Showing papers on "Coplanar waveguide published in 2005"

Millimeter-wave CMOS design

Abstract: This paper describes the design and modeling of CMOS transistors, integrated passives, and circuit blocks at millimeter-wave (mm-wave) frequencies. The effects of parasitics on the high-frequency performance of 130-nm CMOS transistors are investigated, and a peak f/sub max/ of 135 GHz has been achieved with optimal device layout. The inductive quality factor (Q/sub L/) is proposed as a more representative metric for transmission lines, and for a standard CMOS back-end process, coplanar waveguide (CPW) lines are determined to possess a higher Q/sub L/ than microstrip lines. Techniques for accurate modeling of active and passive components at mm-wave frequencies are presented. The proposed methodology was used to design two wideband mm-wave CMOS amplifiers operating at 40 GHz and 60 GHz. The 40-GHz amplifier achieves a peak |S/sub 21/| = 19 dB, output P/sub 1dB/ = -0.9 dBm, IIP3 = -7.4 dBm, and consumes 24 mA from a 1.5-V supply. The 60-GHz amplifier achieves a peak |S/sub 21/| = 12 dB, output P/sub 1dB/ = +2.0 dBm, NF = 8.8 dB, and consumes 36 mA from a 1.5-V supply. The amplifiers were fabricated in a standard 130-nm 6-metal layer bulk-CMOS process, demonstrating that complex mm-wave circuits are possible in today's mainstream CMOS technologies.

Ultra-wideband bandpass filter with hybrid microstrip/CPW structure

Abstract: A novel ultra-wideband (UWB) bandpass filter (BPF) is presented using the hybrid microstrip and coplanar waveguide (CPW) structure. A CPW nonuniform resonator or multiple-mode resonator (MMR) is constructed to produce its first three resonant modes occurring around the lower end, center, and higher end of the UWB band. Then, a microstrip/CPW surface-to-surface coupled line is formed and modeled to allocate the enhanced coupling peak around the center of this UWB band, i.e., 6.85GHz. As such, a five-pole UWB BPF is built up and realized with the passband covering the entire UWB band (3.1-10.6GHz). A predicted frequency response is finally verified by the experiment. In addition, the designed UWB filter, with a single resonator, only occupies one full-wavelength in length or 16.9mm.

Study of CPW-fed circular disc monopole antenna for ultra wideband applications

Abstract: The paper presents a study of coplanar waveguide (CPW) fed circular disc monopole antenna for ultra-wideband (UWB) applications. A circular disc monopole printed on a dielectric substrate and fed by a 50 /spl Omega/ CPW on the same layer can yield an ultra-wide -10 dB return loss bandwidth with satisfactory radiation patterns. The performance and characteristics of the antenna are investigated in order to understand its operation. Good agreement has been obtained between the simulation and experiment.

An ultrawideband bandpass filter using broadside-coupled microstrip-coplanar waveguide structure

Abstract: This paper presented an ultra-wideband (UWB) bandpass filter using broadside-coupled microstrip-coplanar waveguide structure. The filter consists of a microstrip line coupled to a coplanar waveguide (CPW) that was fabricated on the ground of the microstrip line. The proposed filter has been simulated, fabricated and measured for UWB system. The measured results demonstrated the UWB properties from 3.0 GHz to 10.63 GHz (-10 dB bandwidth) and the potential to be wider. A threesection filter shown insertion loss at central frequency is about 0.32 dB and very flat over the whole band. The group delay, which is important to an impulse radio UWB system, is about 0.42 ns over the most central band and less than 0.95 ns over the whole band. The filter also exhibited a good performance outside the band, both at low frequency end (to meet FCC limit) and high frequency end higher than 18 GHz with insertion loss larger than 30 dB.

Integrated plasmon and dielectric waveguides

Abstract: A metal waveguide is coupled to a dielectric waveguide to obtain transmission of light in a plasmon mode along an edge of the metal waveguide. Efficient, broadband light transmission is obtained, achieving a low insertion loss, using standard processing tools. An efficient integrated optical circuit is obtained.

Analysis and design of current probe transition from grounded coplanar to substrate integrated rectangular waveguides

Abstract: The transition between a grounded coplanar waveguide (GCPW) and a substrate integrated rectangular waveguide (SIRW) is investigated in this paper. The proposed scheme makes use of a current probe to transfer power between the two dissimilar transmission lines. A computer-aided-design-oriented analytical model is developed in order to optimize the geometrical dimensions of the transition. By using the GCPW instead of the microstrip line to interface the SIRW, substrate thickness can be increased without incurring a penalty due to transmission loss. Therefore, it is possible to achieve higher Q components. Experiments at 28 GHz show that an effective bandwidth of 10% can easily be obtained. The insertion loss is less than 0.73 dB over the bandwidth of interest.

