A Single-Fed Dual-Band Shared-Aperture End-Fire Antenna with Independent Band Control

This paper introduces a new single-port, dual-band end-fire antenna with a large frequency ratio supporting the application at both microwave (MW) and millimeter-wave (mmW) frequencies. The proposed antenna utilizes a mode-composite method achieved by incorporating a pair of L-shaped gaps into a T-shaped double-sided parallel strip line (DSPSL) to realize the dual-band function. Specifically, the evolved DSPSL functions as an electric dipole antenna at the MW band, while as a quasi-transmission line in TEM mode at the mmW band. To generate end-fire radiation at the mmW band, six stubs are periodically distributed along the quasi-transmission line to form a series-fed array. Owing to the merits of the mode-composite method, independent band control ability at the two bands is accomplished. A prototype was fabricated to verify the dual-band antenna design, the measured results show that the antenna has an impedance bandwidth of 6.5% and a peak gain of 5.2 dBi at the 3.5-GHz MW band, while an impedance bandwidth of 20.4% and a peak gain of 11.3 dBi at the 30-GHz mmW band. © 2025 IEEE.