Showing papers on "Coplanar waveguide published in 2004"

CPW-fed planar ultra wideband antenna having a frequency band notch function

Abstract: A CPW-fed planar ultra-wideband antenna with hexagonal radiating elements is presented. The antenna also has a frequency band notch characteristic. By inserting a V-shaped thin slot on the hexagonal radiating element, the narrow frequency band notch has been created very close to the desired frequency.

Multiband waveguide reflector antenna feed

Abstract: A multiband waveguide reflector antenna feed comprises waveguide feeds in a concentric architecture. A waveguide feed is located in the center and coaxial waveguide feeds are disposed around the center feed. The waveguide feeds may be all-metallic with the center feed operating in a TE 11 mode and the coaxial feeds operating in a coaxial TE 11 mode. The waveguide feeds may have electromagnetic band gap (EBG) surfaces on waveguide surfaces. The center waveguide feed may have an EBG outer conductor surface and operate in a circular waveguide TEM mode. The coaxial waveguide feeds may have EBG inner and outer conductors and operate in a circular waveguide TEM mode. The coaxial feeds may have EBG inner conductors and near perfect electrical conductor (PEC) outer conductors and operate in a circular waveguide-like TE 11 mode or may comprise EBG outer conductors and PEC inner conductors and operate in a quasi-TEM waveguide mode.

Surface-passivated high-resistivity silicon substrates for RFICs

Abstract: Surface passivation of high-resistivity silicon (HRS) by amorphous silicon thin-film deposition is demonstrated as a novel technique for establishing HRS as a microwave substrate. Metal-oxide-silicon (MOS) capacitor measurements are used to characterize the silicon surface properties. An increase of the quality factor (Q) of a 10-nH spiral inductor by 40% to Q=15 and a 6.5-dB lower attenuation of a coplanar waveguide (CPW) at 17 GHz indicate the beneficial effect of the surface passivation for radio frequency (RF) and microwave applications. Regarding CPW attenuation, a nonpassivated 3000-/spl Omega//spl middot/cm substrate is equivalent to a 70-/spl Omega//spl middot/cm passivated substrate. Surface-passivated HRS, having minimum losses, a high permittivity, and a high thermal conductivity, qualifies as a close-to-ideal radio frequency and microwave substrate.

Design and fabrication of scanning near-field microwave probes compatible with atomic force microscopy to image embedded nanostructures

Abstract: Design, fabrication, and characterization of near-field microwave scanning probes compatible with an atomic force microscope (AFM) for imaging of embedded nanostructures are discussed. The microwave probe discussed here bridges the frequency gap between the existing local probe microscopy systems, and enables localized microwave spectroscopy and imaging of molecules and nanostructures. The probe consists of a coaxially shielded heavily doped silicon tip, and an aluminum (Al) coplanar waveguide. The coaxial tip structure was formed by a thick photoresist and plasma etching process, enabling the silicon apex to protrude through a well-defined aperture in the Al layer. Using this technique, probes with 10-/spl mu/m-high coaxial tips of 5-nm apex radius and 500-nm aperture radius were realized. The aperture confines the electromagnetic fields in the exposed tip region, allowing microwave measurements with high spatial resolution. The mechanical and electrical characterizations of the microwave probes were performed to ensure their compliance with the requirement of an AFM, as well as that of the microwave measurements. Finally, simultaneous AFM and microwave imaging of standard AFM samples with grid structures was performed for the first time. The lateral spatial resolution of the microwave scans was approximately 50 nm at 2.8 GHz, compared to 100 nm for the AFM scans. The ability of the microwave signal to penetrate inside the sample opens new possibilities in hyperspectral and multimodal imaging of nanostructures. Correlations between AFM images and the microwave images enable proper registration and referencing of the microwave properties to landmarks in the topographic AFM images.

