, multiple resistors, and a finite-sized ground plane. The load impedance is equal to the characteristic impedance of the CPS, hence traveling wave can transmit along the CPS. The proposed antenna structure can produce large currents along the CPS so that a strong and uniform magnetic field distribution is excited in the adjacent region around the antenna. The antenna geometry, design concept, simulated, and measured results are carefully discussed throughout the paper. Measurements show that the antenna operating with a commercial reader demonstrates good performance of tag identification with inductive coupling for near-field RFID applications. In addition, the parametric study is conducted to facilitate the design and optimization processes for engineers.

Internal loss of superconducting resonators induced by interacting two-level systems.

Abstract: In a number of recent experiments with microwave high quality superconducting coplanar waveguide resonators an anomalously weak power dependence of the quality factor has been observed. We argue that this observation implies that the monochromatic radiation does not saturate the two level systems (TLS) located at the interface oxide surfaces of the resonator and suggests the importance of their interactions. We estimate the microwave loss due to interacting TLS and show that the interactions between TLS lead to a drift of their energies that result in a much slower, logarithmic dependence of their absorption on the radiation power in agreement with the data.

Asymmetric Coplanar Waveguide (ACPW) Zeroth-Order Resonant (ZOR) Antenna With High Efficiency and Bandwidth Enhancement

Abstract: A novel low-profile zeroth-order (ZOR) antenna is presented. The feature of ZOR based on periodic structures is employed to reduce the antenna size, while these antennas generally suffer from narrow bandwidth. A single-layer asymmetric coplanar waveguide (ACPW) structure is proposed to realize a bandwidth-extended ZOR antenna, where the antenna bandwidth is characterized by an equivalent circuit model. The ACPW structure not only provides the design freedom, but also overcomes the design constraint of the traditional CPW. The ACPW ZOR antenna is verified by both full-wave simulations and experiments. As an advantage of the proposed method, the size of antenna is reduced, and the resonant frequency of zeroth-order mode is 1.94 GHz with radiation efficiency of 85%, measured 10-dB fractional bandwidth up to 10.3%, and omnidirectional peak gain of 2.3 dBi.

220-GHz Solid-State Power Amplifier Modules

Abstract: This paper reports on several solid-state power amplifier (PA) modules operating at frequencies around the 220-GHz propagation window. Included is a single module demonstrating saturated output power ≥60 mW from 205 to 225 GHz and peak output power of 75 mW at 210 GHz using eight-way on-chip power combining. The output power is further increased by using waveguide power combining with WR-4 waveguide. Results include a single two-way combined module achieving >; 100 mW of power from 210 to 225 GHz and four-way combining using two two-way combiners to reach 185 mW of output power at 210 GHz. The amplifier MMICs uses sub-50-nm InP HEMT transistors, coplanar waveguide (CPW) technology, and on-chip electromagnetic transitions to waveguide. Finally, preliminary burn-in and initial room-temperature lifetest data is shown.

Compact CPW-fed planar monopole antenna with distinct triple bands for WiFi/WiMAX applications

Abstract: A compact coplanar waveguide (CPW)-fed planar monopole antenna with triple band operation is presented. By inserting two I-shaped notched slots and a open-ended U-shaped slot on the edge of the radiation patch, and integrating two symmetrical meander microstrip-lines on the upper edge of two rectangular ground planes, three operating bands covering 2.4-2.63, 3.23-3.8 and 5.15-5.98-GHz can be achieved. Moreover, the designed antenna, with compact size of 23-30-mm 2 , can provide excellent characteristics, including better performance of interference suppression, nearly dipole-like radiation pattern and moderate gain for three bands, which prove that the proposed antenna is very suitable for WiFi/WiMAX applications.

Monopole-based rectenna for microwave energy harvesting of uhf rfid systems

Abstract: This paper presents a rectifying antenna (rectenna) for the harvesting of the microwave energy associated to UHF (Ultra- High Frequency) Radio Frequency IDentiflcation (RFID) systems. The proposed device uses a capacitively loaded T-shaped monopole with a coplanar waveguide feeding line as receiving antenna and a flve-stage voltage multiplier as rectifler. Experimental results demonstrating an RF-to-DC conversion e-ciency of about 54% with an input power density of 80"W/cm 2 will be presented and discussed.

A Millimeter-Wave Gain Enhanced Multi-Beam Antenna Based on a Coplanar Cylindrical Dielectric Lens

Abstract: A planar millimeter-wave high gain multi-beam antenna with 5 beams in azimuth based on substrate integrated waveguide (SIW) fed antipodal linear tapered slot antennas (ALTSAs) and a coplanar cylindrical dielectric lens is proposed and implemented at 28 GHz. Both the antennas and the lens are fabricated on a single planar substrate covered by high permittivity substrate with a radius of 0.5λ0 . A prototype with 5 beams has been designed, fabricated and measured. The measured gain of each beam is around 20 dB which is about 6.5 dB higher than that of the ALTSA element. The gain enhanced multi-beam lens antenna is with the advantages of high gain, good beam uniformity, higher isolation between ports, low cost, and easily be integrated with other coplanar circuits etc.