T-type folded SIW-based leaky-wave antennas with wide scanning angle and low cross-polarization

In this paper, a leaky-wave antenna (LWA) with wide scanning angle and low cross-polarization is proposed based on a T-type folded substrate-integrated waveguide (FSIW). Transverse slots with a sinusoidal distribution pattern are etched on the surface of the FSIW so that transmission lines with slow-wave characteristics can excite and radiate -1 order harmonics. The length of the transverse slot affects the dispersion characteristics of the transmission line, and the sinusoidal modulation period controls the operating range of the LWA. In the frequency range of 8.3-15 GHz, the proposed LWA achieves a wide scanning ranging from backward -42 degrees to forward +68 degrees continuously. The cross-polarization of the beam is also kept at less than -30 dB during this scanning. A prototype is fabricated and measured to confirm the design, and the measured results show an agreement with the simulated one.