Showing papers on "Coplanar waveguide published in 2007"

Noise properties of superconducting coplanar waveguide microwave resonators

Abstract: The authors have measured noise in thin-film superconducting coplanar waveguide resonators. This noise appears entirely as phase noise, equivalent to a jitter of the resonance frequency. In contrast, amplitude fluctuations are not observed at the sensitivity of their measurement. The ratio between the noise power in the phase and amplitude directions is large, in excess of 30 dB. These results have important implications for resonant readouts of various devices such as detectors, amplifiers, and qubits. They suggest that the phase noise is due to two-level systems in dielectric materials.

Frequency Tunable Microstrip Patch Antenna Using RF MEMS Technology

Abstract: A novel reconfigurable microstrip patch antenna is presented that is monolithically integrated with RF microelectromechanical systems (MEMS) capacitors for tuning the resonant frequency. Reconfigurability of the operating frequency of the microstrip patch antenna is achieved by loading it with a coplanar waveguide (CPW) stub on which variable MEMS capacitors are placed periodically. MEMS capacitors are implemented with surface micromachining technology, where a 1-mum thick aluminum structural layer is placed on a glass substrate with a capacitive gap of 1.5 mum. MEMS capacitors are electrostatically actuated with a low tuning voltage in the range of 0-11.9 V. The antenna resonant frequency can continuously be shifted from 16.05 GHz down to 15.75 GHz as the actuation voltage is increased from 0 to 11.9 V. These measurement results are in good agreement with the simulation results obtained with Ansoft HFSS. The radiation pattern is not affected from the bias voltage. This is the first monolithic frequency tunable microstrip patch antenna where a CPW stub loaded with MEMS capacitors is used as a variable load operating at low dc voltages

Apparatus for transitioning millimeter wave between dielectric waveguide and transmission line

Abstract: Provided is an apparatus for transitioning a millimeter wave between dielectric waveguide and transmission line using a millimeter wave transition structure formed by the dielectric waveguide, the transmission line, and a slot to transition a signal with lower losses. The apparatus includes: transmission lines disposed respectively at input and output terminals on an uppermost dielectric substrate in a signal transition direction and adapted to transition a signal; a dielectric waveguide formed by a via array disposed between top and bottom ground surfaces of a lowermost dielectric substrate in the signal transition direction as a signal transition path; and slots disposed at a signal transition path of an upper ground surface of each dielectric substrate to connect the transmission lines to the dielectric waveguide so as to transition a signal from the transmission line of the input terminal to the transmission line of the output terminal through the dielectric waveguide.

Novel Dual-Mode Dual-Band Filters Using Coplanar-Waveguide-Fed Ring Resonators

Abstract: This paper presents a novel approach for designing dual-mode dual-band bandpass filters with independently controlled center frequencies and bandwidths. Two microstrip perturbed ring resonators are employed to obtain dual-mode dual-band responses. Novel feeding structures are introduced to simultaneously feed the ring resonators and conveniently control the coupling strength between resonators and feeding lines, resulting in a wide tunable range of external quality factors. Two kinds of filter configurations with compact size are proposed. Both of them provide sufficient degrees of freedom to satisfy various requirements of external qualify factors and coupling coefficients at both passbands. Therefore, the center frequencies and fractional bandwidths of both passbands can be independently tuned to desired specifications within a wide range. To verify the proposed method, four filters are implemented. The measured results exhibit dual-mode dual-band bandpass responses with high selectivity.

Vector network analyzer ferromagnetic resonance of thin films on coplanar waveguides: Comparison of different evaluation methods

Abstract: We have carried out two-port network analyzer ferromagnetic resonance measurements on a coplanar waveguide. We present a detailed description on how to calculate from the raw measurement data a value proportional to the complex susceptibility and permittivity of the ferromagnetic material. Necessary corrections for errors due to imprecise sample placement on the waveguide and the sample dimensions are presented. Evaluated data up to 15 GHz are provided for two model samples: a 40 nm Co80Fe20 layer showing a large linewidth (≈900 MHz) and a 40 nm Co72Fe18B10 layer yielding a small linewidth (≈360 MHz). Using these experimental data the presented evaluation scheme based on all four scattering parameters is then compared to commonly used approximate evaluation schemes relying on only one S parameter. These approximate methods show close agreement for the ferromagnetic resonance frequencies (the relative error is below 1%). However, the resonance linewidths show a relative error that can reach 10% in comparis...

