A Ka-Band Leaky-Wave Antenna Array With Stable Gains Based on HMSIW Structure

In this letter, a Ka-band leaky-wave antenna array based on half-mode substrate integrated waveguide (HMSIW) structure is proposed, which is capable of scanning beam from backward to forward including broadside with stable gains. This array is fed by a SIW-to-HMSIW power-divider and consists of two back-to-back HMSIWs with one row of sinusoidally modulated vias, which can excite the first-space harmonic radiation. Periodic slots are designed at the edge of top-wall to suppress the open stopband and etched on the ground to enhance the scanning rate using the slow-wave effect. The measured results validate that when the operating frequency changes from 27 GHz to 40 GHz, the proposed array has the beam scanning from –40° to 30° with the peak gain varies from 13.4 to 15 dBi.