2-D Beam Steering Performance of a Triple Mode Horn Antenna Integrated With Risley Prism and Phase Correcting Surface

This paper presents a passive 2-D beam steering solution comprising of a triple-mode circular waveguide horn antenna operating at Ka-band frequency of 30 GHz, a pair of identical dielectric lenses employing Risley prism and a parabolic phase correcting surface. The circular waveguide horn antenna generates
${\mathrm {TE}}_{11}, {\mathrm {TM}}_{01}$
and
${\mathrm {TE}}_{21}$
modes independently. The pair of identical dielectric lenses employing the Risley prism concept are axially rotated individually and/or simultaneously to steer the radiated beam. The parabolic phase correcting structure is used to further improve the performance of the steered patterns. Overall, this antenna structure steers
${\mathrm {TE}}_{11}, {\mathrm {TM}}_{01}$
and
${\mathrm {TE}}_{21}$
modes patterns which makes it an attracting solution for tracking and communication applications. The proposed antenna system has been prototyped and experimentally verified in a compact antenna test range (CATR) chamber. The measured conical scan angles for
${\mathrm {TE}}_{11}$
mode is found to be around
$\pm 40{^\circ }$
with gain deviation less than 3 dB. The
${\mathrm {TM}}_{01}$
and
${\mathrm {TE}}_{21}$
modes are steered with a scan angle covering
$\pm 30{^\circ }$
.