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Разработан и экспериментально исследован электрически перестраиваемый полосно-пропускающий СВЧ-фильтр (ППФ). Устройство состоит из двух короткозамкнутых резонаторов с кондуктивным подключением портов. Перестройка полосы пропускания реализована с помощью варакторных диодов, включенных в разомкнутый конец резонаторов и управляемых напряжением в диапазоне 1,5–12 В. По результатам макетирования получен фильтр с перестройкой полосы пропускания 15 %, максимальными вносимыми потерями 2,6 дБ и значением КСВН в рабочей полосе частот не хуже 2. За счет использования четвертьвол- новых резонаторов и дополнительных сосредоточенных емкостей, получены габариты изделия в пределах 12х15 мм., This paper presents the computer aided design and experimental investigation of electrically tuned bandpass microwave filter. The bandpass filter design is based on two regular shunt resonators with the conductive input/output port switching. The bandpass control is implemented by means of varactors which are loaded at the open end of the resonators and operate within the voltage range 1.5–12V. The following exper imental characteristics of the filter are obtained: the bandpass tuning range is 15 %, the maximal insertion loss is 2.6 dB and the VSWR within operational frequency band is 2. The outer dimensions of the filter are 12x15 mm. We achieve compact dimensions due to the use of quarter- wave resonators and extra lumped capacitor.

This paper presents a kind of broadband, low-loss tunable phase shifter based on transmission line metamaterial. An inherent high-pass backward-wave response property of a left-handed metamaterial based on coplanar waveguide (CPW) transmission line was used to realize a microwave phase shifter. The commercial software Ansoft HFSS was used to design and analyze for the transmission line metamaterial phase shifter structure, and the resulting S-parameters were used to characterize its performance. A transmission line metamaterial phase shifter was fabricated on Copper-Clad Board. The designed four unit-cells phase shifter provides a 0-190o continuous phase shift at 7.2 GHz using varactors biased from 0 V to 6 V with relatively low insertion loss.

This paper presents a kind of broadband, low-loss tunable phase shifter based on transmission line metamaterial. An inherent high-pass backward-wave response property of a left-handed metamaterial based on coplanar waveguide (CPW) transmission line was used to realize a microwave phase shifter. The commercial software Ansoft HFSS was used to design and analyze for the transmission line metamaterial phase shifter structure, and the resulting S-parameters were used to characterize its performance. A transmission line metamaterial phase shifter was fabricated on Copper-Clad Board. The designed four unit-cells phase shifter provides a 0-190o continuous phase shift at 7.2 GHz using varactors biased from 0 V to 6 V with relatively low insertion loss.

Four versions of the compact hexagonal-shaped monopole printed antennas for UWB applications are presented. The first proposed antenna has an impedance bandwidth of 127.48 % (3.1 GHz to 14 GHz), which satisfies the bandwidth for ultra-wideband communication systems. To reduce the foreseen co-channel interference with WLAN (5.2GHz) and X-Band systems (10GHz), the second and third antennas type were generated by embedding hexagonal slot on the top of the radiating patch. The integration of the half and full hexagonal slots created notched bands that potentially filtered out the sources of interference, but were static in nature. Therefore, a fourth antenna type with tuneable-notched bands was designed by adding a varactor diode at an appropriate location within the slot. The fourth antenna type is a dual-notch that was electronically and simultaneously tuned from 3.2GHz to 5.1GHz and from 7.25GHz up to 9.9GHz by varying the bias voltages across the varactor. The prototypes of the four antenna versions were successfully fabricated and tested. The measured results have good agreement with the simulated results.

