Showing papers on "Coplanar waveguide published in 2008"
TL;DR: In this article, the temperature-dependent frequency shift of five niobium superconducting coplanar waveguide microresonators with center strip widths ranging from 3 to 50 µm was measured at temperatures in the range of 100-800 mK, far below the 9.2 K transition temperature of niibium.
Abstract: We present measurements of the temperature-dependent frequency shift of five niobium superconducting coplanar waveguide microresonators with center strip widths ranging from 3 to 50 µm, taken at temperatures in the range of 100–800 mK, far below the 9.2 K transition temperature of niobium. These data agree well with the two-level system (TLS) theory. Fits to this theory provide information on the number of TLSs that interact with each resonator geometry. The geometrical scaling indicates a surface distribution of TLSs and the data are consistent with a TLS surface layer thickness of the order of a few nanometers, as might be expected for a native oxide layer.
373 citations
TL;DR: In this paper, the physical properties of coplanar waveguide resonators and their relation to the materials properties for use in circuit quantum electrodynamics (QED) were analyzed.
Abstract: High quality on-chip microwave resonators have recently found prominent new applications in quantum optics and quantum information processing experiments with superconducting electronic circuits, a field now known as circuit quantum electrodynamics (QED). They are also used as single photon detectors and parametric amplifiers. Here we analyze the physical properties of coplanar waveguide resonators and their relation to the materials properties for use in circuit QED. We have designed and fabricated resonators with fundamental frequencies from 2 to 9 GHz and quality factors ranging from a few hundreds to a several hundred thousands controlled by appropriately designed input and output coupling capacitors. The microwave transmission spectra measured at temperatures of 20 mK are shown to be in good agreement with theoretical lumped element and distributed element transmission matrix models. In particular, the experimentally determined resonance frequencies, quality factors, and insertion losses are fully and consistently explained by the two models for all measured devices. The high level of control and flexibility in design renders these resonators ideal for storing and manipulating quantum electromagnetic fields in integrated superconducting electronic circuits.
352 citations
TL;DR: In this article, the authors present the loss tangents of some common amorphous and crystalline dielectrics, measured at low temperatures (T < 100mK) with near single-photon excitation energies, using both coplanar waveguide and lumped LC resonators.
Abstract: The microwave performance of amorphous dielectric materials at very low temperatures and very low excitation strengths displays significant excess loss. Here, we present the loss tangents of some common amorphous and crystalline dielectrics, measured at low temperatures (T<100mK) with near single-photon excitation energies, E∕ℏω0∼1, using both coplanar waveguide and lumped LC resonators. The loss can be understood using a two-level state defect model. A circuit analysis of the half-wavelength resonators we used is outlined, and the energy dissipation of such a resonator on a multilayered dielectric substrate is theoretically considered.
329 citations
TL;DR: In this article, the temperature-dependent frequency shift of five niobium superconducting coplanar waveguide microresonators with center strip widths ranging from 3 $\mu$m to 50 $m, taken at temperatures in the range 100-800 mK, far below the 9.2 K transition temperature of Niobium.
Abstract: We present measurements of the temperature-dependent frequency shift of five niobium superconducting coplanar waveguide microresonators with center strip widths ranging from 3 $\mu$m to 50 $\mu$m, taken at temperatures in the range 100-800 mK, far below the 9.2 K transition temperature of niobium. These data agree well with the two-level system (TLS) theory. Fits to this theory provide information on the number of TLS that interact with each resonator geometry. The geometrical scaling indicates a surface distribution of TLS, and the data are consistent with a TLS surface layer thickness of order a few nm, as might be expected for a native oxide layer.
275 citations
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
TL;DR: In this paper, the authors present measurements of the low-temperature excess frequency noise of four niobium superconducting coplanar waveguide microresonators, with center strip widths ranging from 3 to 20 µm.
Abstract: We present measurements of the low-temperature excess frequency noise of four niobium superconducting coplanar waveguide microresonators, with center strip widths sr ranging from 3 to 20 µm. For a fixed internal power, we find that the frequency noise decreases rapidly with increasing center strip width, scaling as 1/s r 1.6 . We show that this geometrical scaling is readily explained by a simple semiempirical model which assumes a surface distribution of independent two-level system fluctuators. These results allow the resonator geometry to be optimized for minimum noise.
