volume | PIER Journals

Abstract

Quadrature feeding is an essential in magnetic resonance imaging radio frequency (MRI-RF) coils, to improve the homogeneity of the magnetic field of surface coil, the signal to noise ratio (SNR) of the image by a factor of √2 , and to create a circularly polarized magnetic field inside the volume coil. The quadrature feeding is incorporated, using hybrid coupler. However, at 63.87MHz the Larmor frequency of hydrogen proton, corresponding to 1.5 Tesla, the size of the hybrid coupler and other microwave circuits become large. So, to minimize its physical size, a coaxial cable transmission line with lumped capacitive loading has been proposed. The size of the proposed hybrid coupler is reduced by 68%, as compared to the conventional hybrid coupler. The proposed device is then fabricated as a both rigid and flexible structure, which provides isolation (S₄₁) of around 19 dB and a 900phase difference between coupled and the through ports. Both structures provide return loss S₁₁ > -15 dB and coupling at output ports S₂₁, S₃₁ around 3 dB.

1. Yadav, N. S., I. Kochar, T. K. Bhuiya, and R. Harsh, "RF transmit/receive quadrature fed body birdcage coil for a 1.5 T MR system," 2nd International Conference on Electronics, Material Engineering and Nanotechnology (IEMENTech), 1-7, 2018.

2. Kumar, A. and P. A. Bottomley, "Optimized quadrature surface coil designs," MAGMA, Vol. 21, No. 1–2, 41-52, 2008.
doi:10.1007/s10334-007-0090-2

3. Hoult, D. I., C.-N. Chen, and V. J. Sank, "Quadrature detection in the laboratory frame," Magn. Reson. Med., Vol. 1, 339, 1984.
doi:10.1002/mrm.1910010305

4. Pozar, D. M., Microwave Engineering, 333-336, John Wiley & Sons, 2012.

5. Ugle, N., T. K. Bhuiya, R. Dapkar, D. M. Shinde, and S. Bagchi, "Design and comparison of rectangular, square and hexagonal RF coils for 1.5T MRI system," 2018 9th International Conference on Computing, Communication and Networking Technologies (ICCCNT), 1-4, Bangalore, 2018.

6. Myer, D. P., "Radio frequency power amplifiers for NMR and MRI," RF Coils for MRI, Chap. 24, 307, John Wily & Sons, 2012.

7. Sanchez-Soriano, M. A., Y. Quere, V. L. Saux, C. Quendo, and S. Cadiou, "Average power handling capability of microstrip passive circuits considering metal housing and environment conditions," IEEE Transactions on Components, Packaging and Manufacturing Technology, Vol. 4, 1624-1633, 2014.
doi:10.1109/TCPMT.2014.2345100

8. Crnadak, V. and S. Tasic, "VHF quadrature hybrid coupler," 2015 23rd Telecommunications Forum Telfor (TELFOR), 595-598, Belgrade, 2015.

9. Crnadak, V. and S. Tasic, "Improved VHF quadrature hybrid coupler," 2016 24th Telecommunications Forum (TELFOR), 1-4, Belgrade, 2016.

10. Crnadak, V. and S. Tasic, "VHF quadrature hybrid coupler with the crossed strips," 2017 13th International Conference on Advanced Technologies, Systems and Services in Telecommunications (TELSIKS), 335-338, Nis, 2017.
doi:10.1109/TELSKS.2017.8246292

11. Kulkarni, M., A. N. Cheeran, K. P. Ray, and S. S. Kakatkar, "Novel compact implementation of rat-race hybrid coupler using coaxial cable for VHF applications," 2019 TEQIP III Sponsored International Conference on Microwave Integrated Circuits, Photonics and Wireless Networks (IMICPW), 69-71, Tiruchirappalli, India, 2019.

12. Scardelletti, M. C., G. E. Ponchak, and T. M. Weller, "Miniaturized wilkinson power dividers utilizing capacitive loading," IEEE Microwave and Wireless Components Letters, Vol. 12, No. 1, 1531-1309(02)00862-0, Jan. 2002.
doi:10.1109/7260.975717

13. Kakatkar, S. S., P. Irpache, and K. P. Ray, "A compact N-way wilkinson power divider using a novel coaxial cable implementation for VHF band," Progress In Electromagnetic Research Letters, Vol. 62, 49-55, 2016.
doi:10.2528/PIERL16061205

14. Mohamed, E. N., A. G. Sobih, and A. M. El-Tager, "Compact Wilkinson power divider with Inductive loaded microstrip line for harmonics suppression," 2016 IEEE Middle East Conference on Antennas and Propagation (MECAP), 1-4, Dec. 19, 2016.

15. Jung, S.-C., R. Negra, and F. M. Ghannouchi, "A design methodology for miniaturized 3-dB branch line hybrid couplers using distributed capacitors printed in the inner area," IEEE Transaction for Microwave Theory and Techniques, Vol. 56, No. 12, 2950-2953, Dec. 2008.
doi:10.1109/TMTT.2008.2007323

16. Jung, S., R. Negra, and F. M. Ghannouchi, "A miniaturized double-stage 3 dB broadband branch-line hybrid coupler using distributed capacitors," 2009 Asia Pacific Microwave Conference, 1323-1326, Singapore, 2009.

17. Mongia, R. K., I. J. Bahl, P. Bhatia, and J. Hong, RF and Microwave Coupled Line Circuits, 2nd Ed., 225-227, Artech House, Norwood, MA, 2007.

18. Hirota, T., A. Minakawa, and M. Muraguchi, "Reduced-size branch-line and rat-race hybrids for uniplanar MMIC's," IEEE Transaction for Microwave Theory and Techniques, Vol. 38, 270-275, Mar. 1990.
doi:10.1109/22.45344

19., https://www.pasternack.com/images/ProductPDF/RG187A-U.pdf.

20. Karthik, G. and S. Jayanthu, "Quantification of cable deformation using TDR-experiments," European Journal of Electrical Engineering, Vol. 19, No. 3–4, 209-219, 2017.
doi:10.3166/ejee.19.209-219

21. Dowding, C. H., M. B. Su, and K. O'Connor, "Measurement of rock mass deformation with grouted coaxial antenna cables," Rock Mechanics and Rock Engineering, Vol. 22, No. 1, 1-23, 1989.
doi:10.1007/BF01274117

22. Romheld, M. and W. Hartmann, "Impulse current withstand capability of coaxial cables in high current applications," 2008 IEEE International Power Modulators and High-Voltage Conference, 163-166, Las Vegas, NV, 2008.

Mr. Rohit Apurva

Dr. Niraj Yadav

Dr. Tapas Bhuiya

Dr. Rajesh Harsh