Yao Zong

A wide‐angle frequency scanning narrow‐wall slotted waveguide array antenna with monopulse function is designed for two‐dimensional electrical scanning radar and communication systems. A novel slow wave waveguide formed by loading the periodic metal T‐shaped sheets onto the narrow wall is used to enhance the frequency scanning angular sector of the edge‐slotted waveguide traveling wave array. Two slotted waveguides with 35 radiation slots are arranged in a segmented frequency scanning structure to simultaneously achieve sum/difference patterns in the E‐plan. The prototype antenna fabricated and welded by aluminum is composed of 70 × 8 radiation slots with an overall size of 425 mm × 45 mm × 10 mm. The measured results show that the designed array exhibits a frequency scanning angle range of 20.6° at a relative operating bandwidth of 10% with greater than 50% aperture efficiency. The measured sidelobe level of sum beam is less than −17 dB, and null depth of difference beam pattern is below –25 dB over operating frequency band. This structure can be used to design the electrical two‐dimensional scanning array with a scanning sector greater than 20° × 80°.