196 citations
TL;DR: In this article, a new wideband circularly polarized square slot antenna (CPSSA) with a coplanar waveguide (CPW) feed was proposed, which features two inverted-L grounded strips around two opposite corners of the slot and a widened tuning stub protruded into the slot from the signal strip of the CPW.
Abstract: This paper presents a new wideband circularly polarized square slot antenna (CPSSA) with a coplanar waveguide (CPW) feed. The proposed antenna features two inverted-L grounded strips around two opposite corners of the slot and a widened tuning stub protruded into the slot from the signal strip of the CPW. Broadside circular-polarization (CP) radiation can be easily obtained using a simple design procedure. For the optimized antenna prototype, the measured bandwidth with an axial ratio (AR) of less than 3 dB is larger than 25% and the measured VSWR les 2 impedance bandwidth is as large as 52%.
185 citations
TL;DR: In this article, the authors present measurements of the low-temperature excess frequency noise of four niobium superconducting coplanar waveguide microresonators, with center strip widths $s_r$ ranging from 3 $m to 20 $m.
Abstract: We present measurements of the low--temperature excess frequency noise of four niobium superconducting coplanar waveguide microresonators, with center strip widths $s_r$ ranging from 3 $\mu$m to 20 $\mu$m. For a fixed internal power, we find that the frequency noise decreases rapidly with increasing center strip width, scaling as $1/s_r^{1.6}$. We show that this geometrical scaling is readily explained by a simple semi-empirical model which assumes a surface distribution of independent two-level system fluctuators. These results allow the resonator geometry to be optimized for minimum noise.
142 citations
DSM1
TL;DR: In this paper, a high-Q λ/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 was designed.
Abstract: We have designed, fabricated and measured high-Q λ/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 3×104. We present a model based on thermal fluctuations that accounts for the dependence of the quality factor with magnetic field.
136 citations
TL;DR: In this article, an ultra-wideband (UWB) U type monopole antenna fed by a coplanar waveguide (CPW) is proposed, which has low profile and very compact size (14.48 mm × 28.74 mm × 0.8 mm).
Abstract: An ultra-wideband (UWB) U type monopole antenna fed by a coplanar waveguide (CPW) is proposed. It has low profile and very compact size (14.48 mm × 28.74 mm × 0.8 mm). It provides an wide impedance bandwidth ranging from 3.08 GHz to about 12.75 GHz adjustable by variation of its parameters, such as the relative permittivity and thickness of the substrate, width, and feed and ground plane dimensions. Parametric study is presented. Details of the proposed ultra-wideband design are described. Simulation results are presented and discussed in this paper.
120 citations
01 Feb 2008
TL;DR: In this article, a coplanar waveguide structure on various substrates at 900 MHz was measured and significant distortion for silicon substrates was demonstrated for the first time, and the contribution of the silicon substrate to high harmonic levels was investigated experimentally, and an efficient technological solution based on the introduction of a traprich layer was demonstrated.
Abstract: Harmonic distortion (HD) is measured arising from coplanar waveguide structures on various substrates at 900 MHz, and significant distortion for silicon substrates is demonstrated for the first time. For an input power of +35 dBm, 2nd harmonic power of -47 dBm and 3rd of -57 dBm are measured for a thru calibration structure on oxidized high-resistivity silicon (HRS) substrates, and 2nd harmonic of -23 and 3rd of -20 dBm for a longer line on a thinner oxide. These levels are high compared to a full cellular transmit switch product specification of -45 and -40 dBm for 2nd and 3rd harmonics, respectively, at similar power levels. The contribution of the silicon substrate to high harmonic levels is investigated experimentally, and an efficient technological solution based on the introduction of a trap-rich layer is demonstrated.
TL;DR: In this article, a broadband circularly-polarized (CP) square slot antenna fed by an asymmetric coplanar waveguide (CPW) from a corner of the slot is proposed.
