Radio-Frequency Power Harvest And Remote Clock Frequency Calibration Of Passive Wireless Microsystems

This thesis deals with radio frequency power harvest and remote calibration of system clock of passive wireless microsystems. The proposed method of RF power harvesting utilizes a step-up transformer inserted between the antenna and voltage multiplier of passive wireless microsystems to perform both impedance transformation for power matching and voltage amplification prior to rectification. The series resistance of the primary winding is minimized while in the secondary winding, the shunt capacitive losses are minimized. The detailed analysis of the proposed method and simulation results from Spectre of Cadence Design Systems are presented. The proposed power-matching and gain -boosting network, together with voltage multipliers, has been implemented in TSMC-0.18..m 1.8V6-meatl CMOS technology with thick metal options. For the purpose of comparison, a LC power-matching and gain-boosting network with the identical voltage multiplier has also been implemented on the same chip. Measurement results demonstrate that the proposed transformer power-matching and gain-boosting technique greatly improves the power sensitivity and efficiency as compared with widely used LC matching approaches. The proposed calibration method adjusts the frequency of the local oscillator of passive UHF wireless transponders to the desired values using an injection-locked phase-locked loop (IL-PLL). A new relaxation oscillator whose oscillation frequency is less sensitive to supply voltage fluctuation is also proposed. The power consumption of the proposed IL-PLL is minimized by operating it the sub-threshold. A detailed analysis of non-harmonic injection locking of relaxation oscillators including locking and pulling dynamics is presented. A new integrating feedback is proposed to increase the lock range and hold the locked frequency in the absence of the injection signal. The proposed ILL-PLL has been fabricated in TSMC-0.18.

Radio-Frequency Power Harvest And Remote Clock Frequency Calibration Of Passive Wireless Microsystems

This thesis deals with radio frequency power harvest and remote calibration of system clock of passive wireless microsystems. The proposed method of RF power harvesting utilizes a step-up transformer inserted between the antenna and voltage multiplier of passive wireless microsystems to perform both impedance transformation for power matching and voltage amplification prior to rectification. The series resistance of the primary winding is minimized while in the secondary winding, the shunt capacitive losses are minimized. The detailed analysis of the proposed method and simulation results from Spectre of Cadence Design Systems are presented. The proposed power-matching and gain -boosting network, together with voltage multipliers, has been implemented in TSMC-0.18..m 1.8V6-meatl CMOS technology with thick metal options. For the purpose of comparison, a LC power-matching and gain-boosting network with the identical voltage multiplier has also been implemented on the same chip. Measurement results demonstrate that the proposed transformer power-matching and gain-boosting technique greatly improves the power sensitivity and efficiency as compared with widely used LC matching approaches. The proposed calibration method adjusts the frequency of the local oscillator of passive UHF wireless transponders to the desired values using an injection-locked phase-locked loop (IL-PLL). A new relaxation oscillator whose oscillation frequency is less sensitive to supply voltage fluctuation is also proposed. The power consumption of the proposed IL-PLL is minimized by operating it the sub-threshold. A detailed analysis of non-harmonic injection locking of relaxation oscillators including locking and pulling dynamics is presented. A new integrating feedback is proposed to increase the lock range and hold the locked frequency in the absence of the injection signal. The proposed ILL-PLL has been fabricated in TSMC-0.18.

Spectroscopic evaluation of vibrational temperature and electron density in reduced pressure radio frequency nitrogen plasma

The optical emission spectroscopy technique is used to determine the vibrational temperature of the second positive band system,$$ N_{2} (C,\upsilon^{^{\prime}} - B,\upsilon^{^{\prime\prime}}$$ N 2 ( C , υ ′ - B , υ ″ ) in the wavelength range 367.1–380.5 nm by using the line-ratio and Boltzmann plot methods. The electron temperature is evaluated from the intensity ratio of the selected molecular bands corresponding to $$N_{2}^{ + } (B,\upsilon - X, \upsilon^{^{\prime}} , $$ N 2 + ( B , υ - X , υ ′ , 391.44 nm), and, $$N_{2} (C,\upsilon^{^{\prime}} - B,\upsilon^{^{\prime\prime}}$$ N 2 ( C , υ ′ - B , υ ″ , 375.4 nm) transitions, respectively. The selected bands have a different threshold of excitation energies and thus serve as a sensitive indicator of the electron energy distribution function (EEDF). The electron density has been determined from the intensity ratio of the molecular transitions corresponding to $$N_{2}^{ + } (B,\upsilon - X, \upsilon^{^{\prime}} , $$ N 2 + ( B , υ - X , υ ′ , 391.44 nm), and, $$ N_{2} (C,\upsilon^{^{\prime}} - B,\upsilon^{^{\prime\prime}}$$ N 2 ( C , υ ′ - B , υ ″ , 380.5 nm) for different levels of pressure and radio frequency power. The results show that the vibrational temperature decreases with increasing nitrogen fill pressure and radio frequency power. However, the electron temperature increases with radio frequency power and reduces with fill pressure. The electron density increases both with nitrogen fill pressure and radio frequency power that attributes to the effective collisional transfer of energy producing electron impact ionization. Plasma parameters show a significant dependence on discharge conditions and can be fine-tuned for specific surface treatments. Article Highlights Spectrum analysis of RF-driven nitrogen plasma for varying discharge conditions Evaluation of vibrational temperature using line-ratio and Boltzmann plot methods Comparison of vibrational temperatures for line-ratio and Boltzmann plot methods Evaluation of electron temperature and density using the intensity-ratio of bands Correlation of temperature and density with varying fill pressure and RF power