Wideband Low‐Sidelobe CTS Antenna Array with Asymmetrical Feed Topology and Small Power Division Ratio Power Dividers

ABSTRACT This letter presents a wideband low‐sidelobe Continuous Transverse Stub (CTS) array antenna operating across the 26–42 GHz frequency range. To address the issue of frequency‐dependent instability in the first sidelobe, which commonly arises in designs employing large power division ratio dividers, a novel asymmetrical feed topology is introduced, utilising dividers with small power division ratios. The design is validated through a 40‐element array based on a –25 dB Taylor synthesis. Independent E‐ and H‐plane feeding networks are employed to shape the radiation pattern envelopes, implemented using parallel plate waveguide (PPW) and single‐ridge waveguide (SRGW) structures, respectively. Simulation and measurement results exhibit good agreement, achieving a measured fractional bandwidth of 47% and sidelobe ripple within ‐25±2 dB.