High Gain Backward Scanning Substrate Integrated Waveguide Leaky Wave Antenna

A novel substrate integrated waveguide (SIW)-based leaky-wave antenna (LWA) is presented for backward endfire radiation and wide range backward scanning from backward endfire to near broadside. Wide backward range, high gain, lower sidelobe levels are achieved by properly designing the radiating slots and unit cell. The presented design provides the measured backward endfire (-90°) gain of 9.5 dBi at 16.7 GHz and the measured gain of 17.4 dBi at 19.8 GHz. Gain increases with frequency as the beam begins to move away from backward endfire to near broadside providing 80° of wide backward scanning range. Sidelobe levels and return loss are well below -10 dB. A prototype of the proposed design is fabricated. The measured results are in good agreement with simulated ones.