Left handed coplanar waveguide band pass filters based on bi-layer split ring resonators

Abstract: A new type of compact band pass filters based on planar structures with three metal levels is proposed. The central layer consists on a coplanar waveguide (CPW) with periodic wire connections between the central strip and ground planes. In the upper and lower metal levels, split ring resonators (SRRs) are etched and aligned with the slots. The wires make the structure to behave as a microwave plasma, with a negative effective permittivity covering a wide frequency range. SRRs, which are magnetically coupled to the CPW, provide a negative magnetic permeability in a narrow frequency range above their resonant frequency. The result is a band pass structure which supports wave propagation in a frequency interval where negative permittivity and permeability coexist. The bandwidth of the structure can be controlled by tuning the resonant frequency of the upper and lower SRRs and the distance between SRRs. Fabricated prototype devices exhibit very low insertion losses in the pass band (<1.5 dB) and high frequency selectivity.

Wide-band slot antennas with CPW feed lines: hybrid and log-periodic designs

Abstract: In microwave and millimeter wave applications, slot antennas fed by coplanar waveguide (CPW) lines are receiving increasing attention. These antennas have several useful properties, such as a wider impedance bandwidth compared to microstrip patch antennas, and easier integration of solid-state active devices. In this paper novel CPW-fed wideband slot antennas are presented. The design procedure of CPW-fed hybrid slot antennas (HSA) having impedance bandwidths (VSWR<2) up to 57% is described. Theoretical and measured results are shown. We also describe the design procedure of a CPW-fed log-periodic slot antenna (LPSA). The impedance matching and the radiation characteristics of these structures were studied using a method of moment technique. Simulated and measured results for different dielectrics are presented.

CPW-fed compact meandered patch antenna for dual-band operation

Abstract: By inserting a meandering slit at the edge of a rectangular patch printed in a single layer and fed by a coplanar waveguide (CPW) transmission line, a novel compact dual-frequency antenna is obtained. The designed antenna, with, including ground plane, only 20 mm in height and 30 mm in width, can operate at both 2.0 and 5.32 GHz bands and provide sufficient bandwidths for the UMTS and WLAN systems, respectively.

A coplanar waveguide permeameter for studying high-frequency properties of soft magnetic materials

Abstract: The high-frequency relative permeability of thin permalloy films was measured in the frequency and time domain using a microwave coplanar waveguide (CPW). Frequency domain measurements using a loop permeameter were performed for comparison. The Fourier transform of the time domain measurement, and the frequency domain measurement on the CPW agree closely, both showing a higher-frequency secondary resonance peak which is not seen with the loop measurement. This resonance likely arises from the lowest-order perpendicular standing spin wave mode of the permalloy film.

Coplanar waveguide structures loaded with split-ring resonators

Abstract: Coplanar waveguide (CPW) transmission lines periodically coupled to split-ring resonators (SRRs) are analyzed, designed, and characterized. Due to inductive coupling between the lines and SRRs, signal propagation is inhibited in the vicinity of the resonant frequency of the rings. The result is a stop-band behavior that can be of interest for the elimination of frequency parasitics in CPW-based devices. Two different approaches are envisaged: a uniplanar structure, where CPW and rings share the same metal level; and a bimetal structure with SRRs etched on the back side of the substrate. It has been found that the latter exhibits almost negligible insertion losses in the pass band, and sharp cutoff and a high level of rejection in the stop band, with few unit cells. Since ring dimensions are small compared to the signal wavelength at resonance, the proposed SRR-CPWs are very promising for the design of miniaturized microwave circuits. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 40: 3–6, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.11269

High performances of shielded LTCC vertical transitions from DC up to 50 GHz

Abstract: This paper reports on research on two generic shielded vertical transitions in low-temperature cofired ceramic technology These interconnections are simulated and optimized by three-dimensional electromagnetic simulations The first circuit, a coplanar waveguide (CPW) or microstrip-to-stripline transition, presents great experimental performances from dc up to 50 GHz, and the second, a CPW-to-waveguide transition, is defined for Q-band applications

