基于非对称辐射单元的毫米波全金属漏波天线

Periodic leaky-wave antennas (PLWAs) have the potential for continuous beam scanning from backward quadrant to forward quadrant. There is specific application prospect for fully metallic PLWAs in millimeter-wave (MMW) radar systems. However, normal schemes are restricted by the open stopband (OSB) effect, leading to poor broadside scanning capability and limited beam coverage range. Currently, the quarter-wavelength transformer, the matching stub, nonidentical elements, shorting vias are the main methods of suppressing the OSB effect, but the solutions for fully metallic PLWAs haven′t been deeply discussed. Asymmetric radiating units are introduced in this paper to improve the OSB effect. An equivalent circuit model is presented to analyze and verify the effectiveness of this novel structure. Moreover, utilizing this method, an MMW fully metallic PLWA based on corrugated parallel-plate waveguide (PPW) is proposed. The continuous beam scanning capability from -47. 5° to 8. 5° is available in the frequency band of 26. 5-36 GHz with radiation efficiency above 78%. The result illustrates that the asymmetric radiating units could effectively suppress the OSB effect and be widely used in fully metallic PLWAs for wide-angle scanning.