Tri‐polarised antenna – a virtual rotatable dual‐polarised antenna used in polarised beampattern synthesis

Abstract

Tri‐polarised antennas are exploited to synthesise the optimal polarised beampattern in this study. First, the characteristics of a single tri‐polarised antenna are studied with an infinite current sheet model. Using the cross‐product algorithm, the authors find that three co‐located orthogonal current sheets are equivalent to a pair of orthogonal current sheets in a particular orientation. It implies that the tri‐polarised antenna is just virtually equivalent to a rotatable dual‐polarised antenna. Then by formulating the problem in a convex form, they adopt the convex optimisation algorithm to synthesise optimal polarised beampattern of the tri‐polarised array. The simulation results show that due to the increased orientation degree of freedom, the sidelobe and cross‐polarisation level of tri‐polarised array are significantly lower than the dual‐polarised array.

Polarised beampattern synthesis against array manifold mismatch

“…In many of these applications, it is required that the radiated beampattern has a certain polarisation and spatial power pattern with desired sidelobe level (SLL), null positions, and mainlobe beam width [4][5][6][7][8][9][10][11][12][13]. The joint synthesis of polarisation and power pattern has received much attention over recent years.…”

“…In [7, 8], the author compares the tri‐polarised antenna with a dual‐polarised antenna in polarised beampattern synthesis, and shows that the sidelobe and cross‐polarisation level of tri‐polarised array can be significantly reduced in contrast with the dual‐polarised array, especially in wide scanning angle. Concerning synthesis problem of fixed user‐defined desired polarisation and shaped power pattern, [9, 10] define the realisable co‐polarisation and cross‐polarisation directions and exploit the semi‐definite relaxation or convex optimisation schemes to control co‐polarisation, cross‐polarisation and total power in respective regions.…”