Browse Prior Art Database

Dielectric Board Capacitors For RF Coil

IP.com Disclosure Number: IPCOM000177956D
Publication Date: 2009-Jan-12
Document File: 3 page(s) / 19K

Publishing Venue

The IP.com Prior Art Database

Abstract

The invention provides dielectric board capacitors for RF coils. In an embodiment, a dielectric board material with copper cladding (or any other high electrical conductivity material) on both sides of the board material is disclosed. The use of such dielectric capacitors for a RF coil design will reduce the local electric field significantly thereby in turn reducing the localized SAR to a great extent. In another embodiment, such dielectric capacitors boards can have cutouts or slits or some other eddy current reducing patterns/techniques etched on them to reduce the acoustic noise vibration in the MR system.

This text was extracted from a Microsoft Word document.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 52% of the total text.

Dielectric Board Capacitors For RF Coil

PROBLEM: High voltage chip/disc capacitors are used in designing RF coils especially at the end-ring locations or in the rungs of the birdcage coil. These capacitors are very expensive and extremely small in size. From RF performance point of view, using such capacitors produce highly localized E-field which in-turn produces high local SAR, which is a concern for patient safety and comfort. Also using nearly 250 such chip capacitors in a RF coil (particularly body coil) makes the coil very expensive.

SOLUTION: The design proposed here is to use a dielectric board material with copper cladding (or any other high electrical conductivity material) on both sides of the board material. This dielectric board is usually made of a material with certain dielectric constant, high dielectric break down voltage, extremely low dielectric loss and so on. These dielectric board capacitors are made of thin board materials, which make the dimensions of dielectric capacitors much bigger than chip or the disc capacitors. The use of such dielectric capacitors for a RF coil design will reduce the local electric field significantly thereby in turn reducing the localized SAR to a great extent. Also, using such capacitors will distribute the RF current uniformly over the entire width of the capacitor. In addition to this it will greatly enhance the patient safety and comfort. Such capacitor designs can easily be implemented in any type of RF coil design such as Birdcage, TEM, Micro-strip and so on. An example of the dielectric capacitor is shown in Figures 1 (top view) and 2 (side view) where blue color represents the dielectric material and the green color represents the copper conductor.

Moreover such dielectric capacito...