Compact Ultra-Wideband Microstrip/Coplanar Waveguide Bandpass Filter

Abstract: A novel ultra wideband (UWB) bandpass filter is presented, using a compact coupled microstrip/coplanar waveguide (CPW) structure. The filter comprises of a single CPW quarter-wavelength resonator which is coupled to two microstrip open-circuited stubs on the other side of a common substrate. The two microstrip open-circuited stubs, which are about a quarter-wavelength long at the center frequency, can function as two resonators with associated coupling arrangement to the CPW. This forms a very compact three-pole filter. The proposed filter also exhibits a quasi-elliptic function response, with one finite-frequency transmission zero closer to each side of the passband. Thus, a high selectivity is achieved using a small number of resonators, which leads to low insertion loss and group delay across the passband. The performance is predicated using EM simulations and verified experimentally. The experimental filter shows a fractional bandwidth of 90% at a center frequency of 6.4GHz, with two observable transmission zeros (attenuation poles) at 1.95 and 10.36GHz, respectively. Furthermore, it has a very small size only amounting to 0.25 by 0.08 guided wavelength at the center frequency

Nonlinearities and parametric amplification in superconducting coplanar waveguide resonators

Abstract: Experimental investigations of the nonlinear properties of superconducting niobium coplanar waveguide resonators are reported. The nonlinearity due to a current dependent kinetic inductance of the center conductor is strong enough to realize bifurcation of the nonlinear oscillator. When driven with two frequencies near the threshold for bifurcation, parametric amplification with a gain of +22.4dB is observed.

Tunable resonators for quantum circuits

Abstract: We have designed, fabricated and measured high-Q $\lambda/2$ coplanar waveguide microwave resonators whose resonance frequency is made tunable with magnetic field by inserting a DC-SQUID array (including 1 or 7 SQUIDs) inside. Their tunability range is 30% of the zero field frequency. Their quality factor reaches up to 3$\times10^4$. We present a model based on thermal fluctuations that accounts for the dependance of the quality factor with magnetic field.

Microwave-assisted magnetization switching of Ni80Fe20 in magnetic tunnel junctions

Abstract: Microwave-assisted magnetization switching was investigated using Fe30Co70∕AlOx∕Ni80Fe20 magnetic tunnel junctions incorporated with a coplanar waveguide. Coercivity field of Ni80Fe20 layer was dramatically reduced in a small amplitude microwave. The authors eliminated the thermal effect in coercivity reduction by comparing two types of measurements which are with and without spin precession in the presence of microwave. It was found that the coercivity reduction depends on both frequency and power of the microwave. The numerical simulation based on Landau-Lifshitz-Gilbert equation reproduced the trend of the experimental data. The results indicate that microwave can be an efficient means to switch the magnetization of a thin film.

Surface Micromachined Microelectromechancial Ohmic Series Switch Using Thin-Film Piezoelectric Actuators

Abstract: This paper presents results on a surface micromachined RF microelectromechanical switch that uses piezoelectric actuators. The switch uses solution chemistry-derived lead zirconate titanate thin films spun deposited onto a high-resistivity silicon substrate with coplanar waveguide transmission lines. Actuation voltages, applied via circuits independent of the RF circuitry, average less than 10 V, with switch operation demonstrated as low as 2 V. The series switch exhibits better than 20-dB isolation from dc up to 65 GHz and as large as 70 dB below 1 GHz. In the closed state, the switch has an insertion loss less than 1 dB up to 40 GHz, limited in this demonstration by substrate losses from the elastic layer used to stress control the piezoelectric actuators. Switching speeds for the different designs are in the range of 40-60 ms. Thermal sensitivity measurements show no change in isolation observed for temperatures up to 125degC. However, an increase in actuation voltage is required at elevated temperatures.

Entangling a nanomechanical resonator and a superconducting microwave cavity

Abstract: We propose a scheme able to entangle at the steady state a nanomechanical resonator with a microwave cavity mode of a driven superconducting coplanar waveguide. The nanomechanical resonator is capacitively coupled with the central conductor of the waveguide and stationary entanglement is achievable up to temperatures of tens of milliKelvin.

