Coplanar waveguide

In this paper, a novel wideband directional coupler using coplanar waveguide multilayer slot-coupled technique is presented and implemented. The coupler uses two coplanar waveguide lines etched on two layers and coupled through an hexagonal slot etched on the common ground plane located between these layers. Firstly, conformal mapping techniques were used to obtain analytic closed-form expressions for the even-and odd-mode characteristic impedances. Secondly, using this approach, a new design of the directional coupler was performed. Both simulation and experimental results show a good performance in terms of bandwidth.

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

S. Simion1,2, G. Sajin1, R. Marcelli3, G. Bartolucci4 and F. Craciunoiu1 1 National Institute for Research and Development in Microtechnologies, Bucharest, Romania, e-mails: stefan.simion@yahoo.com, gsajin@imt.ro, floreac@imt.ro 2 Military Technical Academy, ...

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.

Open-and short-circuit terminated series stubs in finite-width coplanar waveguide (FCPW) fabricated on highresistivity Si are experimentally characterized over the frequency range of 2-40 GHz. In coplanar waveguide (CPW), these stubs are typically placed in the center conductor, but in FCPW, the stubs may also be placed in the ground planes resulting in novel circuit elements with characteristics that make the stubs useful for matching circuits and filters. Equivalent circuit models for the stubs are presented, and it is shown that when the stub is in the ground plane the resonant frequency is equal, the inductance and resistance is halved, and the capacitance is double the values of the same stub in the center conductor. Furthermore, it is shown that by varying the stub position in the ground plane, higher Q stubs can be obtained.

Resistive attenuator is used to reduce incident RF power and for impedance matching due to its absorptive and dissipative nature. A resistive 5 dB attenuator has been designed for an electromechanically selectable attenuators module. The electromechanical switch structure necessitates the attenuator to be designed to approximate a coplanar waveguide. As the attenuator has to work up to 67 GHz, parasitics of the attenuator circuit and the peripheral mechanical components had to be dealt with. Three dimensional EM field simulations were performed to understand the effect of the parasitics by monitoring the field patterns. Modification to the coplanar waveguide structure was introduced to overcome the parasitic degradation. A  topology 5 dB attenuator has been successfully developed with attenuation flatness of 0.25 dB and return loss less than -10dB up to 67 GHz.

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, 2 nd harmonic power of -47 dBm and 3 rd of -57 dBm are measured for a thru calibration structure on oxidized high-resistivity silicon (HRS) substrates, and 2 nd harmonic of -23 and 3 rd 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 2 nd and 3 rd 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.

The coplanar waveguide (CPW) structure is subdivided into five classes based on substrate thickness, backside metallization, and ground plane width. Radiation and guided modes are studied in each class, and their effects on loss and dispersion are described. For coplanar waveguides, dispersion due to interaction with surface wave parallel-plate modes in the substrate strongly depends on the ground-to-ground spacing (W+2G). If this spacing is small compared to dielectric wavelength and substrate thickness, both dispersion and radiation losses are minimized. In finite ground plane cases, small ground-to-ground spacing compared to substrate thickness is necessary to avoid the excitation of the microstrip mode and to minimize the deviation of the CPW mode from the odd mode of the ideal line. Limitations on the reduction of (W+2G) come from conductor loss, which imposes a minimum width requirement on the center conductor. If substrate thickness is to be kept large compared with this dimension, it is inevitable that, at high frequencies, the operation of the CPW will not be below the cutoff frequency of surface wave modes. However, the interaction of the CPW mode with surface wave modes is negligible for integrated circuit applications when ground-to-ground spacing is small compared with dielectric wavelength

A critical component of the millimeter-wave superheterodyne receiver is the local oscillator (LO) which is used to pump the low-noise mixer. Frequency multipliers have been used for many years to produce LO power. Current technology uses the whisker-contacted Schottky varactor diode which is inherently very fragile, expensive to fabricate, difficult to optimize, and requires as many as three mechanical tuners. This report describes the design, fabrication, and evaluation of four planar frequency multipliers. The 'direct-replacement' design demonstrates how a discrete planar varactor can replace a whisker-contacted varactor in a waveguide-type 75/225 GHz tripler and yield comparable performance. The fully monolithic (MMIC) balanced-varactor 80/160 GHz doubler and balanced-varactor 80/240 GHz tripler designs illustrate that MMIC technology is practical throughout the millimeter-wave band. Finally, a high-power 31/94 GHz tripler design is presented. These MMIC multipliers are t...

