Enhanced Pencil-Beam Scanning CTS Leaky-Wave Antenna Based on Meander Delay Line

Abstract

This letter presents a millimeter-wave (mmW) continuous transverse stub (CTS) leaky-wave antenna (LWA) with pencil-beam broadside radiation, high scanning-rate, and low sidelobe levels (SLLs) characteristics. A parallel-plate waveguide (PPW) meander delay line is employed to control the phase constant of the proposed LWA. By adjusting the length of the transverse electromagnetic TEM-mode PPW delay line, the phase difference between adjacent radiating elements can be altered, achieving flexible control of scanning-rate. Match stubs close to the radiation slots are utilized to suppress the open stopband, which help enlarge the beam scanning range. A linear source generator excited by multiple ports with amplitude tapering is employed to generate the quasi-TEM wave. Combined with additional amplitude tapering among the CTS radiation slots, low SLLs at both principal planes are realized. Experimental results show that the LWA with 12 radiation elements has a scanning range of −68° to 42° over the frequency range of 26–34 GHz (a scanning-rate of 13.75°/GHz) with SLLs lower than 13.5 dB/16.6 dB and a peak gain of over 22.5 dBi.