A highly compact and highly efficient Huygens 1 × 4 antenna array is reported in this paper. The Huygens array consists of two major parts: a TE0.5, 0 mode SIW waveguide with seamlessly integrated phase inverters and two folded L-shaped metallic plates being orthogonally connected to it. Four magnetic dipoles are formed on the radiating aperture of the waveguide while four electric dipoles are realized on the plates. Their moments are orthogonal to each other and naturally in phase. Thus, Huygens cardioid radiation patterns are realized. The system operates around 10 GHz. It has a 7.7% simulated overlapped -10-dB impedance and 3-dB realized gain bandwidth from 9.44 to 10.2 GHz, 760 MHz. The peak realized gain value is 10.23 dBi within this bandwidth. The realized gain pattern at 10 GHz has a narrow (25°) half-power beamwidth (HPBW) in the H-plane (0°) and a wide (152°) HPBW in the E-plane (90°). The aperture efficiency of the array reaches 97.5%.