Planar Microcoils

Figure 7.3.1.4 Microfabricated RF coils (a) photograph of a 325 pm-diameter solenoidal microcoil fabricated by microcontact printing. Adapted by permission of the American Institute of Physics, from Rogers, J. A., Jackman, R. J., Whitesides, G. M., Olson, D. L. and Sweedler, J. V., Appl. Phys. Lett., 1997, 70, 2464. (b) Scanning electron micrograph of a planar microcoil with an o.d. of 200 pm and an i.d. of 60 pm...

Schematics of a micromachined NMR probe. The probe consists of a multi-turn electroplated planar microcoil integrated on a glass substrate with etched microfluidic channels for sample containment. The coil has typical dimensions of 2 mm or less, with sample-containment capability ranging from a few nanoliters to 1 [lL, depending on coil size. As a reference, the coil lies in the yz plane with the static magnetic field B0 along the z-axis [797]. Reprinted with permission from Elsevier Science.

A planar microcoil-based probe was fabricated on a glass chip for NMR measurement (see Figure 7.47). The H NMR spectrum of sucrose in D20 was shown in Figure 7.48. The noise is mainly due to the thermal fluctuations generated by the series resistance of the coil (e.g., 1 2). To reduce the channel wall thickness... 

Fit . 93.2 Special surface coils, (a) Electron micrograph of a planar microcoil. Adapted from fWebI J with permission from Elsevier Science, (b) Drawing of a semitoroidal coil [Assl J. 

A. Beyzavi and N.T. Nguyen One-dimensional actuation of a ferrofluid droplet by planar microcoils. Journal of Physics D-Applied Physics 42, (2009)... 

R. S. Popovic, An NMR magnetometer with planar microcoils and integrated electronics for signal detection and amplification. Sens. Actuators A 1998, 67, 18-23. 

Figure 7.2 Electron micrograph of the first planar microcoil. The o.d. is 200pm. Reproduced with permission from [25].

Integration of biaxial planar gradient coils and an RF microcoil for NMR flow imaging, Meas. Sci. Technol. 2005,16, 505-512. 

Figure 7.3 Picture of a micromachined planar NMR probe. The glass chip has a size of 16x8 mm The visible microfluidic channels have a width of approximately 170pm. The pointed microcoil has an i.d. of 500pm and an observed volumeofBO nL.The sample is injected...

Having developed microcoils on a substrate, it is only one step further to integrate more than one microfluidic channel in the substrate on which the planar coil is placed, for example in order to study reaction kinetics. Developments in silicon and glass microfabrication technology have increased rapidly and integration of different chemical unit processes can be made easier by the use of modern microfabrication. 

Figure 7.8 NMR glass chip with planar copper microcoil. Chipsize, 1 X 1.5 cm channel width underneath coil, 500 Xm [39].

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