C‐band frequency‐scanning continuous transverse stub array with high gain and low sidelobe level

A C-band substrate integrated waveguide based frequency-scanning continuous transverse stub (CTS) array with high gain and low sidelobe level (SLL) is presented in this paper. The newly suggested linear source generator (LSG) consists of a feeding probe, a main reflector, a sub-reflector, and two metal matching vias. By introducing one matching via on the left side of probe and another one on the right side of the sub-reflector, a broadband LSG is obtained to excite the CTS array with a wide scanning range. The operating mechanism of the two matching vias is analysed. In order to reduce SLL, a serial-fed array with asymmetrically distributed stub width is designed according to Chebyshev distribution for the first time. A prototype of 12-element array is designed, simulated and measured, and excellent agreements are achieved. The measured beam-scanning range is from -52 degrees to 2 degrees within the operating frequency of 5.6-8 GHz, in which |S-11| is less than -10 dB. The maximum gain is 22 dBi and the SLL varies between -21 dB and -18.2 dB. The proposed design approach can be applied to other bands and other level distributions. The proposed frequency scanning array has great potentials in radar and detection systems.