Dual-frequency annular-ring slot antennas fed by CPW feed and microstrip line feed

Abstract: The dual-frequency properties of a dual annular-ring slot antenna fed by coplanar waveguide (CPW) and microstrip feedline are presented and experimentally studied. The proposed antenna is constructed by dual concentric annular-ring slots fabricated on FR4 substrate with single feed. The proposed slot antennas have good impedance matching for the two operating frequencies with a frequency ratio ranging about 1.34/spl sim/3.11 and 1.4/spl sim/1.74 can be achieved for CPW-fed and microstrip-fed.

A novel CPW‐fed ultra‐wideband antenna design

Abstract: A novel ultra-wideband (UWB) antenna fed by coplanar waveguide (CPW) is designed, fabricated, and measured for UWB communications. It is designed to work on a substrate TMM4 of thickness 0.762 mm and relative permittivity 4.5, and to operate from 3.1 to 8.3 GHz. Details of the proposed antenna design and the measured results are presented and discussed. Measured insertion loss is almost constant across the frequency band and the group-delay variation is less than 1 ns, thus indicating that the proposed antenna is a good candidate for UWB applications. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 44: 393–396, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20646

Design of a 5.8-GHz rectenna incorporating a new patch antenna

Abstract: This paper presents a rectifying antenna (rectenna) designed in a finite ground coplanar waveguide (FG-CPW) circuit. The new rectenna element is based on a new patch antenna and a new band-stop filter, in the form of compact CPW resonant cell (CCRC), located between the antenna and the rectifying diode. The novel coplanar patch antenna with about 9-dBi gain is proposed for the rectenna. The CCRC is adopted to suppress the second harmonic from radiation. With the use of this band-stop filter, a radio-frequency-to-direct-current (RF-to-dc) conversion efficiency of 68.5% using a 270-/spl Omega/ load resistor is obtained.

Design of a multiband CPW-fed monopole antenna using a particle swarm optimization approach

Abstract: A novel coplanar waveguide fed planar monopole antenna for multiband operation is presented in this paper. By embedding appropriate slits into the 50 /spl Omega/ feeding line, good impedance matching for multiresonant mode is obtained. The evolutionary design process of using a particle swarm optimization (PSO) algorithm in conjunction with the method of moments is employed to effectively obtain the geometry parameters of the antenna for optimum multiband performance. Prototypes of the obtained optimized design have been constructed and experimentally studied. The measured results explore good multiband operation with 10 dB impedance bandwidths of 55%, 8.5%, and 4.4% at bands of 2.51, 3.98, and 5.24 GHz, respectively, which cover the personal communication system and 2.4/5.2 GHz wireless local-area network operating bands, and show good agreement with the numerical prediction. Good monopole-like radiation patterns and antenna gains over the operating bands have also been observed. Effects of the patch size on the antenna performance and implementation of the physical PSO for the optimized configuration are all examined and discussed in detail.

Liquid crystalline polymer and multilayer polymer-based passive signal processing components for RF/wireless multi-band applications

Abstract: The present invention provides all organic fully-packaged miniature bandpass filters, baluns, diplexers, multiplexers, couplers and a combination of the above manufactured using liquid crystalline polymer (LCP) and other multilayer polymer based substrates These devices are manufactured using one or more LCP layers having integrated passive components formed thereon to provide the density and performance necessary for multi-band wireless devices In the designs involving multiple LCP layers, the LCP layers are separated by prepeg layers In accordance with an aspect of the present invention, coplanar waveguide, hybrid stripline/coplanar waveguide and/or microstrip topologies are utilized to form the integrated passive components, and the devices can be mass produced on large area panels at least 18 inches by 12 inches with line widths smaller than 10 um

Novel Butler matrix using CPW multi-layer technology

Abstract: In this paper, a new configuration of a coplanar waveguide (CPW) beamforming 8-port Butler matrix operating at 5.8 GHz is presented. This matrix is based on a novel CPW multilayer directional coupler. The main objective of the proposed coupler is to avoid using crossovers as employed in conventional Butler matrices. To examine the performance of the proposed matrix, an experimental prototype was fabricated and measured, and the obtained results confirm the proposed approach.

CPW-fed circular disc monopole antenna for UWB applications

Abstract: This paper proposes and studies a novel design of a coplanar waveguide (CPW) fed circular disc monopole antenna for ultra wideband (UWB) applications. A circular disc monopole printed on a dielectric substrate and fed by a 50 /spl Omega/ CPW on the same layer is demonstrated numerically and experimentally to yield an ultra wide -10 dB bandwidth with omnidirectional radiation patterns over the entire bandwidth. The effect of the disc dimension on the antenna performance is also investigated.