Abstract: A novel broadband circularly-polarised (CP) square slot antenna fed by an asymmetric coplanar waveguide (CPW) from a corner of the slot is proposed. A CP bandwidth larger than 10% can be attained simply by using an inverted-L tuning stub protruded from the signal line of the CPW. With an additional pair of grounded strips implanted in the slot, the 3 dB axial-ratio bandwidth and the VSWR les 2 impedance bandwidth can be greatly raised to be as high as 30 and 35%, respectively.
TL;DR: In this paper, a superconducting flux qubit strongly coupled to a single mode of a high-quality transmission-type coplanar-waveguide resonator was experimentally studied and the qubit-resonator coupling was revealed in the resonator transmission spectrum as a vacuum Rabi splitting.
Abstract: We have experimentally studied a superconducting flux qubit strongly coupled to a single mode of a high-quality transmission-type coplanar-waveguide resonator. The qubit-resonator coupling is revealed in the resonator transmission spectrum as a vacuum Rabi splitting. In the dispersive regime the qubit energy levels are spectroscopically probed. We observe a shift in the qubit transition frequency that linearly depends on the number of photons in the resonator, which is attributed to the ac-Zeeman shift. The observations are in agreement with the theoretical predictions.
TL;DR: It is shown that pairs of atoms optically excited to the Rydberg states can strongly interact with each other via effective long-range dipole-dipole or van der Waals interactions mediated by their nonresonant coupling to a common microwave field mode of a superconducting coplanar waveguide cavity.
Abstract: We show that pairs of atoms optically excited to the Rydberg states can strongly interact with each other via effective long-range dipole-dipole or van der Waals interactions mediated by their nonresonant coupling to a common microwave field mode of a superconducting coplanar waveguide cavity. These cavity mediated interactions can be employed to generate single photons and to realize in a scalable configuration a universal phase gate between pairs of single photon pulses propagating or stored in atomic ensembles in the regime of electromagnetically induced transparency.
TL;DR: In this article, the authors describe the design and manufacturing process of new stretchable high-frequency interconnects with meander-shaped conductors in a coplanar waveguide topology.
Abstract: The increasing number of biomedical applications for electronic systems have led to the need for stretchable electronics in order to significantly enhance the comfort of the user. This paper describes the design and manufacturing process of new stretchable high-frequency interconnects with meander-shaped conductors in a coplanar waveguide topology. The novel interconnects are produced based on laser-ablation of a copper foil, which is then embedded in a highly stretchable bio-compatible silicone material. Measurements on prototypes of the designed stretchable high-frequency interconnects revealed a maximal magnitude of -14 dB for the reflection coefficient and a minimal magnitude of -4 dB for the transmission coefficient in the frequency band up to 3 GHz. The influence of stretch on the performance of the high-frequency interconnects was analyzed using a stretch testing machine. The results showed that nor the magnitude, neither the phase of the transmission coefficient was influenced by elongations up to 20%.
TL;DR: In this article, the authors presented a radical departure from the standard RF microelectromechanical systems (MEMS) devices and introduced novel miniature MEMS switched capacitors for RF to millimeter-wave applications, which are around 150 times smaller in lateral dimensions than standard MEMS designs.
Abstract: This paper presents a radical departure from the standard RF microelectromechanical systems (MEMS) devices and introduces novel miniature MEMS switched capacitors for RF to millimeter-wave applications, which are around 150 times smaller in lateral dimensions than standard MEMS designs. The measured capacitance of a single device (l,w,t of 20, 9.5, 0.37 mum), suspended 0.25 mum above the pull-down electrode, is 3.9 and 11.7-12.1 iF (Cr = 3.0-3.1) in the up- and down-state positions, respectively. The measured capacitance ratio of a 4 X 4 array fabricated on quartz substrates and in a coplanar waveguide (CPW) configuration is 3.0 with an electrical Q > 90 at 20 GHz. The miniature MEMS spring constant is very high, and is much less sensitive to residual stress or temperature variations than standard MEMS devices. Dielectric charging simulations show that these devices can withstand a charge density 6.25 times higher than the standard MEMS devices. The mechanical resonant frequency for a gold device is 2.6 MHz and results in a switching time of 200 ns under a 32-V actuation voltage. Preliminary reliability tests at 13 GHz using bipolar actuation (plusmn30 V) and hot power switching have been performed on five 4 times 4 devices at 100 mW for 20 billion cycles, and at 500 mW for 5 billion cycles with no failures. A 4 times 4 array has also been used in the design of a tunable CPW resonator at 19.3 GHz with a 21% tuning range and 1.6-dB insertion loss. The authors believe that miniature MEMS devices will be very useful in the future for high-reliability MEMS and reconfigurable networks.
