A low SLL series‐fed patch array antenna using simple and compact ridge waveguide‐based unequal feeding network

In this paper, the design of a low sidelobe level (SLL) 10 × 10‐element series‐fed patch antenna array is presented. A ridge waveguide‐based nonuniform feeding layer is employed to excite the array. Each column of the antenna array includes a tapered 10‐element series fed patch antenna array. By using a simple and compact center‐fed ridge waveguide, a low loss feeding layer is achieved. The coupling between the ridge waveguide and the standard WR‐75 flange is performed by employing a proposed stepped transition. The measured results indicate that the maximum gain is 24.1 dBi and the SLL is lower than −20 dB in both H‐ and E‐planes at 12.7 GHz. The proposed low SLL planar series‐fed patch antenna array can be utilized as an acceptable candidate for radar applications.