Microwave dielectric heating of fluids in an integrated microfluidic device

Abstract: The ability to selectively and precisely control the temperature of fluid volumes ranging from a few microliters to sub-nanoliters in microfluidic networks is vital for a wide range of applications in micro total analysis systems (μTAS). In this work, we characterize and model the performance of a thin film microwave transmission line integrated with a microfluidic channel to heat fluids with relevant buffer salt concentrations over a wide range of frequencies. A microchannel fabricated in poly(dimethylsiloxane) (PDMS) is aligned with a thin film microwave transmission line in a coplanar waveguide (CPW) configuration. The electromagnetic fields localized in the gap between the signal and ground lines of the transmission line dielectrically heat the fluid in the selected region of the microchannel. Microwave S-parameter measurements and optical fluorescence-based temperature measurements are used with a theoretical model developed based on classical microwave absorption theory to fully characterize the temperature rise of the fluid. We observe a 0.95 °C mW−1 temperature rise at 15 GHz and confirm that the temperature rise of the fluid is predominantly due to microwave dielectric heating.

Tunable stop-band filter at Q-band based on RF-MEMS metamaterials

Abstract: Presented for the first time is a metamaterial transmission line that combines complementary split ring resonators (CSRRs) and RF microelectromechanical systems (RF-MEMS). The device consists on a coplanar waveguide structure loaded in its central strip with CSRRs embedding RF-MEMS variable capacitors. Owing to the presence of the CSRRs, the structure behaves as a stop-band filter. Through the actuation of the electrostatic RF-MEMS devices, the electrical characteristics of the CSRRs are modified so that their resonance frequency, and as a result the central frequency of the stop-band filter, can be tuned. This is the first time that an RF-MEMS tunable metamaterial-based filter has been designed for operation at Q-band.

A Broadband Compact Microstrip Rat-Race Hybrid Using a Novel CPW Inverter

Abstract: A new compact microstrip rat-race hybrid with an octave bandwidth employing a novel frequency-independent coplanar waveguide (CPW) phase inverter is reported in this paper. The 270deg branch of a conventional rat-race is replaced by a -90deg branch, which is realized by a 90deg microstrip line and the CPW phase inverter. A new microstrip-to-CPW transition is introduced for which a lumped-element model is devised to facilitate parameter optimization. The designed transition has an insertion loss less than 0.33 dB across the designed frequency band from 1.5 to 3.5 GHz. The footprint of the proposed design is reduced by 75% and shows almost 60% and 80% enhancements in the 0.5-dB mismatch bandwidth of amplitude and 10deg mismatch bandwidth of phase, respectively, when compared with the conventional implementation. The proposed hybrid can be fabricated using a conventional printed-circuit and plated thru-hole technologies

Demonstration of Sub-Millimeter Wave Fundamental Oscillators Using 35-nm InP HEMT Technology

Abstract: In this letter, 254-, 314-, and 346-GHz fundamental oscillators are demonstrated. These are the highest frequency oscillators using three-terminal devices reported to date. The performance is enabled through a 35-nm InP HEMT process with maximum frequency of oscillation (fmax) of 600GHz. These first-pass designs use coplanar waveguide (CPW) technology and include on-chip resonator and output matching. The maximum available gain (MAG) of these devices has been measured to be ~9.6dB at 200GHz

Niobium and Tantalum High Q Resonators for Photon Detectors

Abstract: We have measured the quality factors and phase noise of niobium and tantalum coplanar waveguide microwave resonators on silicon. The results of both materials are similar. We reach quality factors up to 105. At low temperatures the quality factors show an anomalous increase, while the resonance frequency remains constant for increasing power levels. The resonance frequency starts to decrease at temperatures around a tenth of the critical temperature. The phase noise exhibits a 1/f like slope. We attribute this behavior to the silicon dielectric.

Broadband Electrical Characterization of Multiwalled Carbon Nanotubes and Contacts

Abstract: The electrical response of an individual multiwalled carbon nanotube (MWNT) and its contacts, welded to a coplanar waveguide (CPW), was measured up to 24 GHz using a technique that removes environment effects. This is the first time MWNT contact effects have been systematically isolated from the CPW. Each contact response was quite different and also showed a pronounced sensitivity to ambient light. Adding more contact material clearly changed the high-frequency electrical response and the sensitivity to light.

CPW-FED Notched Monopole Antenna for Umts/imt-2000/WLAN Applications

Abstract: A single-layer coplanar waveguide (CPW)-fed planar monopole antenna consisting of a rectangular microstrip patch with double-cornered notches to obtain dual wideband operations covering UMTS/IMT-2000 and 5.2/5.8 GHz WLAN bands is presented. Prototypes of the proposed antenna have been constructed and experimentally studied. The measured results explore good radiation characteristics of monopole-like patterns, 19.1 and 53.5% impedance bandwidths, and 3.2and 6.5 dBi peak antenna gains for the lower and upper frequency bands, respectively. Details of the proposed design and experimental results are presented and discussed.