Four versions of the compact hexagonal-shaped monopole printed antennas for UWB applications are presented. The first proposed antenna has an impedance bandwidth of 127.48 % (3.1 GHz to 14 GHz), which satisfies the bandwidth for ultra-wideband communication systems. To reduce the foreseen co-channel interference with WLAN (5.2GHz) and X-Band systems (10GHz), the second and third antennas type were generated by embedding hexagonal slot on the top of the radiating patch. The integration of the half and full hexagonal slots created notched bands that potentially filtered out the sources of interference, but were static in nature. Therefore, a fourth antenna type with tuneable-notched bands was designed by adding a varactor diode at an appropriate location within the slot. The fourth antenna type is a dual-notch that was electronically and simultaneously tuned from 3.2GHz to 5.1GHz and from 7.25GHz up to 9.9GHz by varying the bias voltages across the varactor. The prototypes of the four antenna versions were successfully fabricated and tested. The measured results have good agreement with the simulated results.

In this paper, the effect of changing the structure of split ring resonator SRR from circular to elliptical shape is presented and tested. The theoretical analysis of circular SRR (CSRR) is tested and its results are compared with the simulated ones. Comparison between both configurations is introduced. The new elliptical SRR (ESRR) can be adapted to operate in multi range of frequencies. The effect of gap position in ESRR resonant is also examined. When both gaps are moved but still aligned, the resonant frequency still the same. But when single gap is moved only the resonant frequency the resonant frequency in changed to reach its maximum value when both gaps are in the same position. Frequency tunability can be offered by loading a single variable capacitor between ESRR metallic rings.  The resonant frequency of the ESRR can be controlled by varying the capacitance of the varactor diode. Finite element method FEM is used to simulate the proposed structures using HFSS.

A standing wave oscillator (SWO) is a perfect clock source which can be used to produce a high frequency clock signal with a low skew and high reliability. However, it is difficult to tune the SWO in a wide range of frequencies. We introduce a frequency tunable SWO which uses an inversion mode metal-oxide-semiconductor (IMOS) field-effect transistor as a varactor, and give the simulation results of the frequency tuning range and power dissipation. Based on the frequency tunable SWO, a new phase locked loop (PLL) architecture is presented. This PLL can be used not only as a clock source, but also as a clock distribution network to provide high quality clock signals. The PLL achieves an approximately 50% frequency tuning range when designed in Global Foundry 65 nm 1P9M complementary metal-oxide-semiconductor (CMOS) technology, and can be used directly in a high performance multi-core microprocessor., QC 20160415

An equivalent circuit approach is adopted in this paper to analyze a novel varactor loaded phasing line, specifically designed to improve the frequency agility features of reconfigurable aperture-coupled reflectarray cell, through the use of a couple of microstrip radial stubs. The proposed analysis method is fruitfully implemented to perform a fast and preliminary investigation on the improvements provided by the radial shaped phasing line in terms of frequency agility of the reflectarray unit cell. The method is adopted to compare frequency performances of radial and linear phasing line geometries, allowing to effectively demonstrate the radial line geometry contribution to the enhancement of the unit cell frequency performances.

An equivalent circuit approach is adopted in this paper to analyze a novel varactor loaded phasing line, specifically designed to improve the frequency agility features of reconfigurable aperture-coupled reflectarray cell, through the use of a couple of microstrip radial stubs. The proposed analysis method is fruitfully implemented to perform a fast and preliminary investigation on the improvements provided by the radial shaped phasing line in terms of frequency agility of the reflectarray unit cell. The method is adopted to compare frequency performances of radial and linear phasing line geometries, allowing to effectively demonstrate the radial line geometry contribution to the enhancement of the unit cell frequency performances.

An equivalent circuit approach is adopted in this paper to analyze a novel varactor loaded phasing line, specifically designed to improve the frequency agility features of reconfigurable aperture-coupled reflectarray cell, through the use of a couple of microstrip radial stubs. The proposed analysis method is fruitfully implemented to perform a fast and preliminary investigation on the improvements provided by the radial shaped phasing line in terms of frequency agility of the reflectarray unit cell. The method is adopted to compare frequency performances of radial and linear phasing line geometries, allowing to effectively demonstrate the radial line geometry contribution to the enhancement of the unit cell frequency performances.