Wideband slot antennas for wireless communications

Abstract: The paper presents a wideband antenna design, referred to as the planar volcano-smoke slot antenna (PVSA), useful for wideband wireless communication applications. The antenna is a planar slot – with an appearance reminiscent of a volcanic crater and a puff of smoke – and is fed by a coplanar waveguide (CPW) to achieve the wide bandwidth. A coax-to-CPW transition, which is crucial for achieving wide bandwidth performance, is modelled and introduced into the antenna, and the impedance, pattern bandwidths and radiation patterns of the antenna are investigated. It is demonstrated that the PVSA has an impedance bandwidth between 0.8 and 6.7 GHz (for a VSWR <2.3) and a pattern bandwidth ranging from 0.8 GHz to 2.0 GHz for the radiation in the upper hemisphere. Finally, an absorber-backed PVSA is designed to suppress the radiation along the side- and back-directions. A front/back (F/B) ratio of better than 15dB has been achieved over the band with an absorbing enclosure backed by a PEC plate.

Wideband coplanar-waveguide bandpass filters with good stopband rejection

Abstract: Wideband coplanar-waveguide (CPW) bandpass filters based on the cascade of CPW lowpass and highpass periodic structures are proposed. The upper and lower stopband characteristics of proposed bandpass filter can be easily designed by separately adjusting the lowpass and highpass sections, respectively. Specifically, two wideband CPW bandpass filters with sharp roll-off at passband edges and good stopband rejection are demonstrated.

Characteristics of bow-tie slot antenna with tapered tuning stubs for wideband operation

Abstract: CHARACTERISTICSOFBOW-TIESLOTANTENNAWITHTAPEREDTUNINGSTUBSFORWIDEBANDOPERATIONA.A.Eldek,A.Z.Elsherbeni,andC.E.SmithDepartmentofElectricalEngineeringCenterofAppliedElectromagneticSystemsResearch(CAESR)TheUniversityofMississippiUniversity,MS38677,USA—Thecharacteristicsofabow-tieslotantennawithtaperedtuning stubs fed by a coplanar waveguide (CPW) are investigated.Theeffectsoftheantennadimensionalparametersarestudiedthroughsimulation results and design procedure is developed and verified fordifferentfrequencybands. Theantennashowswidebandcharacteristicsfor radar and wireless communication applications. Numericalsimulations and measurements indicate that 73% bandwidth can beobtainedusingthedevelopeddesignprocedure.1 Introduction2 AntennaGeometryandParametricStudy3 Measurements4 RadiationPattern5 ConclusionAcknowledgmentReferences1. INTRODUCTIONIn applications where size, weight, cost, performance, ease ofinstallation, and aerodynamic profile are constrains, low profileantennas like microstrip and printed slot antennas are required.Printedslotantennasfedbycoplanarwaveguide(CPW)haveseveral

Flexible differential interconnect cable with isolated high frequency electrical transmission line

Abstract: A high speed flexible interconnect cable includes a number of conductive layers and a number of dielectric layers. Conductive signal traces, located on the conductive layers, combine with the dielectric layers to form one or more high speed electrical transmission line structures. The transmission line structure may be realized as a grounded coplanar waveguide structure, a microstrip structure, a stripline structure, or the like. The cable can be coupled to destination components using a variety of connection techniques, e.g., direct bonding to a circuit substrate, direct soldering to a flip chip, mechanical attachment to a component, or integration with a circuit substrate. The cable can also be terminated with any number of known or standardized connector packages, e.g., SMA, GPPO, or V connectors.

The SiOG-based single-crystalline silicon (SCS) RF MEMS switch with uniform characteristics

