Design of spherical meanderline antennas

We present a new study of an electrically small spherical antenna with Q approaching the lower bound. The structure is a natural successor to earlier work by some of the present authors [1] and is designed to excite the TM10 spherical mode for minimum Q. This new topology consists of meanderline arms entirely conformal to a spherical surface, facilitated by a precise conformal printing technique. Measurements of some antenna prototypes are presented in [2] but without a complete discussion of the electromagnetic design considerations. Here, we discuss details of the design parameters, material choices and a technique for mitigating the excitation of higher order modes which disrupt the impedance behavior of the structure. The presentation will include measured results of antennas at several different electrical sizes printed on both the concave and convex surface of a hemisphere.

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