Total active reflection coefficient

In computation of radiation performance of multi-port antennas especially in multiple-input multiple-output (MIMO) antenna systems total active reflection coefficient, TARC, relates the total incident power to the radiated power. The total active reflection coefficient (TARC) is the square root of the sum of all incident powers at the ports minus radiated power, divided by the sum of all incident powers at the ports of an N-port antenna. The TARC is a function of frequency. With this definition we can characterize the multi-port antenna’s frequency bandwidth and radiation performance. TARC can be computed directly from the scattering matrix for different excitations.

$\Gamma _{a}^{t}={\frac {\sqrt {\sum _{i=1}^{N}|b_{i}|^{2}}}{\sqrt {\sum _{i=1}^{N}|a_{i}|^{2}}}}.$

where: $[b]=[S][a].$ $[S]$ is the antenna's scattering matrix, $[a]$ is the excitation vector, and $[b]$ represents the scattered vector. The TARC is a real number between zero and one. When the value of the TARC is equal to zero, all the delivered power is radiated and when it is equal to one, all the delivered power is either reflected back to sources or goes to the other ports.

The relation between the TARC and the radiated power described above only holds under the assumption of lossless antennas. For lossy antennas, the term accepted power should be used instead of radiated power.

References

• Majid Manteghi ; Yahya Rahmat-Samii (22–27 June 2003). "Broadband characterization of the total active reflection coefficient of multiport antennas". IEEE Antennas and Propagation Society International Symposium. 3: 20–23.{{cite journal}}: CS1 maint: multiple names: authors list (link)
• Majid Manteghi ; Yahya Rahmat-Samii (January 2005). "Multiport characteristics of a wide-band cavity backed annular patch antenna for multipolarization operations". IEEE Transactions on Antennas and Propagation. 53 (1): 466–474. doi:10.1109/tap.2004.838794.{{cite journal}}: CS1 maint: multiple names: authors list (link)
• Daniel Valderas; Pedro Crespo; Cong Ling (April 2010). "UWB portable printed monopole array design for MIMO communications". Microwave and Optical Technology Letters. 52 (4): 889–895. doi:10.1002/mop.25047. {{cite journal}}: Unknown parameter |last-author-amp= ignored (|name-list-style= suggested) (help)
• Sung Ho Chae; Se-keun Oh; Seong-Ook Park (2007). "Analysis of Mutual Coupling, Correlations, and TARC in WiBro MIMO Array Antenna". IEEE Antennas and Wireless Propagation Letters. 6: 122–125. doi:10.1109/lawp.2007.893109.
• Po-Chuan Hsieh; Fu-Chiarng Chen (July 2008). "The relation of TARC-based radiation efficiency and port termination for multiple antenna systems". Antennas and Propagation Society International Symposium: 1–4, 5–11. doi:10.1109/APS.2008.4619408=.
• Z. B. Zainal-Abidin; et al. (2011). "Design of 2 x 2 U-shape MIMO slot antennas with EBG material for mobile handset applications" (PDF). Progress In Electromagnetics Research Symposium Proceedings. pp. 1275–1278. hdl:10454/5467. ISBN 978-1-934142-16-5.
• A. R. Mallahzadeh; S. Es'haghi; A. Alipour (2009). "DESIGN OF AN E-SHAPED MIMO ANTENNA USING IWO ALGORITHM FOR WIRELESS APPLICATION AT 5.8 GHz" (PDF). Progress In Electromagnetics Research, PIER 90: 187, 203. {{cite journal}}: Unknown parameter |last-author-amp= ignored (|name-list-style= suggested) (help)