PURPOSE Magnetic resonance imaging (MRI) of rodents can be expected to be a growing application, particularly when translatory imaging research "from mouse to man" is envisioned. 7 T high-field human whole-body MR systems provide a powerful platform for high-resolution small animal imaging. For achieving adequate spatial resolution, dedicated radiofrequency coils have to be designed to provide ...

Parameter variability due to process, voltage, and temperature variations (PVT) in the contemporary submicron CMOS chips makes RF circuit design risky unless proper calibration procedures are applied. They usually require careful on-chip measurements by RF sensors that can be used to compensate for the possible impairments in specs such as gain or gain mismatch which is critical e.g. in IQ setu...

INTRODUCTION: In this contribution radio-frequency cardiography (rf-CG) is proposed as a method to derive physiological cardiac information non-invasively and without the need to attach an electric to the human skin. Information about the cardiac cycle is in particular desired during cardiac MRI in order to reduce artifacts related to cardiac wall motion. In the past, several approaches were su...

Introduction Due to its high imaging speed and SNR efficiency, spoiled gradient echo imaging plays an important role in many quantitative MR methods. For example, a variable flip angle (VFA) method [1] is now widely used for in vivo T1 mapping due to its time efficiency and large 3D anatomical coverage. Recently, an actual flipangle imaging (AFI) technique [2], which utilizes two interleaved sp...

RF pulse designs for signal recovery in T ∗ 2 -weighted functional magnetic resonance imaging

High precision phase measurement is important for many areas of accelerator operation. In a heterodyne digital receiver, one source of phase error is the thermal variation of the input stage. We have developed a technique to calibrate this drift. A CW calibration signal is sent through the same components together with the RF signal to measure and compensate the component drift. At intermediate...

In this article, the performance of a self-organizing migration algorithm (SOMA), a new stochastic optimization algorithm, has been compared with simulated annealing (SA) and differential evolution (DE) for an engineering application. This application is the automated deduction of 14 Fourier terms in a radio-frequency (RF) waveform to tune a Langmuir probe. Langmuir probes are diagnostic tools ...

UMTS transmitters in handsets, based on WCDMA, have to fulfill contradicting requirements. On the one hand, they should operate in a highly power efficient way because battery lifetime is a major consideration for handsets. For this purpose, the application of switchedmode RF power amplifiers seems to be advantageous. On the other hand, the spectral efficiency of the transmitted signal has to b...

This paper presents a systematic design methodology for impedance matching circuits of an RF energy harvester to maximize the harvested energy for a range of input power levels with known distribution. Design of input matching networks for RF rectifier differs from those for traditional RF circuits such as low-noise amplifier because the transistors in the RF rectifiers operate in different reg...

the mixed-signal circuits with both analog and digital blocks on a single chip have wide applications in communication and rf circuits. integrating these two blocks can cause serious problems especially in applications requiring fast digital circuits and high performance analog blocks. fast switching in digital blocks generates a noise which can be introduced to analog circuits by the common su...