This article presents a very compact coplanar waveguidefed planar monopole antenna for ultrawideband (UWB) applications. The antenna consists of a palmate leaf-shaped radiator with a modified shaped ground plane on the same side of the substrate. The measured impedance bandwidth of the proposed antenna is from 3.08 to over 14 GHz with a ratio of about 4.6:1 for VSWR 2. Experimental results show that the proposed antenna has stably omnidirectional H-plane radiation patterns with low cross-polarization level and average peak gain of 3 dBi across the UWB. The antenna dimensions are restricted to 13.5 3 14.8 3 0.8 mm 3 .

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

A transition from coplanar waveguide (CPW)-tomicrostrip with vias is often used in wafer-probe measurements. This paper shows how field and impedance matching are used to develop a wideband transition. This paper demonstrates how the presence and placement of the vias affect the bandwidth and alters the impedance of the transition. The measured results on a transition show that a wideband transition with return loss better than 10 dB and an insertion loss less than 1.5 dB up to 36.64 GHz is obtained. The measurements show excellent agreement with simulation. The work presented in this paper provides a better understanding about a CPW-to-microstrip transition with vias as well as design procedures and principles that can be utilized to facilitate the realization of a broadband CPW-to-microstrip transition with vias.

The scattering of guided waves by a conductive post placed inside a rectangular waveguide with a step discontinuity on its sidewalls is analyzed through an integral-equation formulation. The interaction between post and discontinuity is examined with use of the Green's function. Numerical computations are carried out based on the mode-matching technique, providing a stable and accurate solution. An equivalent-circuit model is developed from the electromagnetic analysis and the computed scattering -parameters. The developed solution accuracy is validated with simulation software. became an Associate Professor with the Department of Electrical Engineering, NTUA, and in 1987, he became a Professor. He has authored or coauthored over 120 papers in refereed international journals, and has authored three books in Greek on microwaves, fiber-optics telecommunications, and radar systems. His research interests include electromagnetic scattering, propagation of electromagnetic waves, fiber-optic telecommunications, and high-speed circuits operating at gigabit/second rates. Since 1988, he has been the national representative of Greece to the Technical Telecommunication Committee, European Cooperation in the Field of Scientific and Technical Research (COST), and has actively participating in several COST telecommunications projects.

The paper considers a transition (balun) from coplanar waveguide (CPW) to coplanar stripline (CPS) which is nonresonant and suitable for feeding UWB antennas such as tapered slot antennas (Vivaldi antennas in particular), bow-tie antennas and other. Some numerical and experimental results are presented that show performance of the transition alone and as a feeder for a Vivaldi antenna.

In this article, a duals-band metamaterial antenna with a new composite right/left-handed (CRLH) unit cell configuration is proposed. The antenna is a coplanar waveguide (CPW) base which uses quarter wave resonators without via. Both sides of the CPW ground plane are short circuited to the CRLH-transmission line. The dimension is 31 mm 3 22 mm 3 1.52 mm, with electrical size of 0.23 k o 3 0.17 k o 3 0.011 k o at 2.26 GHz, and which is compact in size. Resonance frequency of the negative mode can be altered by controlling the loop currents. Peak gains of 1.74 and 2.69 dBi are obtained at 2.26 and 2.89

This paper describes the design rules of a compact microstrip patch antenna with polarization reconfigurable features (right-handed circular polarization (CP)/left-handed CP). The basic antenna is a circular coplanar-waveguide (CPW)-fed microstrip antenna excited by a diagonal slot and the CPW open end. This device is developed for short-range communications or contactless identification systems requiring polarization reconfigurability to optimize the link reliability. First, experimental and simulated results are presented for the passive version of the antenna excited by an asymmetric slot. A reconfigurable antenna using beam-lead p-i-n diodes to switch the polarization sense is then simulated with an electrical modeling of the diodes. Finally, the efficiency reduction resulting from the diode losses is discussed.

