Low-Profile Broadband Planar Log-Periodic Dipole Array Antenna for IEMI Detection Application

A low-profile planar log-periodic dipole array (PLPDA) antenna is presented for broadband intentional electromagnetic interference (IEMI) sensing over 2-6 GHz. The design employs only six printed dipoles in a modified LPDA, combined with a conformal-loaded reflector and a planar horn-shaped director as a Yagi section. The synergistic combination of the LPDA and Yagi configurations preserves the broadband, frequency-independent behavior of the LPDA while achieving a compact profile. In contrast, conventional LPDAs typically require more than 13 dipoles to cover the same band with poorer gain flatness. The proposed antenna exhibits a fractional bandwidth of 100% with VSWR < 2 and a stable gain of 6.9 ± 0.8 dBi. RE102 testing confirms the proposed PLPDA performance and measurement reliability, demonstrating its effectiveness for wideband IEMI detection and system-level EMC applications.