Design of a closely‐spaced, multiple‐element parasitic antenna array

Abstract

A new design of a closely-spaced, multiple-element parasitic antenna array is proposed based on the identified dominant surface wave mechanism. The optimum surface wave phase velocity, which leads to the maximum antenna gain, is determined for a fixed length array. The antenna input impedance is presented and optimized using folding technique. Both numerical simulations and measurements are implemented.

Backward Surface Wave Propagation and Radiation along a One-Dimensional Folded Cylindrical Helix Array

“…More recently, it has been successfully applied to both wave propagation and antenna radiation problems [12]. The extraction process has been explained in detail in [4] and will not be repeated here. Consider the following:…”

“…The total length of the array is assumed to be 0.5 0 . Given this fixed array size, the propagation constant of the surface wave has to be carefully determined to maximize the directivity of the array, which is similar to the 1D metal wire antenna array design [4]. The optimum phase constant opt for this halfwavelength array is found to be −1.98 0 .…”

“…It was found in [3] that the transmission loss of EM energy along a 1D metal rod array is smaller than 1.5 dB/ 0 , which can be attributed to the strong coupling between closely spaced rods (0.054 0 ). For the second application, a closely spaced, multiple-element parasitic antenna array was designed and implemented, with its interelement spacing being as small as 0.02 0 [4].…”