Field-Simulation Based Engineering of RF Antenna Probes with Non-Uniform Substrates for High-Field Magnetic Resonance Imaging Systems
Keywords:
High-field MRI systems, magnetic field uniformity, patch antenna, RF probeAbstract
It is proposed to replace RF volume coils in high-field Magnetic Resonance Imaging (MRI) scanners by a microstrip patch antenna system. The performed computational studies have demonstrated an opportunity to form extended 3D volumes of homogenous RF magnetic fields by using a system of placed vis-à-vis two patch antennas. In order to control antenna dimensions and homogeneity of antenna near fields, the substrates of antennas have been engineered by appropriate patterning of high permittivity dielectric inserts. A variety of antennas with engineered substrates responding at 600 MHz for application in 14T MRI scanners have been designed, and the homogeneity of magnetic fields achieved inside the antenna system has been demonstrated.
Downloads
References
Y. Hyoungsuk, G. Anand, and J. T. Vaughan, “A method to control non-uniformity RF Bl field for high field magnetic resonance imaging,” IEEE MTT-S Int. Microwave Symp. Dig., Anaheim, CA, pp. 752-755, May 2010.
J. T. Vaughan, G. Adriany, C. J. Snyder, J. Tian, T. Thiel, L. Bolinger, H. Liu, L. DelaBarre, and K. Ugurbil, “Efficient high-frequency body coil for high-field MRI,” Magnetic Resonance in Medicine, 52, pp. 851-859, Sep. 2004.
J. Hoffmann, J. Budde, G. Shajan, and R. Pohmann, “Slice-selective B1 phase shimming at 9.4 T,” Proc. Int. Soc. Mag. Reson. Med., 18, Stockholm, Sweden, pp. 1470, 2010.
G. Shajan, J. Hoffmann, D. Z. Balla, D. K. Deelchand, K. Scheffler, and R. Pohmann, “Rat brain MRI at 16.4T using a capacitively tunable patch antenna in combination with a receive array,” NMR in Biomedicine, vol. 25, no. 10, pp. 1170- 1176, 2012.
J. Hoffmann, G. Shajan, J. Budde, K. Scheffler, and R. Pohmann, “Human brain imaging at 9.4 T using a tunable patch antenna for transmission,” Magnetic Resonance in Medicine, 69, pp. 1494- 1500, 2013.
H. A. Wheeler, “Transmission-line properties of a strip on a dielectric sheet on a plane,” IEEE Tran. Microwave Theory Tech., vol. MTT-25, pp. 631- 647, Aug. 1977.
T. Reynalda, A. Munir, and E. Bharata, “Characterization of 4x4 high gain microstrip array antenna for 3.3GHz WiMAX application,” IEEE TSSA, 6th Int. Conference, Bali, Indonesia, pp. 215- 218, Oct. 2011.
E. Semouchkina, A. Baker, G. Semouchkin, T. Kerr, and M. Lanagan, “Wearable patch antenna for voice communications with substrate composed of high contrast dielectrics,” IEEE APS Int. Symp., Honolulu, HI, pp. 4188-4191, June 2007.
E. Semouchkina, J. Scholz, S. Perini, G. B. Semouchkin, M. Lanagan, R. Haupt, and H. Simonds, “Metamaterials inspired miniaturization of UHF patch antennas with circular polarization,” Microwave and Optical Technology Letters, vol. 53, no. 8, pp. 1938-1943, Aug. 2011.
W. M. Brink, R. F. Remis, and A. G. Webb, “A theoretical approach based on electromagnetic scattering for analyzing dielectric shimming in high-field MRI,” Magnetic Resonance in Medicine, June 2015.
X. Chen, “Analytical path to improved RF field homogeneity for high field MRI,” Ph.D. Thesis, Department of Physics, CASE Western Reserve University, 2009.
J. T. Vaughan, M. Garwood, C. M. Collins, W. Liu, L. DelaBarre, G. Adriany, P. Andersen, H. Merkle, R. Goebel, M. B. Smith, and K. Ugurbil, “7T vs. 4T: RF power, homogeneity, and signal-to-noise comparison in head images,” Magnetic Resonance in Medicine, vol. 46, no. 1, pp. 24-30, Jan. 2001.