Study of equivalent circuits for open-ring and split-ring resonators in coplanar waveguide technology

Abstract: A study of open-ring resonators and split-ring resonators is performed in terms of equivalent circuits. The resonant particles can be intrinsically described by simple LC circuits; even if their resonant behaviours are caused by conceptually different phenomena, either distributed or quasi-static resonances can be attributed for designs with similar geometrical dimensions. When inserted on the back-plane of a coplanar waveguide, and combined with short-circuiting wires on the top-plane, the periodic structures designed so far exhibit a certain pass-band where backward waves are generated. The left-handed behaviour is proved through the analysis of the phase of different length transmission lines and can be observed for both types of resonators. Full-wave simulations and experimental results performed on manufactured prototypes validate the overall good performance of the proposed equivalent circuits. Detailed models for the different elements of the unit-cells are provided on the basis of different analytical approaches.

Antenna Array Feed Line Structures For Millimeter Wave Applications

Abstract: Improved feed line networks for antenna arrays operating at millimeter wave frequencies are provided for constructing planar antenna arrays printed on the surface of a dielectric substrate. A planar antenna array includes an array of planar radiator elements interconnected through a feed line network of planar coplanar transmission lines that enable high-efficiency operation, at millimeter wave operating frequencies. For example, a feed network may be formed with a network of coplanar strip line transmission lines including one or more coplanar strip line (CPS) and one or more coplanar waveguide (CPW) transmission line, which are interconnected using balun structures, to enable high efficiency operation at millimeter wave frequencies.

A coplanar waveguide fed monopole ultra-wideband antenna having band-notched frequency function by two folded-striplines

Abstract: A compact coplanar waveguide fed monopole ultra-wideband antenna having a frequency-notch function is proposed. The notched frequency band can be achieved by including the two L-shape striplines in the bottom of the substrate. The designed antenna has a notch band of 5.10–6.25 GHz while 10 dB return loss is ranged from 3.04 to 12.0 GHz. The measured return loss, radiation patterns, and gains are presented. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2747–2750, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22852

Integrated terahertz TEM horn antenna

Abstract: A terahertz transverse electromagnetic horn antenna (THz-TEMHA) monolithically integrated on a gallium arsenide substrate has been studied by means of subpicosecond pulses generated and measured on a 50 Omega coplanar waveguide. The measured reflection coefficient is below -10 dB from 100 GHz to about 1 THz. A terahertz ranging experiment was carried out in a monostatic configuration

Non-Toxic Liquid-Metal 2-100 GHz MEMS Switch

Abstract: In this paper, the first wide-band MEMS capacitive switch using non-toxic liquid metal, Galinstan, is reported. Controlled movement of Galinstan in a micro-channel alters the impedance of a coplanar waveguide (CPW) line from 50 Omega (off-state) to an effective RF short circuit (on-state). The RF short circuit in particular is achieved when a slug of Galinstan capacitively connects the center conductor with the ground planes of the CPW line. Galinstan is reliably manipulated by surrounding it with Teflon solution. Because of Teflon, no residual liquid metal is observed when Galinstan moves. In addition, the Teflon solution has insignificant RF loss and therefore does not adversely affect the switch loss in its off-state even up to 100 GHz. The insertion loss of the switch is measured at 0.2, 0.7 and 1.3 dB at 20, 40 and 100 GHz respectively and is mainly due to the 1500 mum long transmission line. The on-state shunt capacitance is measured to be 4 pF which results in an on-state isolation of greater than 20 dB from 20 to 100 GHz.

Multi-metal coplanar waveguide

Abstract: A coplanar waveguide CPW using multi-layer interconnection CMOS technology is provided. In the CPW including an interlayer insulator disposed on a substrate, metal multilayers disposed on the interlayer insulator, and a ground line-a signal line-a ground line formed of an uppermost metal layer, when a ground line of a lowermost layer is connected to the ground line of the uppermost layer, intermediate metal layers are designed to gradually increase or decrease in width, or to be uneven so as to maximize an area where an ultra-high frequency spreads, thereby minimizing CPW loss and maximizing a slow wave effect. As a result, it is possible to improve performance of an ultra-high frequency circuit and miniaturize the circuit.

