Dual-Polarized Shared-Aperture Frequency-Scanning CTS Antenna with Wide Angle

A dual-polarized (DP) shared-aperture frequency-scanning continuous transverse stub (CTS) antenna with wide scanning range is presented in this paper. In order to mitigate the open stopband and realize continuous beam-scanning including broadside, a novel “L”-type CTS radiation element is proposed. An equivalent circuit model is established to analyze the input impedance and reflection coefficient of the proposed CTS element by using the transmission line theory. The antenna array consists of an orthogonally arranged shared-aperture DP-CTS radiation array and the corresponding linear source generators (LSGs). The amplitude tapering of Taylor distribution is applied to suppress the sidelobe level (SLL). A metallic LSG is designed to reduce the transmission loss with a tapered feeding probe being adopted to broaden the bandwidth. A 12-element prototype is simulated and fabricated. A reasonable agreement between simulation and measurement is achieved. Experimental results show that the DP antenna has an impedance bandwidth of 8 ∼ 14 GHz and a port isolation higher than 21 dB. The scanning ranges for both polarizations are from −73° to 20° with a maximum gain of 23.9 dBi and a SLL lower than −16.6 dB. The proposed DP-CTS frequency-scanning antenna could be applied in radar detection systems.