The dielectric rod antenna is of tremendous importance in applications requiring a
nonmetallic antenna or a radiating element, with its largest extent in longitudinal direction,
rather than a relatively large aperture in the plane transverse to the desired direction of
maximum radiation. Since the rod seals the aperture of its excitation system, it can be
used in applications where the excitation system has to be sealed. The dielectric rod
antenna is mechanically strong and robust. However, rain and moisture on the surface of
the rod show an effect on the antenna gain. Dielectric rod antennas are used in adaptive
phased arrays in Space Division Multiple Access (SDMA) applications. Many researchers
have reported in the literature on Polystyrene, Perspex and Teflon dielectric rod antennas
(Chatterjee and Chatterjee, 1956 and 1957; Rama Rao et al., 1957; Rama Rao, 1959; and
Ramanujam and Chatterjee, 1962a and 1962b).
This paper proposes to determine the length and taper angle of tapered Nylon rod
antenna of circular cross section, for which the optimum radiation characteristics, i.e.,
maximum directivity and minimum Side Lobe Level (SLL), may be obtained by computing
the radiation pattern, using expressions for far field quantities, as given by Anand and
Rajeswari (1968). |
to 
. For each of these lengths, the radiation patterns
Nylon rod antennas with different taper angles are computed. The variation
Half Power Beam Width (HPBW) from Side Lobe Level (SLL), with length and
angle, shows a 2.5 taper over a length of 
