Abstract
Non-Foster elements are introduced to augment an Egyptian axe dipole (EAD) antenna-based system in order to expand its directivity bandwidth. The frequency-agile properties of the original antenna system are investigated near 300 MHz by linearly and discretely changing the values of its internal reactive element. The curve-fit reactance versus frequency curve is established. It is reproduced approximately by augmenting the antenna system with two non-Foster elements implemented internally in one of its near-field parasitic elements and with negative impedance convertor (NIC) designs. It is demonstrated that the resulting electrically small antenna system is capable of achieving excellent unidirectional radiation performance, including a broadside directivity in the range from 5.78 to 6.24 dB with more than a 20 dB front-to-back ratio (FTBR) over a 13% instantaneous fractional bandwidth. The corresponding half-power beamwidths in the E-and H-planes, respectively, are 78° and 138° the radiation efficiency exceeds 65%.
Original language | English (US) |
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Article number | 6484100 |
Pages (from-to) | 421-424 |
Number of pages | 4 |
Journal | IEEE Antennas and Wireless Propagation Letters |
Volume | 12 |
DOIs | |
State | Published - 2013 |
Keywords
- Directivity
- electrically small antennas (ESAs)
- front-to-back ratio (FTBR)
- negative impedance converter (NIC)
- non-Foster element
- parasitic element
ASJC Scopus subject areas
- Electrical and Electronic Engineering