Behavioral modeling and simulation of a parametric power amplifier

Gray, Blake; Kenney, J.S.; Melville, Robert

doi:10.1109/mwsym.2009.5165961

Cited by 8 publications

(2 citation statements)

References 5 publications

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“…In contrast to transistor-based lownoise amplifiers that require a wired direct current (DC) power source [22], parametric amplifiers can be powered wirelessly with an externally applied radio frequency (RF) field such that the internally detected signal is amplified in situ before it is wirelessly transmitted by an external detector. This so called 'pumping signal' amplifies the weak MR signal at the MR frequency ω 1 as well as the signals at the difference frequency 'idler' between the pumping signal and the MR input signal ω 2 = ω 3 − ω 1 [23], [24]. During this process, energy is supplied to the circuit through capacitance variation of a PN-junction diode that amplifies both the signal (ω 1 ) and the idler (ω 2 ) frequencies.…”

Section: A Working Principle Of the Parametric Amplifier (Paramp)mentioning

confidence: 99%

Signal Sensitivity Enhancement of High-Spatial-Resolution MR Imaging With a Concatenated Cylindrical Parametric RF-Resonator

2019

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Phased array MRI coils can increase sensitivity of superficial tissues owing to their proximity to the detection region. Deep-lying tissues, on the other hand, do not benefit to the same degree. Here we investigate the use of a localized cylindrically symmetric quadruple frequency resonator concatenated with a double frequency resonator to increase the longitudinal field-of-view (FOV) without compromising the spatial-resolution and detection sensitivity. These concatenated array coils work on the principle of a parametric amplification to provide wireless amplification of the locally detected NMR signal prior to inductively coupling the coil to an external pick-up loop with connection to the system receiver. When both the detectors are activated together, the effective range of both overlay to create a larger FOV enabling better identification of detectable regions. Furthermore, the in-vivo test of the concatenated detector provides a worst-case 5-fold SNR gain in regions separated from the cylindrical surface larger than its own diameter. This proposed approach of concatenated detector realization can be individually activated and manipulated to enlarge the sensitivity-enhanced region without sacrificing their individual performance. Compared to double frequency detectors, quadruple frequency detectors offer more flexibility in the choice of detector dimension, enabling multi-element concatenation over an extended FOV.

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Section: A Working Principle Of the Parametric Amplifier (Paramp)mentioning

confidence: 99%

Signal Sensitivity Enhancement of High-Spatial-Resolution MR Imaging With a Concatenated Cylindrical Parametric RF-Resonator

2019

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“…At lower frequencies, researchers have modelled the transducer gain, gain compression point, power efficiency, stability, as well as linearity of discrete parametric circuits, including degenerate parametric amplifiers and upconverters [55]- [68], however linearity analyses of CMOS-based continuoustime parametric upconverters in the millimeter-wave range remain scarce.…”

Section: Introductionmentioning

confidence: 99%

Linearity Analysis of CMOS Parametric Upconverters

2020

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This paper applies a conversion matrix approach to the linearity analysis of a varactorbased 36-GHz CMOS parametric upconverter. The nonlinear model of the upconverter is explained and derived. The comparison between the measurements, simulations, and theoretical calculation is presented to show excellent agreements: 0.5-and 1.5-dB differences in conversion gains for lower-sideband and uppersideband upconversion, and less than 2.9-dB in both IIP 2 and IIP 3 when converting a 1-GHz signal to 36-GHz output.

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