Abstract: This paper details single-crystalline silicon (SCS) direct contact radio frequency microelectromechanical systems (RF MEMS) switch designed and fabricated using an SiOG (silicon-on-glass) substrate, so as to obtain higher fabrication and performance uniformity compared with a conventional metal switch. The mechanical and electrical performances of the fabricated silicon switch have been tested. In comparison with a conventional metallic MEMS switch, we can obtain higher productivity and uniformity by using SCS, because it has very low stresses and superior thermal characteristics as a structural material of the switch. Also, by using the SiOG substrate instead of an SOI substrate, fabrication cost can be significantly reduced. The proposed switch is fabricated on a coplanar waveguide (CPW) and actuated by electrostatic force. The designed chip size is 1.05 mm/spl times/0.72 mm. Measured pull-in voltage and actuation voltage were 19 V and 26 V, respectively. Eighteen identical switches taken randomly throughout the wafer showed average and standard deviation of the measured pull-in voltage of 19.1 and 1.5 V, respectively. The RF characteristics of the fabricated switch from dc to 30 GHz have been measured. The isolation and insertion loss measured on the four identical samples were -38 to -39 dB and -0.18 to -0.2 dB at 2 GHz, respectively. Forming damping holes on the upper electrode leads to a relatively fast switching speed. Measured ON and OFF time were 25 and 13 /spl mu/s, respectively. In the switch OFF state, self-actuation does not happen up to the input power of 34 dBm. The measured holding power of the fabricated switch was 31 dBm. Stiction problem was not observed after 10/sup 8/ cycles of repeated actuation, but the contact resistance varied about 0.5-1 /spl Omega/ from the initial value.

Coplanar quarter-wavelength quasi-elliptic filters without bond-wire bridges

Abstract: This paper presents the design and experimental results of two coplanar quarter-wavelength microwave filters operating at a frequency of approximately 3 GHz. Coplanar designs are of particular interest because they are less sensitive to the thickness of the dielectric substrate than other transmission-line types such as a microstrip. One of the designs has a quasi-elliptic frequency response. In addition, the design also eliminates problems with unbalancing of the ground planes normally present in coplanar structures. Bond wires between the ground planes are not required. This paper describes in detail the structure of the resonators and how they are coupled together to form a filter.

Low-loss coplanar waveguides interconnects on low-resistivity silicon substrate

Abstract: This paper describes fabrication, characterization and simulation of low-loss coplanar waveguide (CPW) interconnects on low-resistivity silicon substrate The fabrication of CPWs is low-temperature (below 250/spl deg/C) and incorporates a spin-on low-k dielectric benzocyclobutene (BCB) and self-aligned electroplating of copper The performance of CPWs is evaluated by high-frequency characterization and EM simulation CPWs with different line width (W) and line spacing (S) are investigated and compared Using a BCB layer as thick as 20 /spl mu/m, CPW fabricated on a low-resistivity silicon substrate exhibits an insertion loss of 3 dB/cm at 30 GHz

electrical contacting method

Abstract: A method for contacting printed conductors terminating at the edge of a circuit board with printed conductors of a MID component includes: on a panel which includes the circuit board, producing the printed conductors of the circuit board in a layout in which the printed conductors are extended past a partition line which defines the edge of the circuit board; providing the panel with through holes along the partition line in the region of the printed conductors; electroplating through the through holes; isolating the circuit board from the panel; and positioning the circuit board in relation to the MID component and soldering the printed conductors of the circuit board to the printed conductors of the MID component. Rear electrical contacting areas are provided on a back side of the panel near the partition line, and the printed conductors are connected to the rear electrical contacting areas via the through holes.

Super compact split ring resonators CPW band pass filters

Abstract: Coplanar waveguide (CPW) band pass filters consisting on signal-to-ground wire connections alternating with series gaps, and split ring resonators (SRRs) etched in the back substrate slide, underneath the slots, are presented for the first time. It is demonstrated that by properly tuning SRR dimensions, a narrow pass band below the cutoff frequency of the wired/gaped CPW structure can be obtained. The relevant characteristics of the designed structure are: insertion losses below 4 dBs in the allowed band, out of band rejection above 30 dBs, and very high transition slopes with only three SRR stages. Due to subwavelength operation of SRRs, the proposed structures are very compact with potential application to the fabrication of planar filters for future communication transceivers.