An equivalent circuit approach is adopted in this paper to analyze a novel varactor loaded phasing line, specifically designed to improve the frequency agility features of reconfigurable aperture-coupled reflectarray cell, through the use of a couple of microstrip radial stubs. The proposed analysis method is fruitfully implemented to perform a fast and preliminary investigation on the improvements provided by the radial shaped phasing line in terms of frequency agility of the reflectarray unit cell. The method is adopted to compare frequency performances of radial and linear phasing line geometries, allowing to effectively demonstrate the radial line geometry contribution to the enhancement of the unit cell frequency performances.

We report on the evaluation of Schottky barrier diode GaAs multipliers at cryogenic temperatures. A GaAs Schottky barrier diode model is developed for theoretical estimation of doubler performance. The model is used to predict efficiency of doublers from room to cryogenic temperatures. The theoretical estimation is verified experimentally using a 78 GHz doubler cooled down to 14 K. The observed efficiency improvement due to cooling is approximately 4 % per 100 degrees.

The work was based on digitally controlled oscillator for an all-digital PLL in 65nm process. Phase locked loop’s were used in most of the application for clock generation and recovery as well. As the technology grows faster in the existinggeneration, there has to be quick development with the technique. In such case ananalog PLL which was used earlier gradually getting converted to digital circuit.All-digital PLL blocks does the same work as an analog PLL blocks, but thecircuits and other control circuitry designed were completely in digital form, becausedigital circuit has many advantages over analog counterpart when they arecompared with each other. Digital circuit could be scaled down or scaled up evenafter the circuits were designed. It could be designed for low power supply voltageand easy to construct in a 65 nm process. The digital circuit was widely chosento make life easier. In most of the application PLL’s were used for clock and data recovery purpose,from that perspective jitter will stand as a huge problem for the designers. Themain aim of this thesis was to design a DCO that should bring down the jitter asdown as possible which was designed as standalone, the designed DCO would belater placed in an all-digital PLL. To understand the concept and problem aboutjitter at the early stage of the project, an analog PLL was designed in block leveland tested for different types of jitter and then design of a DCO was started. This document was about the design of a digitally controlled oscillator whichoperates with the center frequency of 2.145 GHz. In the first stage of the projectthe LC tank with NMOS structure was built and tested. In the latter stage the LCtank was optimized by using PMOS structure as negative resistance and eventuallyended up with NMOS and PMOS cross coupled structure. Tuning banks were oneof the main design in this project which plays a key role in locking the system ifthe DCO is placed in an all-digital PLL system. So, three types of tuni

This thesis work addresses semiconductor device technology, characterization and modeling solutions that support the development of future generations of mobile phones, which are able to handle various wireless services in flexible manner. Today’s plurality of high data-rate communication signals requires high linearity and efficiency of the wireless transceiver. Currently handsets follow a multi-path implementation to integrate the various communication services. To handle the rapidly increasing complexity related to the growing number of communication standards, an adaptive RF front-end, able to change operating frequency, bandwidth, as well as output power, would be very advantageous. To reach this goal, new enabling tunable passive components are required that do not introduce any significant signal losses or signal quality degradation. In view of this, conventional varactor diodes disqualify themselves for linear RF applications due to their inherent non-linearity. In this thesis, novel varactor topologies in combination with specific doping profiles have been proposed that can overcome these limitations. Furthermore a dedicated double-sided contacting technology, namely silicon-on-glass, is introduced to manufacture these novel devices, which are subsequently characterized by newly developed dedicated methods. The usefulness of the proposed approach is demonstrated through several circuits, including adaptive matching networks, filters and phase shifters. Finally the linearity of silicon and gallium-arsenide bipolar transistors is investigated, exposing their fundamentally different linearity properties. Through careful characterization, not only the (dis)advantages of some technologies are highlighted, but also new directions and dedicated optimization techniques are provided to support the development of linear transmitters for future 3G/4G/LTE communication applications., Microelectronics, Electrical Engineering, Mathematics and Computer Science