A general circuit model for defected ground structures in planar transmission lines

Abstract: This paper presents a general circuit model for planar transmission line defected ground structures (DGS) that exhibits multi electromagnetic band gaps or stop bands in frequency responses. The proposed equivalent circuit consists of lumped elements that can be easily extracted from full-wave EM simulations. It is simple and accurate for modeling a wide range of DGS in microstrip and coplanar waveguide over a broad bandwidth. Excellent agreement with EM simulations/measurements is demonstrated.

Design of an ultra wide-band printed monopole antenna using FDTD and genetic algorithm

Abstract: This letter presents an ultra wide-band (UWB) antenna with a printed monopole structure fed by a coplanar waveguide (CPW) line. The antenna is analyzed by using the finite-difference time-domain (FDTD) method and genetic algorithm (GA) to achieve an ultra wide bandwidth characteristic. The measured frequency response shows an impedance bandwidth of 7.25GHz or 104.7% over 3.3 to 10.55GHz for VSWR less than 2.

High frequency design and characterization of SU-8 based conductor backed coplanar waveguide transmission lines

Abstract: The epoxy-based negative photoresist SU8 is widely, used within the MEMS (microelectromechanical systems) community, and is well known for its ability to form thick layers with high aspect ratios and for its chemical resistance. However, only a few papers have investigated the electrical properties of this material and mostly within the MEMS area or at lower frequency ranges. This paper presents the design and characterization of conductor-backed coplanar waveguide (CBCPW) transmission lines using SU-8 dielectric material. The coplanar transmission lines are carefully designed using EDA tools, and fabricated on a metallized glass substrate coated with SU-8 material. S-parameter measurements are performed from 45 MHz to 50 GHz using a vector network analyzer and a probe station. From these measurements, transmission line parameters such as characteristic impedance, attenuation constant, effective dielectric constant, loss tangent, etc, are determined. The design procedure, fabrication process and measurement results are described in this paper. To our knowledge, this is the first time the SU-8 material is characterized in microelectronics using CBCPW transmission lines.

Reconfigurable Broadband Microstrip Antenna Fed by a Coplanar Waveguide

Abstract: In this paper, a novel reconfigurable two-layer microstrip antenna fed using a coplanar waveguide through a slot/loop combination is investigated. The slot/loop combination allows for easy reconfigurability of the frequency band of operation by incorporating switches in the feed network. Furthermore, broad impedance bandwidths were obtained by using two substrate layers consisting of a high-er substrate that contains the feed network and a low-er substrate that contains two patches, one patch on either side of the substrate. The two substrates are not separated by a ground plane. Impedance bandwidths of about 23% were obtained for two selectable frequency bands using two switches. The two frequency bands obtained for the parameters chosen in this paper are 8.73-10.95 GHz and 7.68- 9.73 GHz.

Compact MMIC CPW and asymmetric CPS branch-line couplers and Wilkinson dividers using shunt and series stub loading

Abstract: Circuit size may be reduced by up to 60% by embedding series and shunt uniplanar stubs inside the main uniplanar line since this reuses physical space in the longitudinal direction. This size-efficient stub loading of the main uniplanar line results in robust options for designing compact K-band 90/spl deg/ hybrid couplers and Wilkinson dividers. The approach is confirmed by experimental results that agree well with theory up to at least 30 GHz using both coplanar waveguide (CPW) and asymmetric coplanar stripline (ACPS). Furthermore, these couplers and dividers do not use lumped inductors or capacitors and, consequently, have excellent design accuracy even at millimeter-wave frequencies. Additionally, it is shown that it is possible to design an ACPS 90/spl deg/ branch-line coupler without the conventional CPW quarter wavelength transformers used to match the input and output port characteristic impedances.

Planar excitation of Goubau Transmission Lines for THz BioMEMS

Abstract: We propose and demonstrate an original planar excitation of a single wire transmission line also known as Goubau-Line (G-Line). The excitation is based on an electromagnetic transition between a coplanar waveguide and the desired G-line in a planar configuration. We present some characteristics for this line such as its electromagnetic spatial distribution, its velocity, and results in the frequency domain analysis for the transitions. We will also show some results concerning the shape of the G-line and its influence on the transmission level. From these results, we show that there is a great interest for these structures in the field of biological characterization.

