Active Shielding of RF Traps

Motivation: Baluns and RF traps are resonant structures and coupling among each other, as well as to receive and transmit coils must be avoided. This is a particular challenge for the efficient and compact class of wound inductor traps. Goal(s): Wound inductor trap that is isolated from external fields, does not require metallic shielding surfaces and can be wound compactly also for cables with limited bending radius. Approach: Employing the method of active shielding known from gradient coil design to RF trap inductors. Results: RF traps with shielding properties comparable to metal sheath shielded versions with very low eddy current profile. Impact: Compact and efficient RF traps can help to design better and safer RF coils. Requiring no metal sheath for shielding of the trap can help to reduce gradient-switching-induced vibrations and heating.