No abstract

To minimise the profile of Satcom-on-the-Move ground terminals, in this study, a twodimensional beam-scanning continuous transverse stub antenna that is based on a compact linear source generator (LSG) is presented. A periodic anti-symmetric two-step (ASTS) structure cascaded with a broadband network is used to construct a single-layer compact LSG. The concept of a parallel-plate waveguide polarisation twister is used to design the ASTS unit that acts as a TE 10 -to-transverse electromagnetic wave converter, to which chamfers and T-type grooves are added to improve the output plane wave performance over the entire frequency band. A prototype array operating in the band 10.95-12.75 GHz is designed, fabricated, and measured, and the experimental results agree well with the simulated ones. A beam-scanning range of �61°in elevation is achieved at the central frequency. Although only 29 of 36 slots (ϕ = 0°) contribute to the radiation, the antenna aperture efficiency is still over 60% due to the superior performance of the single-layer minimised LSG.This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Due to the huge potential of application in the communications, electronic jamming, and radar fields, circularly polarized (CP) array antennas with wide axial ratio (AR) scanning performance at wide frequency bandwidth have received great attention. A wideband scanning CP planar array antenna built by new, tightly coupled dipole array (CP-TCDA) elements, which have achieved promising results in terms of both scanning AR bandwidth and angle range in all scanning planes, is presented in this paper. Based on the shorted transmission line model, a CP-TCDA element arranged along the ±45° direction is constructed, which can shift the middle-frequency scanning blind zone out of band and thus obtain a wideband scanning AR bandwidth. Furthermore, the proposed CP-TCDA element adopts four shorting pins and four square parasitic strips, which improve wide-angle CP performance for xz-plane and diagonal-plane scans, respectively. An 8×8 left-handed CP planar array antenna based on the proposed CP-TCDA elements is designed and prototyped. The results show that the array antenna is able to operate over a 3:1 (4-12 GHz) overlapping bandwidth, and it meets the requirements of AR < 3 dB and active VSWR < 2.9 within a ±45° scanning angle range.INDEX TERMS array antenna, circularly polarized, phased antenna, scanning antennas