Millimeter-wave wideband transition from CPW to substrate integrated waveguide on electrically thick high-permittivity substrates

Abstract: A wideband transition from coplanar waveguide (CPW) to substrate integrated waveguide (SIW) is proposed and presented in the 50 GHz frequency range. Electrically thick alumina was used in this case, representative for other high-permittivity substrates such as semiconductors. Simulations predict less than -15 dB return loss within a 35 % bandwidth. CPW probe measurements were carried out and 40 % bandwidth were achieved at -0.5 dB insertion loss for a single transition. Modified SIW via configurations being suitable for simplified fabrication on electrically thick substrates in the upper millimeter-wave spectrum are discussed in the second part.

Ultra-wideband CPW-fed antenna with round corner rectangular slot and partial circular patch

Abstract: A novel coplanar waveguide (CPW)-fed ultra-wideband wide slot antenna is proposed. Because of the round corner of the rectangular slot and partial circular patch, the bandwidth of the antenna is enhanced largely. Good agreement between the measurement and simulation has been achieved. The results show that the impedance bandwidth of the antenna reaches up to 4.5–15.5 GHz for S11<−15 dB and 2.5–18 GHz for S11<−10 dB. Meanwhile, a good omni-directional radiation performance has also been achieved.

Novel Design of UWB Antenna with Band - Notch Capability

Abstract: An ultra-wideband (UWB) antenna with a narrow frequency notch is presented. The antenna has been fabricated on a Duroid 5870 substrate and occupies an area of only 30times35 mm2. Starting from a trapezoidal planar patch exhibiting a VSWR smaller than 2.5 in the 3.5-10 GHz band, a frequency notch at 5.65 GHz is introduced by two slots near the coplanar waveguide feeding the patch. The measured return loss shows a good agreement with the simulation results and proves that this kind of antenna is suitable for reducing the detrimental interference effects of WLAN, operating around 5.5 GHz, on UWB radio links.

A Novel 3-dB Directional Coupler With Broad Bandwidth and Compact Size Using Composite Right/Left-Handed Coplanar Waveguides

Abstract: A wideband composite right/left-handed (CRLH) coplanar waveguide (CPW) coupler with 3-dB coupling value and quadrature phase difference is presented. Compared with the conventional edge-coupled CPW coupler, this symmetrical structure, consisting of a gap capacitor, a broadside-coupled capacitor, and a meandering short-circuited stub inductor, achieves wider operating bandwidth and larger coupling level. The 3-dB CRLH CPW coupler with 0.7mm spacing between coupled lines exhibits an amplitude balance of 2dB and a phase balance of 900 plusmn 50 from 3.2 to 7.6GHz. The coupled-line length and the port impedance of the proposed structure are approximately lambda/4 and 50Omega, respectively, which makes it more compact than the cascaded CRLH microstrip coupled-line coupler. To characterize this structure, the equivalent circuit model including the unique coupling mechanism within CRLH CPWs is established and verified by measurement. The signal with less dispersion on output ports is demonstrated based on the standard deviation of group delay time

Broadband Permittivity of Liquids Extracted from Transmission Line Measurements of Microfluidic Channels

Abstract: We present a semi-analytical procedure to extract the permittivity of fluids from measurements in our microfluidic-microelectronic platform. This platform consists of broadband coplanar waveguide transmission lines with integrated microfluidic channels for characterizing the dielectric properties of submicroliter fluid samples. On-wafer calibration techniques are used to obtain the S-parameters of the composite structure (transmission line and microfluid channel) up to 40 GHz. Using microwave network analysis theory, we isolated the response of the microfluidic channel. We modeled the microfluidic channel as a distributed transmission line segment and as a single RLCG elemental segment. Both approaches analytically yield the circuit capacitance CF and conductance GF per unit length of the segment incorporating the microfluidic channel. A finite element electromagnetic simulator is then used to obtain the permittivity of the fluid as a continuous function of frequency. We applied this technique to extract the permittivity of submicroliter liquid volumes. Here we present results on polystyrene latex beads suspended in an aqueous solution over the frequency range from 100 MHz to 40 GHz.

Waveguide to microstrip line coupling apparatus

Abstract: Electrical coupling apparatus providing transition between a high radio frequency waveguide and a perpendicularly oriented microstrip line without use of a shorting cap fixes an open end of the waveguide perpendicularly to a dielectric substrate. The microstrip line is carried on the substrate and couples through a hole in the waveguide wall to a microstrip patch on the substrate within the waveguide having a resonance with the waveguide encompassing a predetermined high radio frequency bandwidth of signals to be conducted by the apparatus. A plurality of parallel conducting members form a via fence aligned with the waveguide wall and extending through the substrate to electrically connect the waveguide to a planar ground conductor that covers the opposite side of the substrate, including the area under the open end of the waveguide.