The views, opinions and/or findings contained in this report are those of the author(s) and should not be construed as an official Department of the Army position, policy, or decision, unless so designated by other documentation. 12a. DISTRIBUTION/AVAILABILITY STATEMENT

Mode conversion at the transition between grounded coplanar waveguide (GCPW) and microstrip line is demonstrated. Experimental results show the effect of overmoding in a conductor-backed coplanar waveguide on the transition behavior. A simple micromachining solution is used to cancel the parasitic modes triggered by the transition in the GCPW feed line. This results in an insertion loss of 0.3 dB and a return loss better than −18 dB from 75 to 110 GHz. The transition can prove very useful for millimeter-wave packaging and interconnects.

Recently, spiral inductors have widely been used instead of resistors in the design of matching circuits to enhance the thermal noise performance of a wireless transceiver. However, such elements usually have low quality factor (Q) and may encounter the self-resonance in microwave-frequency band which permits its use in higher frequencies, and on the other hand, they occupy the large on-chip space. This paper presents a new design theory for the impedance-matching circuits for a single-chip SiGe BiCMOS receiver front-end for 2.4 GHz-band wireless LAN (IEEE 802.11b). The presented matching circuits are composed of conductor-backed coplanar waveguide (CPW) meander-line resonators and impedance (K) inverter. The prototype front-end receiver is designed, fabricated and tested. A few of the measured results to verify the design theory are presented.

In this paper, a design and analysis of compact coplanar waveguide-fed ultra wideband slot antenna is presented. The proposed antenna has simple structure consisting octagon shape on a square patch the overall dimension of the antenna come around 29mmX29mmX1.6mm and fed by 50Ω probe feed. The impedance matching and radiation characteristics of the designed structure are investigated by using MOM based IE3D TM . The simulation results show that the antenna offers excellent performance for UWB application ranging from 7GHz to 10.65GHz. The proposed antenna achieved -10dB impedance bandwidth cover about 41%. The proposed antenna gain is 7.5dBi is achieved. This antenna configuration would be quiet useful for UWB indoor application as it is easy to fabricate and integrate with RF circuitry.

This article proposes three design topologies of coplanar waveguide elliptic low pass filters. The design procedure is simple and explained in detail for the first topology. Numerical results are provided using the commercially available simulation softwares IE3D and HFSS to show the validity of the design with very good agreement. The proposed filters yield less than 0.1 dB attenuation in the passband (0-2 GHz), with a controllable slope of the transition between passband and stopband. The width of the rejection band is increased by simple filter cascading resulting in a passband to stopband ratio of up to 1:6.

A novel Asymmetric Coplanar Strip (ACS) fed antenna with Defected Ground Structure (DGS) suitable for dual application is presented. The Method of Moments (MoM) based mentor graphics IE3D electromagnetic solver has been used for this design. Dual band operation has been obtained by modifying the ground plane of the proposed design with spur-slots. It has been fabricated and tested with the overall size of 21x15x1.6 mm 3. The measured results indicate that the proposed antenna yields <-10dB impedance bandwidth of 13.13% and 9.86% which meets the requirement of 3.5GHz and 5.5GHz Wireless Local Area Network (WLAN) and World Wide Interoperability Microwave Access (WiMAX) applications. The approximate lumped equivalent circuit extraction for the proposed DGS fed dual band antenna has been discussed in detail. Because of its stable radiation patterns with low cross polarization,miniature size, high average antenna gain of 2.5dBi and good electromagnetic characteristics, the proposed antenna is a promising candidate for dual mode wireless communication devices.

A novel uniplanar coplanar waveguide-fed quasi-Yagi antenna is presented. The originality of this design is because of its feed selection and its elliptical structure and in doing so achieving a wide bandwidth and compact size. An X-band prototype is developed and measures a bandwidth of 40%, with 3.2 dBi gain and 11 dB front-to-back ratio measured at 10 GHz. The antenna is realised on a high dielectric constant substrate and is compatible with monolithic microwave integrated circuits and solid-state devices.

