Date The final copy of this thesis has been examined by the signatories, and we find that both the content and the form meet acceptable presentation standards of scholarly work in the above mentioned discipline. Phase Noise in Microwave Oscillators and Amplifiers Thesis directed by Professor Zoya Popovi´c This thesis presents analysis and measurements of phase noise in oscilla-tors and amplifiers. Low phase noise is an increasingly important requirement for RF circuit designers. In digital communications systems, close-in phase noise (or phase jitter in the time domain) affects the system bit-error rate. In analog communications systems, close-in phase noise can limit channel band-width and broadband noise reduces the signal-to-noise ratio and the system sensitivity, especially after several repeater stations. In Doppler radar applications , the oscillator phase noise can set the minimum signal level that must be returned by a target in order to be detected. This thesis describes an experimental method for determining additive phase noise of an unmatched transistor in a stable 50 Ω environment. The measured single-sideband phase noise is used to determine the large-signal noise figure of the device. Such characterization is used as input for the design of oscillators and power amplifiers. Next, a design method for voltage controlled oscillators (VCOs) with simultaneous small size, low phase noise, DC power consumption and thermal drift is presented. Design steps to give good prediction of VCO phase noise and power consumption behavior are: (1) measured resonator frequency-iii dependent parameters; (2) transistor additive phase noise/ noise figure characterization ; (3) accurate tuning element model; and (4) bias-dependent model in case of an active load. It is shown that the method can be applied effectively for design of VCOs that meet requirements for challenging applications such as Chip Scale Atomic Clocks (CSAC). The last part of the thesis is investigation of linearity in power amplifiers and its relations to phase noise. When a device is operated in saturation, it is nonlinear. Most communication systems use modulation of both amplitude (Amplitude Modulation, AM) and phase (Phase Modulation, PM) of the carrier signal, eg. Quadrature Amplitude Modulation (QAM). The various nonlinearities of active microwave circuit result, among other effects, in AM to PM conversion. Since phase modulation is related to phase noise, additive phase noise can be expected to be related to linearity. This relationship is explored and analyzed based on extensive load/source pull measurements of output power, adjacent channel power …

Phase noise in microwave oscillators and amplifiers

The second and third generation of MEMS oscillators will target a larger market for compact oscillators in order to meet TCXO and OCXO performance requirements. While silicon-based timing devices are still not as capable as crystal oscillators of undertaking sophisticated tasks , they are getting better, and will eventually replace crystals in many contexts. That will produce further synergies for the industry as mass production becomes cheaper and easier. These days, designers require higher frequencies and low jitter in oscillators, while buyers demand low cost and quick delivery. Timely oscillator options that can deliver the highest desired performance, while minimally compensating design steps are the key to cost-effective solutions. Fortunately, in the ongoing battle to push the limits of technology and lower component costs, oscillator manufacturers continue to close the gap between highlevel performance and cost-effective purchasing, with conventional crystal technology paired with configurable oscillator technology. Like every exciting new technology targeting mass markets and driven by start-ups, confusion or exaggeration are present, but all in all, we believe that MEMS oscillators will follow the successful bulk acoustic wave devices as the second RF MEMS mass product.

Latest Technology, Technological Challenges, and Market Trends for Frequency Generating and Timing Devices [Application Notes]

The aorta, acting as the main conduit through which cardiac output is delivered to the systemic arterial bed, is continuously exposed to high pulsatile pressure and shear stress, making it prone to mechanical injury. It is also more prone to rupture than other vessels, particularly with the development of aneurysmal dilation. Fifty percent of patients who experience a rupture of a aortic aneurysm die before reaching the hospital (Bengtsson & Bergqvist, 1993). The incidence increases with age and has been reported as 6 per 100,000 person-years (Knowles & Kneeshaw, 2004). Aneurysmal degeneration that occurs in the aortic arch is termed a aortic arch aneurysm. Patients who have aortic arch aneurysm have multiple aortic lesions or aneurysmal disease which involves segment of aorta (Crawford et al., 1984). Aortic arch aneurysms represent only 10% of aneurysms of the thoracic aorta and it has higher risk of rupture than other aneurysm (Knowles & Kneeshaw, 2004). Blood flow through the aorta is one of the most complex flow situations found in the cardiovascular system. Blood flow is pulsatile and pressure inside aortic aneurysm is nonuniform. The dynamics interaction between blood flow and wall may influence the wall stress. Computer modeling has made impressive progress in scientific, engineering, biological and medical applications in recent years and it offers the prospect of providing both a better insight into a range of biomechanical problems and improved tools for the design of medical devices and the diagnosis of pathologies. Computational methods such as mathematical modeling methods (Rideout, 1991; Rupnic & Runvovc, 2002; Abdolrazaghi et al., 2008), computational fluid dynamics methods, (Botnar et al., 2000; Shahcheraghi et al., 2002; Morris et al., 2005; Tokuda et al. 2008) loosely coupled methods (Di Mrrtino et al., 2001; Gao et al., 2006abc) have been used to simulate the biomechanical problems in arotic arch and aortic arch aneurysm. The aim of this chapter is to describe the numerical simulation and computer modeling work in aortic arch aneurysm.

/pdf/numerical-simulation-in-aortic-arch-aneurysm-1z746888b7.pdf

Numerical Simulation in Aortic Arch Aneurysm

This paper presents an overview of a VCXO using 622.08MHz fundamental quartz crystal resonator. The quartz crystal blank has an inverted mesa structure, and has been fabricated by the laminated quartz crystal wafer technology. The characteristics of the VCXO are as follows; the frequency pull range is +/-190ppm(control voltage 1.65+/-1.65V), the phase jitter is 150fs-rms(12kHz to 20MHz), and the package size is 7.0times5.0mm

High performance VCXO with 622.08MHz Fundamental Quartz Crystal Resonator

Propagation of thickness-twist waves in a piezoelectric ceramic plate with unattached electrodes.

We have developed a 622 MHz fundamental crystal resonator using composite wafers with an air-gapped electrode. To reduce the mass loading effect of the electrode, we introduced a three layer laminated quartz wafer and an air-gapped electrode. The electrical characteristics of the 622 MHz fundamental crystal resonator have satisfied the target specification by using a new process and structure.

H. Uehara

Papers

622 MHz high frequency fundamental composite crystal resonator with an air-gapped electrode