High-speed communication circuits: voltage control oscillators and VCO-derived filters

Voltage Controlled Oscillators (VCO) and filters are the two main topics of focus in this dissertation.;A temperature and process compensated VCO, which is designed to operate at 2 GHz, and whose frequency variation due to incoming data is limited to 1% of its center frequency was presented. The test results show that, without process changes present, the frequency variation due to a temperature change over 0°C to 100°C is around 1.1% of its center frequency. This is a reduction of a factor of 10 when compared to the temperature variation of a conventional VCO.;A new method of designing continuous-time monolithic filters derived from well-known voltage controlled oscillators (VCOs) was introduced. These VCO-derived filters are capable of operating at very high frequencies in standard CMOS processes. Prototype low-pass and band-pass filters designed in a TSMC 0.25 mum process are discussed. Simulation results for the low-pass filter designed for a cutoff frequency of 4.3 GHz show a THD of -40 dB for a 200 mV peak-peak sinusoidal input. The band-pass filter has a resonant frequency programmable from 2.3 GHz to 3.1 GHz, a programmable Q from 3 to 85, and mid-band THD of -40 dB for an 80 mV peak-peak sinusoidal input signal.;A third contribution in this dissertation was the design of a new current mirror with accurate mirror gain for low beta bipolar transistors. High mirror gain accuracy is achieved by using a split-collector transistor to compensate for base currents of the source-coupled

DTMOS-Based 0.4V Ultra Low-Voltage Low-Power VDTA Design and Its Application to EEG Data Processing

In this paper, an ultra low-voltage, ultra low-power voltage differencing transconductance amplifier (VDTA) is proposed. DTMOS (Dynamic Threshold Voltage MOS) transistors are employed in the design to effectively use the ultra low supply voltage. The proposed VDTA is composed of two operational transconductance amplifiers operating in the subthreshold region. Using TSMC 0.18µm process technology parameters with symmetric ±0.2V sup¬ply voltage, the total power consumption of the VDTA block is found as just 5.96 nW when the transconductances have 3.3 kHz, 3 dB bandwidth. The proposed VDTA circuit is then used in a fourth-order double-tuned band-pass filter for processing real EEG data measurements. The filter achieves close to 64 dB dynamic range at 2% THD with a total power consumption of 12.7 nW

Active band-pass filters using twin-tee networks

The primary objective of this thesis was the design and construction of a set of filters to determine the spectral energy density of random signal data in the spectrum from 10 cps to 20 kcps. The statement of the problem placed rather exacting conditions on the cost and performance of the equipment, and these conditions were met to the extent detailed in the following pages. A secondary objective was the investigation of techniques to improve the performance of band-pass active filters using resistive-capacitive feedback networks. This objective was not achieved to the author\u27s satisfaction, although several promising ideas were discovered --Abstract, page ii

Process and Temperature Compensated Wideband Injection Locked Frequency Dividers and their Application to Low-Power 2.4-GHz Frequency Synthesizers

There has been a dramatic increase in wireless awareness among the user community in the past five years. The 2.4-GHz Industrial, Scientific and Medical (ISM) band is being used for a diverse range of applications due to the following reasons. It is the only unlicensed band approved worldwide and it offers more bandwidth and supports higher data rates compared to the 915-MHz ISM band. The power consumption of devices utilizing the 2.4-GHz band is much lower compared to the 5.2-GHz ISM band. Protocols like Bluetooth and Zigbee that utilize the 2.4-GHz ISM band are becoming extremely popular. Bluetooth is an economic wireless solution for short range connectivity between PC, cell phones, PDAs, Laptops etc. The Zigbee protocol is a wireless technology that was developed as an open global standard to address the unique needs of low-cost, lowpower, wireless sensor networks. Wireless sensor networks are becoming ubiquitous, especially after the recent terrorist activities. Sensors are employed in strategic locations for real-time environmental monitoring, where they collect and transmit data frequently to a nearby terminal. The devices operating in this band are usually compact and battery powered. To enhance battery life and avoid the cumbersome task of battery replacement, the devices used should consume extremely low power. Also, to meet the growing demands cost and sized has to be kept low which mandates fully monolithic implementation using low cost process. CMOS process is extremely attractive for such applications because of its low cost and the possibility to integrate baseband and high frequency circuits on the same chip. A fully integrated solution is attractive for low power consumption as it avoids the need for power hungry drivers for driving off-chip components. The transceiver is often the most power hungry block in a wireless communication system. The frequency divider (prescaler) and the voltage controlled oscillator in the transmitter’s frequency synthesizer are among the major sources of power consumption. There have been a number of publications in the past few decades on low-power high-performance VCOs. Therefore this work focuses on prescalers. A class of analog frequency dividers called as Injection-Locked Frequency Dividers (ILFD) was introduced in the recent past as low power frequency division. ILFDs can consume an order of magnitude lower power when compared to conventional flip-flop based dividers. However the range of operation frequency also knows as the locking range is limited. ILFDs can be classified as LC based and Ring based. Though LC based are insensitive to process and temperature variation, they cannot be used for the 2.4-GHz ISM band because of the large size of on-chip inductors at these frequencies. This causes a lot of valuable chip area to be wasted. Ring based ILFDs are compact and provide a low power solution but are extremely sensitive to process and temperature variations. Process and temperature variation can cause ring based ILFD to loose lock in the desired operating band. The goal of this work is to make the ring based ILFDs useful for practical applications. Techniques to extend the locking range of the ILFDs are discussed. A novel and simple compensation technique is devised to compensate the ILFD and keep the locking range tight with process and temperature variations. The proposed ILFD is used in a 2.4-GHz frequency synthesizer that is optimized for fractional-N synthesis. Measurement results supporting the theory are provided

