Design of a Printed Dipole Antenna by Using the Substrate-Integrated Double Line Technology

In this article, a novel printed dipole antenna is proposed with gain enhancement by using the newly emerging substrate-integrated double line (SIDL) technology for potential 5G millimeter-wave (mm-wave) applications. As a three-wire transmission line, the SIDL incorporates two parallel inner strips and one grounded outer conductor. The inner strip pair protrudes and is bent bilaterally to form the dipole’s arms. The outer conductor is stretched out and splits into four strips in a fourfold symmetry along the longitudinal axis to boost the gain. A bilateral slotline technology is used to couple the energy from the feed to the SIDL structure, providing a broadband transition. The shaped SIDL and the transition contribute to the proposed dipole element and then are expanded to a
$1\times 2$
array, both of which are designed and fabricated by using the standard printed circuit board (PCB) process. The measurement discloses that the element has an actual −10 dB impedance bandwidth from 33.5 to 47.4 GHz (34.4%@40.4 GHz) with a practical peak gain of 7.00 dBi, which for the array are 32.0–45.1 GHz (34.0%@38.6 GHz) and 8.88 dBi, respectively. Good agreement between the simulated and experimental results demonstrates the feasibility of SIDL’s utilization in designing the printed dipole antenna for high-gain and wideband mm-wave applications.