Design of miniaturised UWB log‐periodic end‐fire antenna using several fractals with WLAN band‐rejection

Abstract

Several microstrip log‐periodic antennas are introduced having square Koch, triangular Koch, tree and Giuseppe Peano fractals applied to the edges of their branches with substrate integrated waveguide feed system. The proposed antennas are designed for end‐fire radiation and ultra‐wideband (UWB) operation (3.1–10.6 GHz), which achieve a fidelity factor of better than 0.9 due to the low variation of their phase centres. These antennas are effectively miniaturised and are suitable for impulse radio‐UWB and medical imaging. To prevent interference with commercial bands of 5.8 and 8.3 GHz, two spiral slots are cut on the patch. Their frequency and time‐domain operations and also miniaturisation are compared with those in the available literature. A prototype model of an end‐fire log‐periodic microstrip antenna with the Giuseppe Peano fractal applied to the edges of truncated rhombic branches is fabricated and measured to evaluate and demonstrate its stated properties and specifications.

A Slotted Planar Antenna for 5G Applications

“…Where w is the patch width, 𝑓 -is the antenna resonant frequency, and 𝜀 -is the substrate of the dielectric constant. The effective dielectric constant may be calculated using the following formula [10] :…”

Design and Optimization of Compact Printed Log-Periodic Dipole Array Antennas with Extended Low-Frequency Response

“…Several fractal shapes can be used as suggested in [29]. Moreover, other fractal shapes such as Minkowski fractal [30], Quasi-Minkowski fractal [31], Koch fractal [32], Triangular Koch fractal [33], square lock fractal [33], tree-fractal [33], peano fractal [33], and meander line [33] are widely used to miniaturize the size of the antenna. A detailed comparison of PLPDAs with different fractal shapes and different iterations is shown in [33] for UWB applications.…”

“…Moreover, other fractal shapes such as Minkowski fractal [30], Quasi-Minkowski fractal [31], Koch fractal [32], Triangular Koch fractal [33], square lock fractal [33], tree-fractal [33], peano fractal [33], and meander line [33] are widely used to miniaturize the size of the antenna. A detailed comparison of PLPDAs with different fractal shapes and different iterations is shown in [33] for UWB applications. Additionally, a novel design of PLPDA with Peano fractals at the edge of truncated rhombic branches with spiral slots is also proposed in this reference, that can operate in the UWB band of 3.1-10.6 GHz with a band rejection in the 5.8 GHz and 8.3 GHz band.…”

Three Configurations of Compact Planar Multistub Microstrip Antennas for mmW Mobile Applications

“…For antenna 2, the design rules of the log periodic antenna are used with the same feeding network. For the log-periodic antenna, the lengths (L) and widths (w) of adjacent elements are calculated by using the following [15,16]:…”