Ring-resonator-based wavelength filters

Microring resonators (MR) represent a class of filters with characteristics very similar to those of Fabry–Perot filters. However, they offer the advantage that the injected and reflected signals are separated in individual waveguides, and in addition, their design does not require any facets or gratings and is thus particularly simple. MRs evolved from the fields of fibre optic ring resonators and micron scale droplets. Their inherently small size (with typical diameters in the range between several to tens of micrometres), their filter characteristics and their potential for being used in complex and flexible configurations make these devices particularly attractive for integrated optics or VLSI photonics applications.\ud MRs for filter applications, delay lines, as add/drop multiplexers, and modulators will be covered in detail in this chapter, while other applications such as in optical sensing, in spectroscopy or for coherent light generation (MR lasers) are outside the scope of this chapter.\ud This chapter focuses primarily on 4-port microrings, while 2-port devices will play a minor role here and are covered in more detail in Chap. 9. The present chapter starts with design considerations, the functional behaviour, and key characteristics of a single microring resonator and continues with the design of cascaded MRs allowing the implementation of higher order filters. Finally, complex devices like add-drop filters, tuneable dispersion compensators, all-optical wavelength converters, and tuneable cross-connects are treated.\u

Disseny i desenvolupament de circuits d'altes prestacions en banda C per a la missió espacial CIMR (Copernicus Imaging Microwave Radiometer) de la ESA

The Arctic is region where deep changes are occurring which have direct repercussions on our weather and climate. CIMR, that stands for Copernicus Imaging Microwave Radiometer, is a mission that will carry a wide-swath conically-scanning multi-frequency microwave radiometer to provide observations of sea-surface temperature, sea-ice concentration and sea-surface salinity, among other sea-ice parameters. In particular, CIMR will highly respond to the requirements from Artic communities. Beyond the immensity of the project itself, SENER Aeroespacial has the chance to be part of such a great mission, together with great organisations such as Thales Alenia Space, OHB Italia and HPS Germany. In fact, SENER Aeroespacial is in charge of designing, prototyping and measuring the equipment that conform the receivers and the calibrators of the radiometer. These equipment are on-board satellite devices, thus a committed design and characterization must be considered regarding space conditions and variability. Through the development of this project, a straightforward explanation of the equipment that take part in the calibration and reception chain is proposed. Moreover, a high-performance design, analysis and prototyping of the receiver chain is proposed. In addition, a complete product development is designed from scratch to the manufacturing and testing of a characteristic prototype ready to be integrated in any RF chain.El Ártico es una región en la que se están produciendo cambios impactantes que repercuten directamente en el tiempo y en el clima. CIMR, cuyas siglas significan Copernicus Imaging Microwave Radiometer, es una misión que consiste en un radiómetro de microondas multifrecuencia de barrido cónico de gran alcance para proporcionar observaciones de la temperatura de la superficie del mar, la concentración de hielo marino y la salinidad de la superficie del mar, entre otros parámetros del hielo marino. En particular, CIMR responderá en gran medida a las necesidades de las múltiples comunidades del Ártico. Más allá de la inmensidad del proyecto en sí, SENER Aeroespacial tiene la oportunidad de formar parte de una misión tan importante, junto con distintivas organizaciones como Thales Alenia Space, OHB Italia y HPS Alemania. De hecho, SENER Aeroespacial se encarga de diseñar, prototipar y medir los equipos que conforman los receptores y los calibradores del radiómetro. Estos equipos son dispositivos embarcados en satélites, por lo que se debe considerar un diseño y caracterización comprometidos con las condiciones y variabilidad del espacio. Mediante el desarrollo de este proyecto se propone una explicación a grandes rasgos de los equipos que intervienen en la cadena de calibración y recepción. Además, se propone un diseño, análisis y prototipado de alto rendimiento de la cadena de recepción. Asimismo, se propone un desarrollo completo del producto desde su inicio hasta la fabricación y prueba de un prototipo característico listo para ser integrado en cualquier cadena de RF.L'Àrtic és una regió on s'estan produint canvis impactants que repercuteixen directament en el temps i el clima. CIMR, que significa Copernicus Imaging Microwave Radiometer, és una missió que consisteix en un radiòmetre de microones multifreqüència d'escombrat cònic de gran abast per proporcionar observacions de la temperatura de la superfície del mar, la concentració de gel marí i la salinitat de la superfície del mar, entre altres paràmetres del gel marí. En particular, CIMR respondrà en gran part a les necessitats de les múltiples comunitats de l'Àrtic. Més enllà de la immensitat del projecte en si, SENER Aeroespacial té l'oportunitat de formar part d'una missió molt important, juntament amb organitzacions distintives com Thales Alenia Space, OHB Italia i HPS Germany. De fet, SENER Aeroespacial s'encarrega de dissenyar, prototipar i mesurar els equips que conformen els receptors i els calibradors del radiòmetre. Aquests equips són dispositius embarcats en satèl·lits, per la qual cosa cal considerar un disseny i caracterització compromesos amb les condicions i la variabilitat de l'espai. Mitjançant el desenvolupament d'aquest projecte, es proposa una explicació a grans trets dels equips que intervenen a la cadena de calibratge i recepció. A més, es proposa un disseny, anàlisi i prototipat d'alt rendiment de la cadena de recepció. Així mateix, es proposa un desenvolupament complet del producte des del seu inici fins a la fabricació i prova d'un prototip característic llest per ser integrat a qualsevol cadena de RF

