Microwave Near-Field Focusing Beam Generation by Zeroth-Order Inward Cylindrical Traveling Leaky Wave

摘要

In this letter, a method is proposed to generate the near-field focusing beam inmicrowaves by using the TM-polarized zeroth-order inward cylindrical traveling leaky wave (ZICTLW), whose normal electric-field component is a truncated zero-thorder Hankel function of the first kind. The focusing property of ZICTLWis analyzed. Furthermore, the relation between the focusing property and the truncation region, which is used to remove the singularity, is investigated. In order to generate a focusing beam, a ZICTLW antenna is designed based on a three-layer radial wave-guide with both a capacitive sheet and a planar high-impedance sheet covered. The simulation and the measurement validate that the proposed antenna can generate a focusing zone, which can be controlled by the operating frequency.