RF characterization and modeling of various wire bond transitions

Abstract: This paper presents radio-frequency (RF) characterization and modeling of various wire bond transitions between chips and packages. Test modules composed of Si chips and alumina packages are fabricated in conductor-backed (CB) structures, and they are characterized at frequencies up to 20 GHz. It is shown that the parallel plate resonance of the CB coplanar waveguide (CPW) persists in wire bonding transitions, and narrower-ground CPW-CPW transitions show better characteristics than wider-ground CPW-CPW transitions. The results of three-dimensional full-wave electromagnetic simulation on the test modules reproduce the measured results with a reasonable accuracy. Simple equivalent circuit modeling can reproduce the measured results of the narrower ground CPW transition with no resonance structures. Finally, the effects of bond wire length and impedance mismatch on RF performance are investigated.

Low-loss lateral micromachined switches for high frequency applications

Abstract: Two novel lateral metal-contact radio-frequency microelectromechanical system (RF MEMS) switches are reported. These switches are implemented with quasi-finite ground coplanar waveguide (FGCPW) configuration and actuated by applying electrostatic force on a high-aspect-ratio cantilever beam. It is demonstrated that the insertion loss of the switch is less than 0.2 dB up to 15 GHz and the isolation is higher than 20 dB up to 25 GHz. An RF model of the switches is used to analyse the effects of the switch design parameters and RF performance. The optimization of the switch mechanical design is discussed where the threshold voltage can be lower than 25 V. The lateral switches are fabricated by deep reactive ion etching (DRIE) process on a silicon-on-insulator (SOI) wafer with shadow mask technology.

Modeling of symmetric composite right/left-handed coplanar waveguides with applications to compact bandpass filters

Abstract: This study proposes an equivalent-circuit model for the composite right/left-handed (CRLH) coplanar waveguide (CPW) comprising the series interdigital capacitor and shunt meandering short-circuited stub inductor in symmetric configuration. The new technique for extracting the equivalent-circuit elements of the CRLH CPW, which include inductances, capacitances, and resistances to represent the left-handed, right-handed, and lossy characteristics, is developed based on the effective medium concept. The applications to the compact resonators and filters are presented to emphasize the unique features of the CRLH CPW. A novel CRLH CPW resonator with a 0/spl deg/ effective electrical length at resonance is proposed, which gives a 49.1% size reduction when compared with the conventional half-wavelength resonator at 5 GHz. Based on the zeroth-order CRLH CPW resonators, an inductively coupled two-pole bandpass filter with 5.4% 3-dB bandwidth and 2.7-dB insertion loss at 5 GHz is implemented, and it is 51.4% more compact than the conventional structure. A good agreement among the results of the full-wave simulation, equivalent-circuit model, published data, and measurement demonstrates the effectiveness of the proposed modeling technique. To suppress the higher order harmonic spurious passbands, the electromagnetic-bandgap CPW structures are incorporated into the proposed CRLH CPW filter.

Broad-band radial slot antenna fed by coplanar waveguide for dual-frequency operation

Abstract: A novel design of a broad-band radial slot antenna fed by a coplanar waveguide for dual-frequency operation is presented. Various frequency ratios, within the range of about 1.3 to 2.1, of the two operating frequencies can be obtained by varying the included angle between the radial slots and/or by varying the length of the central slot pair. The bandwidth of the lower operating band lies in the range of 2.4% to 9.7%, while that of the upper band is much wider and ranges from 17.4% to 23.2%. Radiation patterns at the two operating frequencies are broadside and bidirectional. Details of the antenna design and the experimental results are presented and discussed.

Wideband coplanar waveguide-to-rectangular waveguide transition using fin-line taper

Abstract: This letter introduces a new wideband coplanar waveguide-to-rectangular waveguide transition. The transition uses a uniplanar circuit in line with the waveguide, which eases the design and fabrication. The design does not require airbridges. Simulations and measurements of X-band (8.2-12.4 GHz) transitions based on both a low- and high-permittivity material (/spl epsiv//sub r/= 2.33 and 10.8) show that the transition works fine over the full frequency band. For /spl epsiv//sub r/= 2.33 the measured return and insertion loss of a back-to-back transition are more than 16 dB and less than 0.4dB, respectively. The corresponding values for /spl epsiv//sub r/= 10.8 are more than 10 dB and less than 1.0 dB, respectively, over 90% of the frequency band. The measured insertion loss values indicate losses of less than 0.14 dB and 0.36 dB at the center frequency for a single transition on a substrate with /spl epsiv//sub r/= 2.33 and 10.8, respectively.