We report the fabrication of single and few-channel carbon nanotube (CNT) Schottky diodes on high-frequency compatible substrates using horizontally aligned CNT arrays and dissimilar metal contacts in a coplanar-waveguide geometry. Rectification of ac signals in the range of 100 MHz-40 GHz is examined and the observed cutoff frequencies are used to compute the Schottky junction capacitance of the devices, which is strongly CNT-length-dependent and appears dominated by stray capacitance between the CNT channel and metal electrode, in agreement with electrostatic simulations.

For use in millimeter-wave integrated circuits, theoretical and experimental design data for various useful capacitive transmission lines in coplanar waveguide on gallium arsenide are presented. Multifinger and metal-insulator-metal (MIM) lines enabling low characteristic impedance in the order of 10 as well as broad-band capacitive coupled transmission lines are investigated. Simple design rules and accurate models validated with measurements up to 120 GHz demonstrate that such planar transmission lines can be used in monolithic microwave integrated circuits (MMIC's) to extend the impedance range and the design flexibility with respect to the conventional CPW.

Satellite communication and Wireless communication has been developed rapidly in the past decades and it has already a dramatic impact on human life. In the present time in commercial and government communication system has been develop low cost, minimal weight, minimal size, low profile antenna, the capable of maintaining the performance over a large spectrum of frequencies. This paper emphasizes the use of Defected Ground Structure (DGS) technique in microstrip patch antenna. This circular disc or patch antenna is designs are simulated using the IE3D software. And try to find out the different-different condition the maximum gain output and bandwidth. The simulated and measured results are in close agreement which validates the role of the designed antenna for operation in wireless applications from 5-15GHz. A comparison is drawn between the performances of the antennas in terms of gain, return loss, VSWR of the antennas.

We present experimental and simulation data of subterahertz attenuation of coplanar waveguides (CPWs) with wide and narrow ground planes. Experimental data are obtained by using a subpicosecond measurement technique based on electrooptic sampling. While time-domain data qualitatively describe the attenuation characteristics, they are converted to the frequency domain by a Fourier transform to give a quantitative interpretation. Simulation data are obtained by full-wave analysis and compared with the experimental results. It is shown that the simulation results consistently agree with experimental results. Furthermore, in the case of CPWs with wide ground planes, both of them are consistent with analytical theory. While CPWs with narrow ground planes have not been analytically studied, our results show that they suffer considerably lower attenuation, which we attribute to a reduced coupling between the CPW mode and substrate modes. The effects of ground-plane width and line dimensions on the attenuation characteristics are discussed in detail.

We report the development of completely uniplanar broadband balanced push-pull FET amplifiers using slot line and coplanar waveguide. The amplifiers employ broad-band uniplanar baluns to achieve the push-pull function over a wide bandwidth. One amplifier, designed in the unconditionally stable region, exhibits a gain of 3.5-5 dB over the frequency range of 5.4-10 GHz and an output 1-dB compression point of 19 dBm at 10 GHz. The other amplifier was designed in the potentially unstable range and achieves a high gain between 10-11 dB from 2 to 4 GHz and an output 1-dB compression point of 17 dBm at 4 GHz. These results show the feasibility of the push-pull FET amplifier configuration using uniplanar technology for microwave and millimeterwave integrated circuits and systems.