TL;DR: In this paper, a novel compact ultra-wideband antenna with band-notched function is proposed and implemented, where the radiating patch consists of a binomial function edge and is fed by coplanar waveguide.
Abstract: A novel compact ultra-wideband antenna with band-notched function is proposed and implemented. The radiating patch consists of a binomial function edge and is fed by coplanar waveguide. The size of the UWB antenna is minimized to 30 × 27.4 mm2. A new type of π-shaped slot is embedded to obtain the band-notched characteristic in the 5 GHz WLAN band. The center frequency of the notched band can be varied from 5.2 to 5.8 GHz by properly selecting the parameter values. The measured results are in good agreement with the simulated ones. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2656–2658, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23717
TL;DR: In this paper, the temperature and power dependence of the resonance frequency and frequency noise of superconducting niobium thin-film coplanar waveguide resonators carried out at temperatures well below 9.2 K were investigated.
Abstract: We present measurements of the temperature and power dependence of the resonance frequency and frequency noise of superconducting niobium thin-film coplanar waveguide resonators carried out at temperatures well below the superconducting transition (Tc=9.2 K). The noise decreases by nearly two orders of magnitude as the temperature is increased from 120 to 1200 mK, while the variation of the resonance frequency with temperature over this range agrees well with the standard two-level system (TLS) model for amorphous dielectrics. These results support the hypothesis that TLSs are responsible for the noise in superconducting microresonators and have important implications for resonator applications such as qubits and photon detectors.
TL;DR: In this article, measurements on microwave coplanar resonators designed for quantum bit experiments were described, and the resonant frequency shows a high sensitivity to magnetic field applied perpendicular to the plane of the film, with a quadratic dependence for the fundamental, second, and third harmonics.
Abstract: We describe measurements on microwave coplanar resonators designed for quantum bit experiments. Resonators have been patterned onto sapphire and silicon substrates, and quality factors in excess of a million have been observed. The resonant frequency shows a high sensitivity to magnetic field applied perpendicular to the plane of the film, with a quadratic dependence for the fundamental, second, and third harmonics. Frequency shift of hundreds of linewidths can be obtained with no change in the quality factor.
TL;DR: In this article, a tunable impedance-matching network is presented, which consists of a II-structure with tunable components made of varactors in series with inductors.
Abstract: This paper presents the design, fabrication, and characterization of a compact narrowband tunable impedance-matching network. A prototype was fabricated in hybrid technology using coplanar waveguide transmission lines and surface-mounted components. The network consists of a II-structure with tunable components made of varactors in series with inductors. Simulations and measurements are in good agreement. A new measurement methodology suitable for tunable impedance-matching networks is proposed. The results show that complex impedances with magnitudes varying from 6 Omega to 1 kOmega can be matched at 1 GHz and tuned in a 50% bandwidth. In addition, nonlinear measurements were done to fully characterize the network. The 1-dB compression point is reached at an input power of 20 dBm, while the input power for the third-order intermodulation intercept point is 21.3 dBm for a 1-kHz offset between the two input frequencies.
TL;DR: In this article, the authors measured the quality factor (Q) and hence the losses of thin film superconducting Nb coplanar waveguide resonators fabricated with processes and materials similar to those used for Josephson effect qubits, where such losses can cause significant decoherence.
Abstract: We measured the quality factor (Q) and hence the losses of thin film superconducting Nb coplanar waveguide resonators fabricated with processes and materials similar to those used for Josephson effect qubits, where such losses can cause significant decoherence. Intrinsic Q-values range from several thousand to almost 106 depending on the process details. Reactive ion etching appears to reduce the resonator Q-values and the lift-off process can also degrade the Q-value for some resists. The resistivity of the Si substrates affects the intrinsic Q at 1 K, where the resonators were measured. The Q-values obtained for optimized processing are sufficiently high as to suggest that qubits fabricated by a similar technique would not be limited by losses associated with the film or substrate.
