Review on Wideband and Compact CTS Arrays at Millimeter Waves

In this paper, three state-of-the-art parallel-fed continuous transverse stub (CTS) arrays are presented. They operate at various frequency bands ranging from 20 GHz up to 86 GHz. The multiple capabilities of this architecture, such as side-lobe level reduction, active beam switching, and wideband operation with an ultra-low-profile, are here reviewed. Moreover, the suitability of the antenna concept for multiple fabrication technologies is demonstrated. The performance and key design solutions of three prototypes manufactured using milling techniques, low-temperature co-fired ceramic and printed circuit board technology are showcased.