Compact Slow-Wave Half-Mode SIW Periodic Leaky-Wave Antenna With Continuous Beam Scanning and High Gain

A compact periodic leaky-wave antenna (PLWA) with continuous beam scanning characteristics and high gain is proposed based on a slow-wave half-mode substrate integrated waveguide (SW-HMSIW). The SW-HMSIW is designed on the basis of normal HMSIW by loading SW structures, consisting of metalized blind vias and patches, decelerating the phase velocity of an electromagnetic wave traveling in SIW, reducing the guided wavelength by 50%. Thus, the distance between the adjacent radiating slots in HMSIW PLWA is decreased by half, allowing twice as many radiating slots in SW-HMSIW PLWA with the same length. Then, the gain of such PLWA can be significantly increased. Besides, the loaded patches of SW structure under the radiating slots are extended to improve the impedance match of the radiating units, contributing to the open-stopband suppression. In consequence, the radiation beam can scan from backward to forward direction continuously. A prototype of the proposed SW-HMSIW PLWA is manufactured and measured. The total scanning angle of the proposed SW-HMSIW PLWA reaches 62.3° during the operating frequency range of (13.7 to 15.7) GHz with maximum gain of 11 dBi. The measured results agree well with the simulations.