This paper presents the antenna design parameter dependency on the impedance and radiation characteristics of a terahertz coplanar stripline dipole antenna. The antenna response is numerically investigated by applying a semi-infinite substrate and by generating a constant voltage source to drive a signal on the antenna. In this way, we can analyze the antenna characteristics without the photoconductive material response and the substrate lens geometrical effects. Further, we explain the mechanism underlying the preferable uses of several millimeter length DC bias striplines in a typical THz coplanar stripline dipole antenna design. The antenna, consisting of a center dipole connected to long bias striplines, has a traveling wave characteristic supporting an attenuated current, rather than a resonant characteristic supporting a standing wave of current. The traveling wave behavior produces stable antenna input impedances and minimal changes in the antenna radiation patterns. We also found that the length of the center dipole has a prominent effect on the antenna gain response.
2. Lee, C. H., "Picosecond optoelectronic switching in GaAs," Appl. Phys. Lett., Vol. 30, 84-86, 1977.
doi:10.1063/1.89297
3. Auston, D. H., "Picosecond optoelectronic switching and gating in silicon," Appl. Phys. Lett., Vol. 26, 101-103, 1975.
doi:10.1063/1.88079
4. Auston, D. H., K. P. Cheung, and P. R. Smith, "Picosecond photoconducting Hertzian dipoles," Appl. Phys. Lett., Vol. 45, No. 3, 284-286, 1984.
doi:10.1063/1.95174
5. Grischkowsky, D., I. N. Duling, III, J. C. Chen, and C.-C. Chi, "Electromagnetic shock waves from transmission lines," Phys. Rev. Lett., Vol. 59, No. 15, 1663-1666, 1987.
doi:10.1103/PhysRevLett.59.1663
6. Yang, T., S. Song, H. Dong, and R. Ba, "Waveguide structures for generation of terahertz radiation by electro-optical process in GaAs and ZnGeP2 using 1.55 μm fiber laser pulses," Progress In Electromagnetics Research Letters, Vol. 2, 95-102, 2008.
doi:10.2528/PIERL07122806
7. Andres-Garcia, B., L. E. Garcia-Munoz, D. Segovia-Vargas, I. Camara-Mayorga, and R. Gusten, "Ultrawideband antenna excited by a photomixer for terahertz band," Progress In Electromagnetics Research, Vol. 114, 1-15, 2011.
8. Zyaei, M., A. Rostami, H. Haji Khanmohamadi, and H. Rasooli Saghai, "Room temperature terahertz photodetection in atomic and quantum well realized structures," Progress In Electromagnetics Research B, Vol. 28, 163-182, 2011.
9. O'Shea, P. G. and H. P. Freund, "Free-electron lasers: Status and applications," Science, Vol. 292, 1853-1858, 2001.
doi:10.1126/science.1055718
10. Mineo, M. and C. Paoloni, "Comparison of THz backward wave oscillators based on corrugated waveguides," Progress In Electromagnetics Research Letters, Vol. 30, 163-171, 2012.
doi:10.2528/PIERL12013107
11. Wei, S., J. Weili, and J. Wanli, "Investigation of ultra-wideband electromagnetic radiation based on Si-GaAs photoconductive switches," Microw. Opt. Tech. Lett., Vol. 54, No. 4, 900-904, 2012.
doi:10.1002/mop.26683
12. Maraghechi, P. and A. Y. Elezzabi, "Experimental confirmation of design techniques for effective bow-tie antenna lengths at THz frequencies," J. Infrared Milli. Terahz. Waves, Vol. 32, 897-901, 2011.
doi:10.1007/s10762-011-9805-6
13. Brown, E. R., A. W. M. Lee, B. S. Navi, and J. E. Bjarnason, "Characterization of a planar self-complementary square-spiral antenna in the THz region," Microw. Opt. Tech. Lett., Vol. 48, No. 3, 524-529, 2006.
doi:10.1002/mop.21398
4. Tani, M., S. Matsuura, K. Sakai, and S. Nakashima, "Emission characteristics of photoconductive antennas based on low-temperature-grown GaAs and semi-insulating GaAs," Appl. Opt., Vol. 36, No. 30, 7853-7859, 1997.
