In this paper, antenna ultra wideband enhancement by non-uniform matching is proposed. The antenna consisted of a rectangular shaped radiator with two convex circled corners. Simulated results using CST Microwave Studio and measured results of a fabricated antenna concord well to prove that it can operate from about 3.5 GHz to 4.6 GHz and from 7.4 GHz to 12.7 GHz for S11 (dB) < -10 dB. In addition, a good impedance matching is noted in the IEEE radar engineering X band range since the return loss coefficient remains below -50 dB value at 9.5 GHz and can reach -45 dB at 11 GHz. A current density comparison at 11 GHz, supporting our argument, between a stepper corner and convex corner demonstrates that the current density can reach 52 A/m with a convex corner whereas it does not exceed 33 A/m for the antenna with a stepper corners. Radiation patterns at various frequencies and peak gains show clearly interesting features of such antennas.
2. Sun, D. and L. You, "A broadband impedance matching method for proximity coupled microstrip antenna," IEEE Transaction on Antennas and Propagation, 1392-1397, Apr. 2010.
3. Kelly, J. R., P. S. Hall, and P. Gardner, "Planar band-notched UWB antenna," 3rd Conference Eucap'2009, 1636-1639, Mar. 2009.
4. Wong, K. L., Compact and Broadband Microstrip Antennas, Wiley, NY, 2002.
5. Sim, C.-Y.-D., W.-T. Chung, and C.-H. Lee, "Compact slot antenna for UWB applications," Antenna and Wireless Propagation Letters, 62-66, 2010.
6. Dastranj, A. and H. Abiri, "Bandwidth enhancement of printed E-shaped slot antennas fed by CPW and microstrip line," IEEE Transaction on Antennas and Propagation, 1402-1407, Apr. 2010.
7. Lin, C.-C. and H.-R. Chuang, "A 3-12 GHz UWB planar triangular monopole antenna with ridged ground-plane," Progress In Electromagnetics Research, Vol. 33, 307-321, 2008.
8. Choi, S. H., J. K. Park, S. K. Kim, and J. Y. Park, "A new ultra-wide band antenna for UWB application," Microwave and Optical Technologies Letters, 399-401, Mar. 2004.
9. Duroc, Y., T.-P. Vuong, and S. Tedjini, "A time/frequency model of ultrawideband antennas," IEEE Transaction on Antennas and Propagation, 2342-2350, Aug. 2007.
10. Chen, D. and C. H. Cheng, "A novel compact ultra-wideband (UWB) wide slot antenna with holes," Progress In Electromagnetics Research, Vol. 94, 343-349, 2009.
11. Fallahi, R., A. A. Kalteh, and M. G. Roozbahani, "A novel UWB elliptical slot antenna with band-notched characteristics," Progress In Electromagnetics Research, Vol. 82, 127-136, 2008.
12. Zhang, G.-M., J.-S. Hong, and B.-Z. Wang, "Two novel band-notched UWB slot antennas fed by microstrip line," Progress In Electromagnetics Research, Vol. 78, 209-218, 2008.
13. Sze, J. Y. and K. L. Wong, "Bandwidth enhancement of a microstripline-fed printed wide-slot antenna," IEEE Transaction on Antennas and Propagation, 1020-1024, Jul. 2011.