TL;DR: In this paper, a narrowband trisection substrate-integrated waveguide elliptic filter with coplanar waveguide (CPW) input and output ports is proposed and demonstrated for X-band applications.
Abstract: A narrowband trisection substrate-integrated waveguide elliptic filter with coplanar waveguide (CPW) input and output ports is proposed and demonstrated for X-band applications. The filter is formed by incorporating metallized vias in a substrate (RT/Duroid) to create cross-coupled waveguide resonators. The result is an attenuation pole of finite frequency on the high side of the passband, therefore exhibiting asymmetric frequency response. The fabricated trisection filter with a centre frequency of 10.05 GHz exhibits an insertion loss of 3.16 dB for 3% bandwidth and a return loss of -20 dB. The rejection is larger than 15 dB at 10.37 GHz.
TL;DR: In this paper, an elevated-coplanar waveguide (ECPW) is proposed for an intermediate section of a coplanar-to-substrate integrated waveguide transition.
Abstract: In this letter, an elevated-coplanar waveguide (ECPW) is proposed for an intermediate section of a coplanar waveguide (CPW)-to-substrate integrated waveguide (SIW) transition. The ECPW is used to attain a gradual mode matching and to achieve the consequent wide bandwidth. The measurement results show 70% fractional bandwidth at 10 dB return loss and 0.9 dB insertion loss from 19 to 40 GHz. We expect that the proposed SIW transition plays an important role for the integration of high-Q SIW with CPW circuits, such as millimeter-wave system-in-package (SiP) using SIW circuits.
TL;DR: In this paper, a broadband ferromagnetic resonance (FMR) measurement has been carried out by using a rectifying effect in two sets of wires, one wire is deposited on the middle strip line of the coplanar waveguide and another is deposited between two strip lines of the CPW, measuring the FMR induced by in-plane and out-of-plane magnetic fields, respectively.
Abstract: The broadband ferromagnetic resonance (FMR) measurement has been carried out by using a rectifying effect in two sets of ${\text{Ni}}_{81}{\text{Fe}}_{19}$ wires. One wire is deposited on the middle strip line of the coplanar waveguide (CPW) and another is deposited between two strip lines of the CPW, measuring the FMR induced by in-plane and out-of-plane magnetic fields, respectively. The FMR frequency is defined by detecting the magnetoresistance oscillation due to the magnetization dynamics induced by a radio frequency (rf) field. The magnetic-field dependence of the resonance frequency and the rectification spectrum are analytically interpreted based on our uniform magnetization precession model. These findings reveal that two distinct rectifying signals are anticipated by a rf field and a rf current, which can easily be controlled by engineering the ferromagnetic wire shape and the external field orientation. These fundamental understandings are crucial for future rf device applications in spintronics.
15 Jun 2008
TL;DR: Inkjet printing technology was utilized to fabricate transmission lines on a glass substrate in this paper, where the conductivity of the sintered silver structures were 1/6 that of bulk silver after sintering at a temperature much lower than the melting point.
Abstract: Inkjet printing technology was utilized to fabricate transmission lines on a glass substrate. 50 micron resolution was realized using 10 pL drop volumes on a Corning 7740 glass substrate. This can be further improved by applying other methods as described in this paper. The conductivity of the sintered silver structures were 1/6 that of bulk silver after sintering at a temperature much lower than the melting point of bulk silver. A comparison of the DC resistance of the sintered silver shows that it can be a match for electroplated and etched copper. Printed Coplanar lines demonstrated losses of 1.62 dB/cm at 10 GHZ and 2.65 dB/cm at 20 GHz.
TL;DR: In this article, a high-speed polarization-insensitive photoconductor based on intersecting InP nanowires synthesized between a pair of hydrogenated silicon electrodes deposited on amorphous SiO2 surfaces prepared on silicon substrates was demonstrated.