In der vorliegenden Arbeit wird ein Mikroresonator für die kernmagnetische Resonanzspektroskopie kleinster Probenvolumen entwickelt. Der Resonator besteht aus einem Mikrodetektor und einer elektrisch steuerbaren Kapazität für den Resonanzabgleich. Beide Bauteile sind speziell an die Anforderungen des Messverfahrens angepasst. Der Mikrodetektor, welcher die Funktion der Erregung der Kernspins und die Detektion des Messsignals erfüllt, weist aufgrund seiner besonderen Geometrie ein weitgehend homogenes statisches Magnetfeld im Bereich des Probenvolumens auf. Daraus resultieren eine Verbesserung der spektralen Auflösung und eine Steigerung der Empfindlichkeit. Die elektrisch steuerbare Kapazität weist eine hohe elektrische Güte und eine hohe Spannungsfestigkeit auf, wodurch die Verwendung von hohen Pulsleistungen möglich ist. Der Nachweis der Funktionalität des Systems erfolgt durch die Integration des Mikroresonators in einen Probenkopf, welcher zur Messung von Test- und Referenzsignalen eingesetzt wird. Anhand der Messwerte wird gezeigt, dass die neue Entwicklung eine sehr hohe Empfindlichkeit und eine deutlich höhere spektrale Auflösung als andere Detektorsysteme dieser Art aufweist und somit besonders gut für die Messung von sehr kleinen Probenvolumen geeignet ist., The thesis describes the development of a micro resonator for nuclear magnetic resonance (NMR) spectroscopy of very small sample volumes. The resonator consists of a microcoil and an electrically adjustable capacitance for resonance tuning. Both components are specially designed for the purpose of NMR. The microcoil excites the nuclear spins and detects the measurement signal. Due to the special cylindrical geometry, the detector provides a very homogenous spatial distribution of the static magnetic field at the location of the sample. This leads to improved spectral resolution and increased sensitivity. The electrically adjustable capacitance provides a high quality factor and high voltage stability. Hence, short excitation pulses with high bandwidth can be applied. The components are integrated into a specially designed probe. The functionality of the system is demonstrated by test and reference measurements. The measurement results verify the high sensitivity and the high spectral resolution. Hence, the system is applicable and well suited for NMR measurements of small sample volumes.

Doping technologies for formation of ultrashallow and highly-doped p+ junctions are continuously demanded to face the challenges in front-end processing that have emerged due to the aggressive downscaling of vertical dimensions for future semiconductor devices. As an alternative to implantations, current solutions are based on in-situ boron (B) doping during Si/SiGe chemical vapor deposition (CVD) by using diborane (B2H6) as the dopant gas. In this context, a few studies have demonstrated p+-like doping behavior of n-type (100)-oriented Si surfaces after exposure solely to B2H6 in an oxygen-free atmosphere without any extra addition of silane-based sources. As illustrated in Chapter 1, this doping process relies on the thermal decomposition of the source gas, so that the available boron atoms may stick to the surface, chemically react with silicon atoms, and diffuse into the substrate. Contrary to other doping impurities, by appropriately varying the source gas parameters and the exposure time, the reaction kinetics can also cause the boron density at the silicon surface to significantly increase beyond the solid solubility in Si at the given processing temperature. Thus, a boron layer can be formed. However, this property has not been explored so far with respect to reliable integration in Si-based device technologies, since boron segregation has been commonly addressed as a drawback of this doping method. This thesis presents the characterization of nanometer-thick B-layers formed during exposure to diborane in a commercially available CVD system at either atmospheric or reduced pressures down to 500C by using B2H6 at high concentrations. The process, as described in Chapter 2, substantially differs from previous approaches both with respect to the low temperature used and the gas exposure conditions. The former is generally very attractive for versatile use of a doping technology, while the excessive B adsorption intentionally promoted on the Si surface, i.e. the, Microelectronics & Computer Engineering, Electrical Engineering, Mathematics and Computer Science

The thesis describes development and application of coupled resonant coil sensors, which is of growing interest for remote monitoring applications. An interrogation technique, which improves the accuracy and interrogation range of coupled resonant coil sensors, is introduced. The method uses time-domain gating to produce measurements that are dominated by the response of the sensor coil and are immune to surrounding object interference. For application in structural health monitoring a low cost embeddable coupled coil sensor, which is able to monitor the corrosion potential of reinforcement steel is presented. Results of an accelerated corrosion test using the sensor indicate that corrosion potential can be monitored with a resolution less than 10 mV and a sensitivity of 0.76 kHz/mV. The last part describes a coupled-coil pH sensor based on pH electrode potential measurement. A linear response over a 4 to 10 pH dynamic range and 50 kHz/pH sensitivity are achieved with a 0.1 pH resolution and 30 s response time.