parylene-N is used as a dielectric layer to create ultra low-loss 3-D vertical interconnects and coplanar waveguide (CPW) transmission lines on a CMOS substrate. Insertion loss of 0.013 dB for a 3-D vertical interconnect through a 15-m-thick parylene-N layer and 0.56 dB/mm for a 50-CPW line on the parylene-N layer (compared to 1.85 dB/mm on a standard CMOS substrate) are measured at 40 GHz. L-shaped, U-shaped, and T-junction CPW structures are also fabricated with underpasses that eliminate the discontinuities arisen from the slot-line mode and are characterized up to 40 GHz. A 3-D low-noise amplifier using these postprocessed structures on a 0.13-m CMOS technology is also presented along with the investigation of parasitic effects for accurate simulation of such a 3-D circuit. The 3-D circuit implementation reduces the attenuation per unit length of the transmission lines, while preserving the CMOS chip area (in this specific design) by approximately 25%. The 3-D amplifier measures a gain of 13 dB at 2 GHz with 3-dB bandwidth of 500 MHz, noise figure of 3.3 dB, and output 1-dB compression point of +4.6 dBm. Roomtemperature processing, simple fabrication, low-loss performance, and compatibility with the CMOS process make this technology a suitable choice for future 3-D CMOS and BiCMOS monolithic microwave integrated circuit applications that currently suffer from high substrate loss and crosstalk. Index Terms-Coplanar waveguide (CPW), low-noise amplifier (LNA), parylene-N, 3-D integration, vertical interconnect.

The study of the dispersion properties of planar transmission lines including metallic losses with the generalized transverse resonance method is formalized in building an equivalent network of the cross-section which specifies the relationships between the tangential components of the fields on each side of the interfaces. Virtual sources represent the trial quantities chosen to describe the problem. With twoport type boundary conditions, the trial quantities are not easily defined from physical considerations, but the virtual sources obey to specific rules. This purpose is illustrated in studying the attenuation in lossy suspended coplanar transmission lines. Ľétude de la dispersion des lignes planaires présentant des pertes ohmiques par la méthode de la résonance transverse généralisée, se formalise au moyen ďun circuit équivalent de la section droite qui rend compte des relations entre les champs tangentiels aux interfaces. Des sources virtuelles représentent les grandeurs ďessai retenues pour formuler le problème. Comme les conditions aux limites sont de type quadripôle, ces grandeurs ďessai ne peuvent se déduire de considérations physiques, comme dans le cas sans perte, mais les sources virtuelles obéissent à certaines règles. Cette démarche est illustrée par ľétude de ľatténuation de lignes coplanaires suspendues.

This article presents the design of a novel and compact coplanar antenna using Metamaterials (MTM) and Micro Electro Mechanical Systems (MEMS). The antenna is based on coplanar waveguide (CPW) technology; therefore, the signal and ground are on the same plane, presenting lower dielectric losses and high signal integrity. The designed antenna can be tuned in the frequency range from 5.3 to 5.8 GHz by MEMS capacitors, and it is useful for wireless communications applications, especially beam steering systems. Finally, the design, 3D full-wave simulations and MEMS simulations are presented. Index Terms -Metamaterial (MTM), Transmission Line (TL), Coplanar (CPW), Composite Right/Left Handed (CRLH), Micro-Electro-Mechanical Systems (MEMS).

Recently, spiral inductors have widely been used instead of resistors in the design of matching circuits to enhance the thermal noise performance of a wireless transceiver. However, such elements usually have low quality factor (Q) and may encounter the self-resonance in microwave-frequency band which permits its use in higher frequencies, and on the other hand, they occupy the large onchip space. This paper presents a new design theory for the impedance-matching circuits for a single-chip SiGe BiCMOS receiver front-end for 2.4 GHz-band wireless LAN (IEEE 802.11b). The presented matching circuits are composed of conductor-backed coplanar waveguide (CPW) meanderline resonators and impedance (K) inverter. The prototype frontend receiver is fabricated and measured. A few of the measured results to verify the design theory are presented.

This paper presents the design of a microstrip-CPW transition where the CPW line propagates close to slotline mode. This design allows the solution to be determined entirely though analytical techniques. In addition, a planar via-less microwave crossover using this technique is proposed. The experimental results at 5 GHz show that the crossover has a minimum isolation of 32 dB. It also has low in-band insertion loss and return loss of 1.2 dB and 18 dB respectively over more than 44 % of bandwidth.