Millimeter-wave tune-all bandpass filters

Abstract: Distributed microelectromechanical varactors on a coplanar waveguide have been used to design a two- and four-pole bandpass tune-all filters. The two-pole initial bandwidth is 6.4% at 44.05 GHz with a mid-band insertion loss of 3.2 dB and with matching better than 15 dB. The four-pole initial bandwidth is 6.1% at 43.25 GHz with a mid-band insertion loss of 6.5 dB and with matching better than 10 dB. The use of microelectromechanical system bridges allows a continuous tuning for both center frequency and bandwidth. The varactors biasing network has been designed so that the center frequency and bandwidth can be tuned separately. The two-pole filter center frequency can be changed from 44.05 to 41.55 GHz (5.6% tuning range), while the bandwidth can be independently changed from 2.8 to 2.05 GHz. The four-pole filter center frequency can be changed from 43.25 to 40.95 GHz (5.3% tuning range) and the bandwidth can be changed from 2.65 to 1.9 GHz.

A DC to 100 GHz high performance ohmic shunt switch

Abstract: This paper presents a wideband ohmic shunt switch implemented on a coplanar waveguide (CPW). The switch is fabricated using a dielectric membrane with patterned metallic contacts that short the CPW line when it is electrostatically actuated. The switch has been extrapolated from measurements. It exhibits low insertion loss, good matching, high isolation from DC to W band (>20 dB up to 100 GHz) and very good mechanical properties with switching time <1/spl mu/s.

Novel wide-band coplanar waveguide-to-rectangular waveguide transition

Abstract: A new coplanar waveguide (CPW)-to-rectangular waveguide transition is proposed for wide-band millimeter-wave applications. The transition has an in-line structure, which provides easy fabrication of the CPW circuit and waveguide block. An X-band (8.2-12.4 GHz) model has been designed and tested. Measurements of a back-to-back double transition have yielded a return loss of over 17 dB and an insertion loss of less than 0.5 dB over the full X-band. These results agree well with the simulated results obtained with a commercial electromagnetic structure simulator. In addition, this type of a transition has been designed and used for a local oscillator feed with a full F-band (90-140 GHz) coverage of a submillimeter-wave general-purpose harmonic mixer.

Transmission line phase shifter with controllable high permittivity dielectric element

Abstract: A transmission line phase shifter ideally suited for use in low-cost, steerable, phased array antennas suitable for use in wireless fidelity (WiFi) and other wireless telecommunication networks, in particular multi-hop ad hoc networks, is disclosed. The transmission line phase shifter includes a wire transmission line, such as a coaxial, stripline, microstrip, or coplanar waveguide (CPW) transmission line. A high-permittivity dielectric element that overlies the signal conductor of the wire transmission line is used to control phase shifting. Phase shifting can be electromechanically controlled by controlling the space between the high-permittivity dielectric element and the signal conductor of the wire transmission line or by electrically controlling the permittivity of the high-permittivity dielectric element.

Etched-facet semiconductor optical component with integrated end-coupled waveguide and methods of fabrication and use thereof

Abstract: An optical apparatus comprises a semiconductor optical device waveguide formed on a semiconductor substrate, and an integrated end-coupled waveguide formed on the semiconductor substrate. The integrated waveguide may comprise materials differing from those of the device waveguide and the substrate. Spatially selective material processing may be employed for first forming the optical device waveguide on the substrate, and for subsequently depositing and forming the integrated end-coupled waveguide on the substrate. Spatially selective material processing enables accurate spatial mode matching and transverse alignment of the waveguides, and multiple device waveguides and corresponding integrated end-coupled waveguides may be fabricated concurrently on a common substrate on a wafer scale. The integrated end-coupled waveguide may be adapted for fulfilling one or more functions, and the device waveguide and/or integrated waveguide and/or spatially selective material processing steps may be adapted in a variety of ways for achieving the needed/desired degree of end-coupling.