doi:10.1364/AO.36.007853
15. Miyamaru, F., Y. Saito, K. Yamamoto, T. Furuya, S. Nishizawa, and M. Tani, "Dependence of emission of terahertz radiation on geometrical parameters of dipole photoconductive antennas," Appl. Phys. Lett., Vol. 96, No. 21, 211104, 2010.
doi:10.1063/1.3436724
16. Diao, J., F. Yang, L. Du, J. Ouyang, and P. Yang, "Enhancing terahertz radiation from dipole photoconductive antenna by blending tips," Progress In Electromagnetics Research Letters, Vol. 25, 127-134, 2011.
17. Maraghechi, P. and A. Y. Elezzabi, "Enhanced THz radiation emission from plasmonic complementary Sierpinski fractal emitters," Opt. Express, Vol. 18, No. 26, 27336-27345, 2010.
doi:10.1364/OE.18.027336
18. Diao, J. M. , F. Yang, Z. P. Nie, J. Ouyang, and P. Yang, "Separated fractal antennas for improved emission performance of terahertz radiations," Journal of Electromagnetic Waves and Applications, Vol. 26, No. 8-9, 1158-1167, 2012.
doi:10.1080/09205071.2012.710562
19. Dragomana, D. and M. Dragomanb, "Terahertz fields and applications," Progress in Quan. Electron., Vol. 26, No. 1, 1-66, 2004.
doi:10.1016/S0079-6727(03)00058-2
20. Van Exter, M. and D. Grischkowsky, "Characterization of an optoelectronic terahertz beam system," IEEE Trans. Microwave Theory Tech., Vol. 38, No. 11, 1684-1691, 1990.
doi:10.1109/22.60016
21. Harde, H. and D. Grischkowsky, "Coherent transients excited by subpicosecond pulses of terahertz radiation," J. Opt. Soc. Am. B, Vol. 8, 1642-1651, 1991.
doi:10.1364/JOSAB.8.001642
22. BATOP GmbH, , http:/www.batop.de/.
23. Shafai, L. and S. Noghanian, Modern Antenna Handbook, C. A. Balanis (ed.), Chapter 9, Wiley, 2008.
24. Chen, H.-T., J.-X. Luo, and D.-K. Zhang, "An analytic formula of the current distribution for the VLF horizontal wire antenna above lossy half-space," Progress In Electromagnetics Research Letters, Vol. 1, 149-158, 2008.
doi:10.2528/PIERL07112904
25. Kominami, M., D. M. Pozar, and D. H. Schaubert, "Dipole and slot elements and arrays on semi-infinite substrate," IEEE Trans. Antennas Propagat., Vol. 33, No. 6, 600-607, 1985.
doi:10.1109/TAP.1985.1143638
26. Nguyen, T. K., T. A. Ho, H. Han, and I. Park, "Numerical study of self-complementary antenna characteristics on substrate lenses at terahertz frequency," J. Infrared Milli. Terahz. Waves, Vol. 33, No. 11, 1123-1137, 2012.
doi:10.1007/s10762-012-9929-3
27. Nguyen, T. K. and I. Park, "Resonant antennas on semi-infinite and lens substrates at terahertz frequency," Convergence of Terahertz Sciences in Biomedical Systems, 181-193, G.-S. Park, Ed., Springer, 2012.
28. Van Rudd, J. and D. M. Mittleman, "D. M. Mittleman design in terahertz time-domain spectroscopy," J. Opt. Soc. Am. B, Vol. 19, No. 2, 319-329, 2002.
doi:10.1364/JOSAB.19.000319
29. Rutledge, D. B. and M. S. Muha, "Imaging antenna arrays," IEEE Trans. Antennas Propagat., Vol. 30, No. 4, 535-542, 1982.
doi:10.1109/TAP.1982.1142856
30. Tonn, D., "Radiation patterns of standing wave and traveling wave microstrip dipoles,", Master's Thesis, University of Connecticut, 1994.
31. Coleman, C., An Introduction to Radio Frequency Engineering, 258-259, Cambridge University Press, Cambridge, New York, 2004.
doi:10.1017/CBO9780511801327
Submit
