Strong demands for smaller, cheaper, and multifunction wireless systems have put very stringent requirements on passive devices, such as inductors and capacitors. This is especially true considering the size and weight of most radio frequency (RF) transceivers are mainly due to passives. RF micro-electro-mechanical-systems (MEMS) passives are addressing this issue by offering lower power consumption and losses, higher linearity and quality (<i>Q</i>)-factors, potential for integration and miniaturization, and batch fabrication. These advantages position RF MEMS passives as good candidates to replace conventional passives. Further, they also open an opportunity for using the passives as building blocks for lumped element-based RF circuits (e.g. Flters, couplers, etc.) which could replace the more-bulky distributed-element circuits.<p> This thesis presents the design, simulation, fabrication using the deep X-ray lithography process, and testing of thick-metal RF inductors and their applications to lumped-element low-pass Filter (LPF) circuits. The 70-um tall single-turn loop inductors are structurally compatible to a pre-existing RF MEMS capacitor concept and allow the two device types to be fabricated together. This compatibility issue is crucial if they would be used to construct more complex RF circuits.<p> At a 50-Ohm inductive reactance point, test results show <i>Q</i>-factors of 17- 55, self-resonant frequencies (SRF) exceeding 11 GHz, and nominal inductances of 0.4- 3 nH for 1-loop inductors and <i>Q</i>-factors of 11- 42, SRFs of 4- 22 GHz, and inductances of 0.8- 5.5 nH for 2-loop inductors. Further, test results reveal that high conductivity metals improve the <i>Q</i>-factors, and that low dielectric-constant substrates increase the SRFs.<p> In terms of LPFs, measurements show that they demonstrate the expected third-order Chebyshev response. Two nickel Filters on a quartz glass substrate show a 0.6-dB ripple with 3-dB frequencies (<i>f</i>-3dB) of 6.1 GHz and 11.9 GHz respectively. On an alumina substrate, they exhibit a 1.4-dB ripple with <i>f</i>-3dB of 5.4 GHz and 10.6 GHz respectively. The filters are 203- 285 um tall and feature 6- 6.5 um wide capacitance air gaps. These dimensions are different than the original designs and the filter performances were shown to be somewhat sensitive to these discrepancies. Compared to a distributed approach, the lumped-element implementations led to an area reduction of up to 95%.

Strong demands for smaller, cheaper, and multifunction wireless systems have put very stringent requirements on passive devices, such as inductors and capacitors. This is especially true considering the size and weight of most radio frequency (RF) transceivers are mainly due to passives. RF micro-electro-mechanical-systems (MEMS) passives are addressing this issue by offering lower power consumption and losses, higher linearity and quality (<i>Q</i>)-factors, potential for integration and miniaturization, and batch fabrication. These advantages position RF MEMS passives as good candidates to replace conventional passives. Further, they also open an opportunity for using the passives as building blocks for lumped element-based RF circuits (e.g. Flters, couplers, etc.) which could replace the more-bulky distributed-element circuits.<p> This thesis presents the design, simulation, fabrication using the deep X-ray lithography process, and testing of thick-metal RF inductors and their applications to lumped-element low-pass Filter (LPF) circuits. The 70-um tall single-turn loop inductors are structurally compatible to a pre-existing RF MEMS capacitor concept and allow the two device types to be fabricated together. This compatibility issue is crucial if they would be used to construct more complex RF circuits.<p> At a 50-Ohm inductive reactance point, test results show <i>Q</i>-factors of 17- 55, self-resonant frequencies (SRF) exceeding 11 GHz, and nominal inductances of 0.4- 3 nH for 1-loop inductors and <i>Q</i>-factors of 11- 42, SRFs of 4- 22 GHz, and inductances of 0.8- 5.5 nH for 2-loop inductors. Further, test results reveal that high conductivity metals improve the <i>Q</i>-factors, and that low dielectric-constant substrates increase the SRFs.<p> In terms of LPFs, measurements show that they demonstrate the expected third-order Chebyshev response. Two nickel Filters on a quartz glass substrate show a 0.6-dB ripple with 3-dB frequencies (<i>f</i>-3dB) of 6.1 GHz and 11.9 GHz respectively. On an alumina substrate, they exhibit a 1.4-dB ripple with <i>f</i>-3dB of 5.4 GHz and 10.6 GHz respectively. The filters are 203- 285 um tall and feature 6- 6.5 um wide capacitance air gaps. These dimensions are different than the original designs and the filter performances were shown to be somewhat sensitive to these discrepancies. Compared to a distributed approach, the lumped-element implementations led to an area reduction of up to 95%.

In this thesis, a brand new first-order low pass square root domain filter (SRD filter) based on operational transconductors amplifiers (OTAs) is presented. The SRD filter consists of a translinear filter and two OTAs. We improve Cruz¡¦s SRD filter [15], reduce the number of transconductors from 3 to 2, and replace Class-AB linear transconductors with OTAs. The circuit has the least number of transistors up to date, therefore, the least power consumption and least chip area. The circuit has been fabricated with 0.35£gm CMOS technology. It operates with a supply voltage 1.5V and the biasing current varies from 0.05uA to 15uA. Measurement results show that the cutoff frequency of the filter can be tuned from 250 Hz to 29 kHz when the external capacitance C is 1nF and the cutoff frequency can be tuned from 1.8 kHz to 237kHz when the external capacitance C is 100pF. The total harmonic distortion is 1.03% and 1.01% when the external capacitance C is 1nF and 100pF and the power consumption is 116£gW.

