Title :
Ultrawideband Circularly Polarized Spiral Antenna Using Integrated Balun With Application to Time-Domain Target Detection
Author :
Mao, Shau-Gang ; Yeh, Jen-Chun ; Chen, Shiou-Li
Author_Institution :
Grad. Inst. of Comput. & Commun. Eng., Nat. Taipei Univ. of Technol., Taipei, Taiwan
fDate :
7/1/2009 12:00:00 AM
Abstract :
The design of a wideband circularly polarized (CP) equiangular spiral antenna is described. Contrary to the conventional spiral antenna using the coaxial line or the vertically connected feeding structure, a tapered microstrip balun is fully integrated into one spiral arm of the proposed antenna and hence this construction can be realized completely planar. The measured results show that the return loss is better than 10 dB from 3.75 to 18.6 GHz, the axial ratio is below 3 dB from 3 to 14.5 GHz, the radiation is bidirectional with opposite polarization, and the antenna peak gain is 3.5 to 7 dBic. The time-domain characteristic of the transmitting/receiving system using the proposed ultrawideband (UWB) CP antennas is investigated by transient response. The pulse distortion is insignificant and is verified by the measured antenna performance with high signal fidelity (ges 0.89) and low variation of group delay (les 0.1 ns ). The transmitting/receiving antenna system using the proposed antennas is constructed to demonstrate the CP characterization and to detect the target position.
Keywords :
baluns; coaxial cables; polarisation; receiving antennas; spiral antennas; transient response; transmitting antennas; ultra wideband antennas; circularly polarized antenna; coaxial line; equiangular spiral antenna; integrated balun; pulse distortion; tapered microstrip balun; target position detection; time-domain target detection; transient response; transmitting/receiving antenna; ultrawideband antenna; vertically connected feeding structure; Impedance matching; Microstrip antennas; Object detection; Polarization; Receiving antennas; Spirals; Time domain analysis; Transmitting antennas; Ultra wideband antennas; Ultra wideband technology; Circular polarization; spiral antenna; transmitting/receiving antenna system; ultrawideband (UWB);
Journal_Title :
Antennas and Propagation, IEEE Transactions on
DOI :
10.1109/TAP.2009.2021883