Millimeter-Wave Miniaturized Substrate Integrated Multibeam Antenna

Substrate integrated waveguide (SIW) presents an excellent candidate in the development of millimeter-wave integrated printed multibeam antenna depending on its inherent advantages. But the SIW-based multibeam antenna usually occupies a large circuit size. To overcome this weakness, we propose a novel miniaturized SIW multibeam antenna at the center frequency 33.5 GHz. Such a structure can be considered as an asymmetric multimode beamforming network (BFN) directly integrated with a compact antipodal linearly tapered slot antenna (ALTSA) array without additional phase shifters or connection lines. It has smaller circuit size compared with the state-of-the-art SIW multibeam antenna technology. Four beams with different beam directions can be generated to cover the angle range of around 76° with 3 dB beam-widths at the center frequency.