A miniaturized three‐dimensional log periodic Koch‐dipole array antenna using T‐shaped top loading

Abstract

A log periodic dipole array antenna (LPDA) is miniaturized by using top loading. The Koch dipole further helps to shrink the antenna size. Different from the traditional LPDA that features a planar structure, the proposed log periodic Koch-dipole array (LPKDA) adopts two identical pairs of top-loaded Kochdipoles that deploy orthogonally along the feed line. This results in a tree-like three-dimensional antenna geometry, which introduces one extra dimension of freedom for antenna designers. The influence of the top-loading on antenna's impedance bandwidth is studied under the Wheeler and Chu's limit. The characteristic of the Koch-dipole is analyzed. Taking the advantage of 3D printing technology to fabricate complex models, the proposed LPKDA is printed by selective laser melting using aluminum alloy. The simulated −10-dB bandwidth is 117.4% (0.91-3.54 GHz) The LPKDA has the average gain of 5.3 dBi over the 1 to 3.5 GHz impedance bandwidth in measurement. Radiation patterns agree well in simulation and measurement. Compared with conventional LPDA of the same impedance bandwidth, the proposed LPKDA features 42%-dimensional reduction. This letter proves the feasibility of antenna optimization by using both innovative design method and advanced fabrication process.

Additively Manufactured Antennas and Electromagnetic Devices

“…In the same process, sub-miniature push-on micro (SMPM) male connectors were printed, resulting in a final antenna ready for testing. In [50], SLM was employed to produce a log-periodic Koch dipole array from an aluminum alloy, designed to accommodate an SMA connector as a feeder. This antenna array was intended to operate between 1 GHz and 3.5 GHz, and the measurements closely matched those of the simulation results.…”