New broad angle frequency scanning antenna with narrow bandwidth based on a CRLH structure

摘要

A new type of frequency scanning slot array antenna using composite right/left-handed (CRLH) waveguide as a feeding structure is presented in this study. The waveguide is loaded periodically with short-circuited air-filled double-ridge stubs, which permit the CRLH propagation. The feeding structure is highly dispersive in order to scan a wide angular sector with a narrow frequency sweep. It also easily allows amplitude tapering of the array elements. An eight-element longitudinal slot array designed for X-band operation with -22 dB sidelobe level has been built and tested. Good agreement between simulations and measurements was obtained. The structure exhibits 31° of scanning over a frequency bandwidth of only 6%, and low return loss in its band of operation.