Surface-passivated high-resistivity silicon as a true microwave substrate

Abstract: This paper addresses the properties of a surface-passivated (enhanced) high-resistivity silicon (HRS) substrate for use in monolithic microwave technology. The detrimental effects of conductive surface channels and their variations across the wafer related to the local oxide and silicon/silicon-dioxide interface quality are eliminated through the formation of a thin amorphous layer at the wafer surface. Without passivation, it is found that the surface channels greatly degrade the quality of passive components in HRS by masking the excellent properties of the bulk HRS substrate and by causing a spread in parameters and peak values across the wafer. Moreover, it is seen that the surface passivation leads to excellent agreement of the characteristics of fabricated components and circuits with those predicted by electromagnetic (EM) simulation based on the bulk HRS properties. This is experimentally verified for lumped (inductors and transformers) and distributed (coplanar waveguide, Marchand balun) passive microwave components, as well as for a traveling-wave amplifier, through which also the integration of transistors on HRS and the overall parameter control at circuit level are demonstrated. The results in this paper indicate the economically important possibility to transfer microwave circuit designs based on EM simulations directly to the HRS fabrication process, thus avoiding costly redesigns.

Design of a planar half-circle-shaped UWB notch antenna

Abstract: In this paper, we propose a small, lightweight, and low-cost ultra-wideband (UWB) antenna that exhibits a notch characteristic in the 5-GHz WLAN band (5.15–5.825 GHz) using a planar half-circle shape patch, a two-step matching stub, a coplanar waveguide (CPW)-type feed, and a hat-shaped slot. The notch frequency of the proposed antenna can be adjusted by controlling the slot length. The measured results are in reasonably good agreement with the simulated results. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 47: 9–11, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21065

Miniature RF MEMS switched capacitors

Abstract: This paper presents a paradigm shift in RF MEMS, and shows the development of miniature switched capacitors for RF applications. The MEMS bridges are 21 /spl mu/m long by 8 /spl mu/m wide, and are 150-300/sup x/ smaller than the standard Raytheon switch or other switched capacitors as presented in G. M. Rebeiz (2003). The bridges are integrated in an N /spl times/ M array implemented in coplanar waveguide t-lines (CPW). The bridges are 3400 /spl Aring/ thick, and are suspended 2400 /spl Aring/ above the CPW center conductor (with a 1600 /spl Aring/ SiN layer), resulting in an actuation voltage of 25 V. The measured capacitance ratio of a single bridge is 2.8, and that of a 3 /spl times/ 20 arrays is 1.9. These MEMS switched capacitors have a very high spring constant, and correspondingly a very high pull-up force per unit contact area with the dielectric layer. They are not sensitive to charging in the dielectric layer and also, are not sensitive to temperature variation. Also, the simulated switching time is 250 ns for gold switches and 110 ns for Al switches. We believe that this design is very useful for high reliability RF MEMS switches in the coming years.

A Si MMIC compatible ferroelectric varactor shunt switch for microwave applications

Abstract: This letter describes a ferroelectric thin-film based varactor shunt switch, for microwave and millimeterwave switching applications. Our implementation is based on a coplanar waveguide transmission line shunted by a ferroelectric varactor. The concept of switching ON and OFF is based on the dielectric tunability of the ferroelectric barium strontium titanium oxide (BST) thin-films. From experimental verification, the isolation of a switch with a varactor area of 75/spl mu/m/sup 2/ was approximately 20dB at 35GHz and the insertion loss was below 4.5dB up to 35GHz. This letter addresses the design and experimental verification of the first ferroelectric varactor shunt switch with an Si monolithic microwave integrated circuit compatible process.

Studies of CPW-fed equilateral triangular-ring slot antennas and triangular-ring slot coupled patch antennas

Abstract: Designs of coplanar waveguide (CPW)-fed equilateral triangular-ring slot antennas with tuning-stub and triangular-ring slot coupled patch antennas are proposed and experimentally investigated. The impedance matching of the resonant frequency can be obtained only by adjusting the tuning-stub length for the proposed triangular-ring slot antenna with tuning-stub. For the design of ring-slot coupled patch antenna, slightly changing the patch size causes the tunable frequency-ratio f/sub 2//f/sub 1/ between the first two operating frequencies to fall in the range of about 1.1-1.42. Details of the proposed designs are investigated by experimental as well as theoretical studies.

Pattern reconfigurable leaky-wave antenna design by FDTD method and Floquet's Theorem

Abstract: A pattern reconfigurable millimeter-wave coplanar waveguide leaky-wave antenna is designed by using the finite-difference time-domain (FDTD) method combined with Floquet's theorem and the simple linear interpolation technique. The concept of equivalent period is presented for mixed-periodic structures. The novel design process results in a reduction in the design time compared with that of the traditional FDTD method.