The Effects of Measurement Distance on the Broadside Symmetric Leaky Wave Antenna

The effects of measuring a symmetric broadside leaky wave antenna (LWA) at finite distances are examined. In particular, the broadside beam behavior near the beam splitting condition is studied since the directivity error can be significant. The patterns at various distances, including the rule of thumb distance of 2L² / lambda_o, are calculated and compared to the far-field (FF) pattern. In addition, variations in measurement error at the finite distances due to the sign of the leaky wave phase constant are identified.