Στην παρούσα διπλωματική ασχοληθήκαμε με την εύρεση του καρδιακού ρυθμού ενός ατόμου με τεχνικές ψηφιακής επεξεργασίας εικόνας στο κοντινό και στο μέσο υπέρυθρο φάσμα. Χρησιμοποιήσαμε μια σειρά από διόδους εκπομπής στο υπέρυθρο φάσμα και μια βιντεοκάμερα με την οποία πήραμε τα προς εξέταση δεδομένα. Στηριζόμαστε στην ιδιότητας της αιμοσφαιρίνης να απορροφά το υπέρυθρο φως ορισμένου μήκους κύματος. Επεξεργαζόμενοι το οπτικό υλικό που προκύπτει από τις μετρήσεις μας με κατάλληλες μεθόδους μπορούμε να πλησιάσουμε στην εύρεση του καρδιακού ρυθμού, μελετώντας τα βιολογικά σήματα και ευρίσκοντας μεθόδους βελτίωσης τους. / -

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<p>In this study, a novel and systematic methodology for the design and optimization of conductor-backed coplanar waveguide (CB-CPW) based low pass filter (LPF) is proposed. The width of the signal trace is continuously varied using a truncated Fourier series, and the adjacent gaps are designed in several types established on a specific optimization setup to obtain predefined electrical characteristics with maximum compactness taking into account physical constraints. Trust-region-reflective algorithm (TRRA), genetic algorithm (GA), and particle swarm optimization algorithm (PSO) are taken into account to minimize the developed bound-constrained non-linear objective function respectively.<br></p><p>All types are programmed and analytically verified in MATLAB. Solutions include design parameters such as the physical length and width of the structure, which will be drawn in AutoCAD later on. Also, the optimized layouts are exported to Ansys High Frequency Structure Simulation (HFSS) software for simulation and validation. Non-uniform CB-CPW LPFs are optimized and simulated over a frequency range of 0-6 GHz with a cutoff frequency of 2 GHz. Simulation results show a good agreement with the analytical ones.<br></p>

<p>Normally the operational amplifier is used as a component in active filter design. The goal for future components in filter design is large bandwith and the use of low supply voltages. The use of current-mode instead of voltage-mode circuits gets a step closer to the required performance. A component that use current as the signal conveying part is the current conveyor. In this report a comparative study between two current conveyor structures of second generation (CCII) is performed. The most suited is later implemented and simulated using the CMOS process AMS.C035. The component is also tested in a continuous-time elliptic low-pass filter of leapfrog type. The filter does not behave as it should. However, better performance can be obtained by redesigning the current conveyor.</p>

Normally the operational amplifier is used as a component in active filter design. The goal for future components in filter design is large bandwith and the use of low supply voltages. The use of current-mode instead of voltage-mode circuits gets a step closer to the required performance. A component that use current as the signal conveying part is the current conveyor. In this report a comparative study between two current conveyor structures of second generation (CCII) is performed. The most suited is later implemented and simulated using the CMOS process AMS.C035. The component is also tested in a continuous-time elliptic low-pass filter of leapfrog type. The filter does not behave as it should. However, better performance can be obtained by redesigning the current conveyor.

Recently, with advances in CMOS process, the RF receiver which is integrated into the SOC chip can effectively reduce production costs. When designing the wireless receiver, one of the most important technologies is to design channel-selection filter. Typically, the design of the channel-selection filter in multi-standard high-frequency will take up a large chip area and higher power consumption. Therefore, in order to reduce the area and power consumption, this thesis designed a low-power OTA and low-pass filter. This thesis presents a multi-mode wireless communication application in the receiver channel selection filter. This filter is designed to use the fifth-order Butterworth low pass filter, the filter range can be used in Bluetooth, cdma2000, wideband CDMA, and IEEE 802.11a/b/g/n wireless LAN. Using floating transistor architecture in the input stage of OTA can effectively increase the THD performance. Using MOS transistors operating in triode region and combined with current multiplier can achieve the voltage-to-current conversion. Using the trans-linear loop can reach a wide tunable range, and the OTA operating in weak inversion region can significantly reduce the transconductance. Implementation is to use the TSMC 0.18£gm CMOS process. Simulation results show that the successful operation of this filter can be between 650 kHz ~ 22MHz frequency range. The filter may have compatibility in different wireless communication applications. 14.5mW to 17.5mW, respectively, is the smallest to the largest power consumption. The supply voltage is 1.2 volts.

Most discrete time filters use Switched Capacitor structures, but Switched capacitor circuits have finite sampling rate and high power consumption. In this paper we use Switched Current structure to increase sampling rate and reduce power consumption. In this paper, we use a Class-AB structure to compose a double sampling third order low-pass filter. In this paper there are two integrator types. Modified backward Euler and modified forward Euler integrators were realized with double sampling technology from the backward Euler and forward Euler integrators. Compared with other circuits, the circuit has low power supply¡Blow power consumption ¡Bhigh sampling speed. We employ HSPICE and MATLAB to simulate and design the circuit. We use TSMC 0.35£gm process to implement this circuit. The power supply is 1.8V, the cut-off frequency is 3.6MHz, the sampling frequency is 72MHz, and the power consumption is 1.303mW.