Design and numerical analysis of a Birdcage resonator without lumped capacitors

To handle the high, continuously transmitted power, a birdcage resonator without lumped capacitors is created. The discussed design consists of eight partially overlapping sheets of copper on polyimide. The resulting structure (polyimide substrate between two copper layers) creates the capacitive part of the resonator, without the need for any added capacity. The fine-tuning of the resonance frequency by the change in the area of the overlapping part is described. Finally, the frequency of the fundamental resonance mode is adjusted to 300 MHz.