Laboratory evaluation of open-loop resonator loading in a 2.4 Ghz multilayer printed LPDA
Year: 2026
Type: conference-paper
Abstract: This present study examines the effect of integrating open-loop resonators (OLRs) into a three-layer printed log-periodic dipole array (LPDA) operating in the 2400-2483.5 MHz ISM band. The initial LPDA geometry was derived from the Carrel design procedure using a scale factor of τ = 0.8 and a spacing factor of σ = 0.12, followed by full-wave optimization on three 1-mm FR-4 layers. A periodic 4 × 15 OLR array was then introduced on the middle layer, while an LPDA with the same outer geometry and substrate configuration but without OLRs was used as the reference. Laboratory measurements at five frequencies across the band show that the OLR-loaded antenna consistently provides higher gain. The average measured gain increased from 5.06 to 6.50 dBi, while at 2400 MHz it increased from 5.37 to 6.70 dBi. The measured (-10) dB bandwidth also increased from 1488 to 1550 MHz. In contrast, S 11 at 2400 MHz changed from (-23.65) to (-18.17) dB, indicating that the gain increase was not associated with improved input matching. Overall, the results show that an internal OLR layer can improve the measured gain without increasing the outer antenna dimensions. Differences between simulated and measured results, as well as the indoor radiation-test environment, are considered as limitations of the present study.
Source: E3S Web of Conferences
Language: English
Topic: Antenna Design and Analysis
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W7225782844