This paper presents a type of two-pole microstrip bandpass filter with one reconfigurable transmission zero. The couplings between the resonators and the non-resonant nodes are used to generate the transmission zero. The desired tunability of the transmission zero is realized by changing the center frequencies of the two resonators. In the practical designs, varactors are employed to shift the center frequencies of the resonant node. To verify the working principles, filters implementing the proposed topology are fabricated and measured. Good results have been obtained. © 2006 EuMA.

Three-and six-diode integral oscillator modules were considered the designs of which ensure the possibility of electric tuning of both the output signal and the bandwidth of varactor frequency tuning. In addition, the six-diode oscillator module simultaneously ensures both the efficient combining of power of diodes with negative resistance at the level of semiconductor chips. Such oscillator modules are designed for operation in the centimeter and millimeter wavelength bands. The results of experimental investigations of prototypes of integral multidiode IMPATT-oscillator modules manufactured with due regard for the results of mathematical simulation were presented.

A novel GaN-based Double-Channel Metal-Semiconductor-Metal Configuration Planar Inter-Digitated varactor fabricated with HEMT compatible process is presented. Our varactors achieved high Q-factor, wide tuning range and high minimun Q-factor (Qmin). The double-channel heterostructure extends the useful high Q-factor capacitance tuning range of the varactors. The operation of the varactor is explained by a physical equivalent circuit, in which the whole changing trend of extracted Q-factors over bias voltage and extracted resistance can be explained. The measurement results of the novel double-channel varactors are compared with the varactors facbricated on single channel heterostructure in order to show its superior performances. © 2005 IEEE.

The present work is dedicated to the development of high performance integrated circuits for wireless communications, by acting of three different levels: technologies, devices, and circuits. Silicon-on-Insulator (SOI) CMOS technology is used in the frame of this work. Micromachining technologies are also investigated for the fabrication of three-dimensional tunable capacitors. The reliability of micromachined thin-film devices is improved by the coating of silanes in both liquid- and vapor-phases. Since in telecommunication applications, distortion is responsible for the generation of spurious frequency bands, the linearity behavior of different SOI transistors is analyzed. The validity range of the existing low-frequency nonlinear characterization methods is discussed. New simple techniques valid at both low- and high-frequencies, are provided, based on the integral function method and on the Volterra series. Finally, the design of a crucial nonlinear circuit, the voltage-controlled oscillator, is introduced. The describing function formalism is used to evaluate the oscillation amplitude and is embedded in a design methodology. The frequency tuning by SOI varactors is analyzed in both small- and large-signal regimes., (FSA 3)--UCL, 2004

Na0.5K0.5NbO3(NKN) thin films have been prepared on Pt80Ir20, SiO2/Si, and Ta2O5/Si substrates for ferroelectric non-volatile memory applications. Ferroelectric hysteresis loops for Au/NKN/Pt80Ir20 vertical capacitor yielded remnant polarization of 12 muC/cm(2) and coercive field similar to20 kV/cm. Significant flat-band voltage V-FB shifts with buffer layer thickness in Au/NKN/SiO2/Si structures have been attributed to the intermixing between Na and K alkali ions and SiO2 layer. On the other hand, Au/NKN/Ta2O5/Si structure exhibited wide memory window without significant V-FB deviations, low leakage currents, and rather long retention time at zero bias., QC 20100525

This paper presents a new CMOS compatible SOI gated varactor for use in rf ICs, With its additional third terminal, the device,offers an exceptional large tuning range and a good quality factor. The result of the MEDICI simulation of the structure of the varactor has been confirmed with measured data. A VCO circuit that can potentially exploits the three-terminal property is also reported.