  The low-frequency radio telescope of the Square Kilometre Array (SKA) is
being built by the international radio astronomical community to (i) have
orders of magnitude higher sensitivity and (ii) be able to map the sky several
hundred times faster, than any other existing facilities over the frequency
range of 50 - 350 MHz. The sensitivity of a radio telescope array is in
general, dependent upon the number of electromagnetic sensors used to receive
the sky signal. The total number of them is further constrained by the effects
of mutual coupling between the sensor elements, allowable grating lobes in
their radiation patterns, etc. The operating frequency band is governed by the
desired spatial and spectral responses, acceptable sidelobe and backlobe
levels, radiation efficiency, polarization purity and calibratability of
sensors' response. This paper presents a brief review of several broadband
antennas considered as potential candidates by various engineering groups
across the globe, for the low-frequency radio telescope of SKA covering the
frequency range of 50 - 350 MHz, on the basis of their suitability for
conducting primary scientific objectives.
