Design Of Low Phase Noise Oscillator Research Articles

Design of low phase-noise oscillators based on microstrip triple-band bandpass filter using coupled lines resonator

This paper presents new low phase noise oscillators employing a triple-band bandpass filter as a frequency stabilization element into the feedback loop. In addition, using triple-band bandpass filter (TB-BPF); three oscillators can be easily achieved separately, only by changing the length of the transmission line in feedback loop. The oscillators are designed at the spectrum-based quality factor (Qs) peak frequencies of bandpass filter to achieve low phase noise performance. Also, the oscillation frequencies of the oscillators are designed at 3.4, 4.33 and 6.89 GHz, resulting in achieving the simulated phase noise of these oscillators are −166, −154 and −150 dBc/Hz at the 1-MHz offset frequency respectively. The oscillator with 3.4 GHz carrier frequency is fabricated and the measured results show the 10.7 dBm output power and phase noise is −163 dBc/Hz at 1-MHz frequency offset. The figure of merit of the fabricated oscillator at 1 MHz offset frequency is −218.9 dBc/Hz.

Design of Low Phase-Noise Oscillator Based on a Hairpin-Shaped Resonator Using Composite Right/Left-Handed Transmission Line

In this letter, a low phase-noise microwave oscillator based on a hairpin-shaped resonator (HSR) using a composite right/left-handed transmission line (CRLH TL) is proposed. The proposed HSR consists of the conventional transmission line (CTL) and the CRLH TL. In order to obtain the high- Q factor, an electric field is concentrated on the CRLH TL, and then the CRLH TL provides a low loss due to a slow wave effect. The proposed HSR has a very compact size of 0.105 λg ×0.19 λg. An oscillator based on the HSR was designed, fabricated and measured. At the oscillation frequency of 4.95 GHz, the measured phase noise is -120.5 dBc/Hz at 100 kHz offset with 4.93 dBm output power.

Analysis and Design of Low Phase-Noise Oscillators With Nonlinear Resonators

It is known that the dynamics and phase noise of resonator-based self-sustained nonlinear oscillators is affected by the presence of a nonlinear resonator. In fact, it has been shown that resonator nonlinearity can enhance the oscillator phase noise under certain conditions. This paper offers a new formulation and analytical approach to describe the effect of resonator nonlinearity on the phase noise of self-sustained oscillators. The analysis applies properties of stochastic Ito integrals to oscillator's averaged stochastic nonlinear differential equations with periodic steady state solutions. The results offer insight into designing low phase-noise oscillators with nonlinear resonators. We show that for a given nonlinear oscillator topology, there is an optimum power incident on the resonator that minimizes the phase noise. As a proof of concept, the analysis is applied to a 1.5-GHz CMOS oscillator that uses a nonlinear film bulk acoustic resonator (FBAR). A nonlinear model including memory effects for the FBAR is proposed and used in the formulation. At the optimum design point, the oscillator shows measured phase noise of -110 dBc/Hz at 1 kHz, -125 dBc/Hz at 10 kHz, -145 dBc/Hz at 100 kHz, and -160 dBc/Hz at 10-MHz offset frequencies while consuming 40 mW of dc power. This results in 10 fs of timing jitter.

Design of Low Phase-Noise Oscillators and Wideband VCOs in InGaP HBT Technology

A method for design of low phase-noise balanced-Colpitts (BC) fixed-frequency oscillators (FFOs) and wideband voltage-controlled oscillators (VCOs) is presented. Analytical expressions describe how to design an oscillator for best phase noise, given a limited Q factor and a certain active device. The theory needs only two free parameters: the impedance level (Zc) and tapping ratio (n) of the resonator. It is described how to chose ZC and n for low phase noise and large tuning range, respectively. The design method is verified with a low phase-noise FFO and a wideband VCO, both designed in InGaP HBT technology. The BC FFO presents a phase noise of 112 dBc/Hz at 100-kHz offset from a 9.2-GHz carrier. The wideband VCO implemented in the same technology presents a minimum phase noise of 106 dBc/Hz at 100-kHz offset from a 9-GHz carrier. Over the frequency range of 8.4-9.7 GHz, the phase noise is better than 102 dBc/Hz and the output power is 7 0.5 dBm. The wide tuning range, constant output power, and relatively constant and low phase noise are achieved due to double pairs of tuning varactors, one between emitters and one between collectors. To the authors' best knowledge, this type of double-tuned BC VCO topology has not been previously published.

Measuring Transistor Large-Signal Noise Figure for Low-Power and Low Phase-Noise Oscillator Design

This paper presents an experimental method for determining additive phase noise of an unmatched transistor in a stable 50-Omega environment. The measured single-sideband phase noise is used to determine the large-signal noise figure of the device. From the Leeson-Cutler formula and a known oscillator circuit with the characterized transistor, the phase noise of the oscillator can be predicted. The method is applied to characterization of several bipolar devices around 3.4 GHz, the frequency of interest for miniature rubidium-based atomic clock voltage-controlled oscillators.

High-<tex>$Q$</tex>Active Resonators Using Amplifiers and Their Applications to Low Phase-Noise Free-Running and Voltage-Controlled Oscillators

This paper presents a new technique to design high-Q active resonators. The active resonators are then used in the design of low phase-noise oscillators. The proposed new technique uses an amplifier to generate a negative resistance, which compensates for the resonator losses and increases the Q factor. The active resonator using this technique shows a high loaded Q factor of 548.62 from measurement at the fixed 10-GHz resonant frequency. Considerations to design a voltage tunable active resonator is given and measurements show that the loaded Q factors exceed 500 with a 120-MHz tuning range. A low phase-noise free-running and voltage-controlled oscillator (VCO) were designed as an application of the proposed active resonators. The phase noise of the free-running oscillator using the active resonator is -114.36 dBc/Hz at 100-kHz offset, which is 14 dB lower than the phase noise of the passive resonator oscillator. In the case of a VCO using the active resonator, the phase-noise performance is below -110 dBc/Hz over the whole tuning range, which is lower 13 dB compared to the passive resonator VCO. The total dc power consumptions are approximately 500 mW.