Membrane supported Yagi-Uda antennae for millimetre-wave applications

Abstract: This paper addresses for the first time the design, fabrication and 'on wafer' characterisation of membrane supported Yagi-Uda coplanar waveguide fed antenna structures, operating in the 45 GHz frequency range. The antennae were fabricated on 1.4 /spl mu/m thin SiO/sub 2//Si/sub 3/N/sub 4/ membranes obtained by micromachining of high resistivity silicon, using a backside reactive ion etching process. This approach has assured almost free-space operating conditions for the Yagi-Uda antennae and the dry backside etching process has allowed the effect of the bulk silicon wall that supports the membrane in the main radiation direction to be minimised. The design was based on electromagnetic simulations made using the Zeland IE3D software package. The antenna structures, measured 'on wafer', have shown a minimum return loss of 15 dB and a gain of about 7 dBi. Very good agreement has been observed between experimental and simulated results.

A 24GHz, +14.5dBm fully-integrated power amplifier in 0.18 /spl mu/m CMOS

Abstract: A 24 GHz, +14.5 dBm fully-integrated power amplifier with 50 /spl Omega/ input and output matching is fabricated using 0.18 /spl mu/m CMOS transistors. To enable this, a shielded-substrate coplanar waveguide transmission line structure is used to achieve low loss and small area. The power amplifier achieves a power gain of 7 dB and a maximum single-ended output power of +14.5 dBm with a 3 dB bandwidth of 3.1 GHz, while drawing 100 mA from a 2.8 V supply. The chip area is 1.26 mm/sup 2/.

Novel CMOS low-loss transmission line structure

Abstract: As operating speeds increase low-loss interconnect structures such as transmission lines become critical in the design of RF and high speed digital circuits. This paper presents a novel low-loss transmission line structure. We discuss the importance of transmission line structures, including coplanar and grounded coplanar structures. Grounded coplanar waveguide (GCPW) structures are enhanced to reduce the substrate loss. The primary goal of new interconnect topology, stacked GCPW (S-GCPW), is to reduce the loss by shaping the electric fields under the signal line. 3D electromagnetic wave simulations are used to verify the efficacy of the new transmission line structures. The insertion loss for a 4 mm long S-GCPW structure is 1.62 dB@50 GHz (0.41dB/mm) while the insertion loss for a 4 mm long traditional GCPW structure is 3.28 dB (0.82 dB/mm) in a 0.12 /spl mu/m SOI CMOS technology.

A widely tunable RF MEMS end-coupled filter

Abstract: A three-pole tunable end-coupled filter from 6 to 10 GHz was developed with a broad 35% tuning range. This tuning range was realized by switching distributed loading structures with radio frequency microelectromechanical systems (RF MEMS) capacitive switches. By tuning the coupling capacitors as well as the loading capacitors, the filter achieved a constant fractional bandwidth of 15/spl plusmn/0.3% and an insertion loss ranging from 3.3 dB to 3.8 dB over the entire band. Digital switching ensured good thermal stability, and microstrip transmission lines provided lower insertion loss than with coplanar waveguide. Future improvements are expected to decrease the insertion loss to below 2.1 dB.

Potential applications of PBG engineered structures in microwave engineering: Part I

Abstract: The second part of this article reviews the potential applications of electromagnetic bandgap (EBG) structures in enhancing the performance of waveguides and antennas. A conductor-backed coplanar waveguide (CB-CPW) free of spurious transmission and a transverse electromagnetic (TEM) mode waveguide with uniform field distribution are reported. In the case of antennas, the improved performance in terms of phase control, gain, directivity, beam steering and bandwidth available in the recent literature is outlined. The authors' work on PBG-assisted compact phased arrays and VSAT antennas is presented.

Finite coplanar waveguide width effects in pulsed inductive microwave magnetometry

Abstract: The effect of finite coplanar waveguide (CPW) width on the measurement of the resonance frequency in thin ferromagnetic films has been characterized for pulsed inductive microwave magnetometry. A shift in resonant frequency is a linear function of the ratio of sample thickness to CPW width. The proportionality constant is experimentally determined to be 0.74±0.1 times the saturation magnetization of the film. The frequency shift may be modeled as arising from an effective magnetic-anisotropy field.