Transient field of non-reflecting resistively loaded dipole excited by ultrawide band signals

• Main Authors: Choudhury, A.K., Sammadar, S.N., Mokole, E.
• Format: Conference Proceeding
• Language: English
• Subjects: Broadband antennas; Dipole antennas; Frequency domain analysis; Impedance; Loaded antennas; Polarization; Pulse generation; Radar antennas; Radar scattering; Transmitting antennas
• DOI: 10.1109/APS.1998.701779

The nature of the transmitted field (far field) of broadband (resistively loaded non-reflecting dipole) antennas excited by short pulses are investigated. First the transient field due to coplanar orthogonal resistively loaded non-reflecting dipole (Wu-King model) excited by a single and multiple cycles of short pulses (sinusoid) are obtained in the frequency domain. The time domain expression for the transient field is obtained by taking the inverse Fourier transform of the frequency domain expression for the transient field. Unlike the case of ordinary (nonresistive) dipoles, the field due to the resistively loaded non-reflecting dipole excited by a single cycle sinusoid is extended to 1.5 cycles instead of 1.75 cycles. Polarization characteristics are somewhat different from that of the coplanar orthogonal dipoles excited by a single sinusoid (ultrawide band). In the case of a resistively loaded half-wave non-reflecting dipole excited by a single cycle sinusoid, circular polarization occurs in the broadside direction during the third and the fourth cycles. The linear polarization occurs during the first and the the last (sixth) cycles and elliptic polarization occurs and lasts during the second and the fifth cycles. In the case of resistively loaded half-wave non-reflecting dipole excited by a single cycle sinusoid, circular polarization occurs in the broadside direction during the third and the fourth cycles. The linear polarization occurs during the first and the last (sixth) cycles and elliptic polarization occurs and lasts during the second and the fifth cycle.