6 GHz RF CMOS Active Inductor Band Pass Filter Design and Process Variation Detection

A 90nm CMOS active inductor band pass filter with automatic peak detection is demonstrated in this thesis. The active inductor band pass filter has a better performance than the passive band pass filter in on-chip circuit design, due to small area, larger gain and tunable frequency. However, process variation makes the active inductor band pass filter hard to be used widely in many applications. To settle this issue, an automatic voltage peak detector is introduced to detect the process variation direction and hope to be used to control the active inductor band pass filter center frequency and gain. The designed active filter shows center frequency of 6GHz and quality factor (Q) of 31.9. To drive the peak detector, two analog buffers are designed with f-dB over 6GHz, and one has 0dB gain at low frequency region, another one would emphasize 0dB gain on 6GHz. The voltage peak detector can detect the AC input amplitude range from 0.06V to 0.6 and produce a linear output DC voltage of 77.97mV to 726.65mV

RECONFIGURABLE POWER AMPLIFIER WITH TUNABLE INTERSTAGE MATCHING NETWORK USING GaAs MMIC AND SURFACE-MOUNT TECHNOLOGY

As the demand of reconfigurable devices increases, the possibility of exploiting the interstage matching network in a two-stage amplifier to provide center frequency tuning capability is explored. While placement of tuning elements at the input and/or output matching network has some disadvantages, placement of tuning elements in the interstage absorbs the lossy components characteristics into useful attributes. The circuit design methodology includes graphical method to determine the bandpass topology that achieves high Q-contour on the Smith chart thus result in narrow bandwidth. T-section and π-section topologies are used to match reactive terminations provided by the first and second amplifier stages. The design methodology also includes utilization of interstage mismatch loss that decreases as increasing frequency to compensate for amplifier gain roll-off and equalize the gain at different tuning states. In prototype realization, three design configurations are discussed in this thesis: 1) a discrete design for operation between 0.1 – 0.9 GHz with the total layout area of 7.5 mm x 12.5 mm, 2) a partial monolithic design (Quasi-MMIC) for operation between 0.9 – 2.4 GHz that is 25 times smaller layout area compared to the discrete design, and 3) a conceptual design of integrated monolithic reconfigurable PA for operation between 0.9 – 2.4 GHz that is 130 times smaller layout area compared to the discrete design. One variant of the fabricated reconfigurable PA offers advantage of 4-states center frequency tuning from 1.37 GHz to 1.95 GHz with gain of 21.5 dB (+ 0.7 dB). The feasibility of interstage matching network as tuning elements in reconfigurable power amplifier has been explored. The input and output matching networks are fixed while the interstage impedances are varied using electronic switching (discrete SP4T and GaAs FET switches). The discrete design is suited for the operation at low frequency (fo < 1GHz), while monolithic implementation of the tunable interstage matching network is required for higher frequency operation due to size limitation and parasitic effects. The reconfigurable PA using MMIC tuner was designed at higher frequency to possibly cover GSM, CDMA, Bluetooth, and WiMAX frequency (0.9 – 2.4 GHz)

Maximizing fabrication and thermal tolerances of all-silicon FIR wavelength filters

We propose a method to make silicon optical finite impulse response filters tolerant to fabrication (waveguide geometry) and ambient thermal variations. We experimentally demonstrate a Mach-Zehnder interferometer filter with fabrication and thermal tolerance, both separately and together. The fabrication-tolerant device measurements show a 20-fold improved tolerance to systematic waveguide linewidth variations with a wavelength shift of <60 pm/nm linewidth change. The fabrication-and thermal-tolerant device is possible using orthogonal polarizations in the two arms. The fabricated device shows a shift of less than +/- 65 pm/nm and a thermal drift smaller than +/- 15 pm/K over a wavelength range of 40 nm. Simulations show that this concept can be extended to multichannel filters