Dual-Band High-Gain Omnidirectional Slender Dipole Array With Small Cross Section for WLAN Application

Wireless local area network (WLAN) serves as a vital complement to mobile communication, typically requiring proper omnidirectional gain and beamwidth to balance propagation distance and vertical beam coverage. To suit router environment, antennas need to be designed with slender shapes and small cross sections. There is limited research on dual-band high-gain omnidirectional antennas, especially under the constraint of small cross sections, with scarce literature for reference. This work aims to address this gap by proposing a dual-band omnidirectional dipole and a power divider consisting of purely parallel strip lines. A dipole loaded with serpentine lines achieves both excellent matching conditions and omnidirectional radiation at WLAN 2.45-/5.5-GHz bands. A power divider with a modified topology consisting of parallel strip lines does not affect omnidirectionality. Four-unit array consisting of the reported dipole and divider is designed. The measured −10-dB impedance bandwidths are 200 MHz (8.4%, 2.29–2.49 GHz) and 520 MHz (9.1%, 5.48−>6 GHz), the peak gain ranges are 3.8–5.0 and 5.4–6.5 dBi, and out-of-roundness ranges are 1.1–2.1 and 1.0–2.4 dB. To the best of our knowledge, the proposed antenna achieves the smallest cross section compared with other dual-band high-gain omnidirectional antennas reported in literature, which is highly suitable for modern routers.