Abstract: We demonstrate a high-speed polarization-insensitive photoconductor based on intersecting InP nanowires synthesized between a pair of hydrogenated silicon electrodes deposited on amorphous SiO2 surfaces prepared on silicon substrates. A 14-ps full width at half maximum de-embedded impulse response is measured, which is the fastest reported response for a photodetector fabricated using nanowires. The high-speed electrical signal measurements from the photoconductor are performed by an integrated coplanar waveguide transmission line. The demonstrated ability to grow intersecting InP nanowires on hydrogenated microcrystalline Si surfaces will facilitate the construction of ultra-fast photodetectors on a wide range of substrates.
TL;DR: In this article, a superconducting coplanar waveguide resonator with fundamental frequencies from 2 to 9 GHz and loaded quality factors ranging from a few hundreds to a several hundred thousands reached at temperatures of 20m K was designed.
Abstract: We have designed and fabricated superconducting coplanar waveguide resonators with fundamental frequencies from 2 to $9 \rm{GHz}$ and loaded quality factors ranging from a few hundreds to a several hundred thousands reached at temperatures of $20 \rm{mK}$. The loaded quality factors are controlled by appropriately designed input and output coupling capacitors. The measured transmission spectra are analyzed using both a lumped element model and a distributed element transmission matrix method. The experimentally determined resonance frequencies, quality factors and insertion losses are fully and consistently characterized by the two models for all measured devices. Such resonators find prominent applications in quantum optics and quantum information processing with superconducting electronic circuits and in single photon detectors and parametric amplifiers.
TL;DR: In this article, the authors developed a technology to fabricate fully metallic doubly clamped beams working as nanomechanical resonators and measured with a magnetomotive detection scheme, the beams, made of polycrystalline metal films, show as good quality as previously reported ones made of single crystal materials, such as Si, GaAs, AlN, and SiC.
Abstract: We developed a technology to fabricate fully metallic doubly clamped beams working as nanomechanical resonators. Measured with a magnetomotive detection scheme, the beams, made of polycrystalline metal films, show as good quality as previously reported ones made of single crystal materials, such as Si, GaAs, AlN, and SiC. Our method is compatible with the conventional fabrication process for nanoscale electronic circuits and thus offers a possibility of easily integrating the beams into superconducting charge and flux qubits and single-electron transistors as well as coupling them to coplanar waveguide resonators.
TL;DR: In this paper, a self-aligned planarization technique has been adopted to reduce the capacitance of the electroabsorption modulator (EAM), and the influence of residual reflection at the modulator facet on the small signal modulation response is investigated.
Abstract: High-speed AlGaInAs multiple-quantum-well (MQW) electroabsorption modulated lasers (EMLs) based on an identical epitaxial layer (IEL) integration scheme are developed for 40-Gb/s optical fiber communication systems. A self-aligned planarization technique has been adopted to reduce the capacitance of the electroabsorption modulator (EAM). The IEL structure EML chips exhibit a small signal modulation bandwidth around 40 GHz. The influence of residual reflection at the modulator facet on the small signal modulation response is investigated. Submount containing a grounded coplanar waveguide (GCPW) transmission line is used for packaging the EML chips into transmitter modules. The optimization of the GCPW structure to suppress resonances in frequency response due to parallel-plate modes is presented. Clear eye opening under 40-Gb/s nonreturn-to-zero (NRZ) modulation has been demonstrated for the packaged EML module.
TL;DR: In this paper, a compact multiband printed slot antenna fed by a asymmetric coplanar strip for multiband applications is presented, which has an overall dimension of only 31 × 15 mm2 and can be used for wireless local area network (WLAN) applications in the 2.4-2.4 GHz, 5.15-5.35 GHz and 5.825 GHz frequency range.
Abstract: A novel compact multiband printed slot antenna fed by a asymmetric coplanar strip for multiband applications is presented. The prototype printed on a substrate of dielectric constant 4.4 with an overall dimension of only 31 × 15 mm2 is proposed for wireless local area network (WLAN) applications in the 2.4–2.48 GHz, 5.15–5.35 GHz, and 5.725–5.825 GHz frequency range. The coplanar design, simple feeding technique, and compactness make it easy for the integration of the antenna into circuit boards. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 3080–3083, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23882