Wide Impedance-Bandwidth Microstrip Comb-Line Array Antenna Using High Sidelobe Suppression Parasitic Elements

In this letter, we introduce a wide impedance bandwidth microstrip comb-line array antenna in the millimeter-wave band. To achieve wide impedance bandwidth performance, a series-fed array antenna consisting of three types of radiating structures is designed on a substrate utilizing printed circuit board technology. Different from the traditional comb-line array, parasitic components are introduced in the vicinity of the radiating elements to obtain low sidelobe levels (SLLs). The antenna is constructed and measured to confirm its viability. The measured impedance bandwidth (voltage standing-wave ratio (VSWR)
$\leq$
2) is 30.02% (20.1 GHz to 27.2 GHz) with satisfactory impedance matching. Meanwhile, the SLL of the comb antenna is about −22 dB at 26.6 GHz. Therefore, the proposed antenna boasts advantages including a simple manufacturing process with low fabrication cost, ease of integration, wide impedance bandwidth, and low sidelobes.