This paper describes the design and characterization of a 2×2 sequential-rotation array (SRA) of novel circularly polarized antenna elements. The required feed phase-vector is achieved using a coplanar feeding network. The network is, for the first time, built using CPW lines in MCM-D technology. The array operates in the K-band around 25 GHz. The analysis is carried out both theoretically and experimentally. The results show that the sequential rotation increases the axial ratio bandwidth and enhances the isolation between the RHCP and LHCP polarizations. The proposed antenna element and sequential-rotation array enjoy high impedance bandwidth, high circular polarization bandwidth, and good isolation between the RHCP and the LHCP modes.

This paper compares four commonly used on-wafer calibration methods including multiline thru-reflect-line (TRL), line-reflect-reflect-match, line-reflect-match, and short-open-loadthru, for three diverse coplanar waveguide (CPW) circuits. The magnitudes and phases of 11 and 21 of the CPW circuits are compared to quantify how the specific calibration method influences measured scattering parameters. Special care is taken to ensure that the measured scattering parameters are normalized to the same reference impedance and reference plane for accurate comparison. The measured results are compared with full-wave simulations to provide additional assessment of accuracy. A method to de-embed the discontinuity of the CPW at the probe tip and the CPW of the test structures is presented. The effect of probe-to-device-under-test discontinuity is effectively modeled by one-or two-section of shunt capacitor and series inductor. The results show that the multiline TRL calibration method provides the highest transmission coefficient repeatability on not well-matched circuits and highest accuracy on the three circuits in this paper up to 40 GHz.

This paper presents the design and performance of 110-GHz low noise amplifier MMICs, based on coplanar technology, and utilizing 120-nm gate-length metamorphic HEMTs. Thanks to a cascode device, a single-stage amplifier achieves 8-dB small signal gain, with less than 4-dB noise figure at 105 GHz, within a chip size of only 0.725 mm/sup 2/. The 2- and 3-stage LNAs exhibit small signal gains of more than 15- and 22-dB, respectively over the 100-115 GHz frequency range, with associated measured noise figures of 4.5 dB at 105 GHz; the chip area for these circuits are less than 2- and 3 mm/sup 2/. To the author&#39;s knowledge, these results are amongst the lowest noise figures reported to date for uniplanar amplifier MMICs operating at these frequencies.

Metamorphic high electron mobility transistor (mHEMT) technologies with 50 and 35 nm gate length were developed for the fabrication of submillimeter-wave monolithic integrated circuits (S-MMICs) operating at 300 GHz and beyond. Heterostructures with very high electron sheet density of 6.1u10 12 cm -2 and 9800 cm 2 /Vs electron mobility were grown on 4" GaAs substrates using a graded quaternary InAlGaAs buffer layer. For proper device scaling channel-gate distance and source resistance were reduced. Maximum transconductance of 2500 mS/mm and a transit frequency of 515 GHz were achieved for the 35 nm mHEMT with 2 u 10 µm gate-width. Already the 50 nm technology allows the realization of S-MMIC operation frequencies up to 320 GHz, the current limit of on-wafer probe availability. A compact four-stage H-band amplifier circuit based on a grounded coplanar waveguide (GCPW) layout is presented in 50 and 35 nm technology, respectively. The 50 nm mHEMT amplifier has a linear gain of 19.5 dB at 320 GHz and more than 15 dB between 240 and 320 GHz. The same amplifier utilizing 35 nm gate-length transistors achieves more than 20 dB gain within the entire H-band from 220 to 320 GHz.

Stock market prediction is important and of great interest because successful prediction of stock prices may promise attractive benefits. These tasks are highly complicated and very difficult. In this paper, we investigate the predictability of stock market return with Adaptive Network-Based Fuzzy Inference System (ANFIS). The objective of this study is to determine whether an ANFIS algorithm is capable of accurately predicting stock market return. We attempt to model and predict the return on stock price index of the Istanbul Stock Exchange (ISE) with ANFIS. We use six macroeconomic variables and three indices as input variables. The experimental results reveal that the model successfully forecasts the monthly return of ISE National 100 Index with an accuracy rate of 98.3%. ANFIS provides a promising alternative for stock market prediction. ANFIS can be a useful tool for economists and practitioners dealing with the forecasting of the stock price index return.

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.