In this article, a novel dual-band omnidirectional antenna for WiFi applications is presented and investigated. The proposed antenna is mainly composed of two pairs of half-wavelength dipoles with different lengths. It is fed by a microstrip balun, which provides a good impedance matching for desired dual-band operation. The dimension of the proposed antenna is only 50 mm × 10 mm × 1 mm (0.4λ0 × 0.08λ0 × 0.008λ0, and λ0 is the wavelength of 2.4 GHz). The performance study of this dual-band omnidirectional antenna with different geometric parameters has been conducted. The final design is fabricated and measured, and the results exhibit a good impedance bandwidth of approximately 19.2% for |S11| ≤ -10 dB ranging from 2.24 to 2.70 GHz centered at 2.4 GHz, and over 17.4% for |S11| ≤ -10 dB ranging from 4.73 to 5.6 GHz centered at 5.0 GHz. This antenna also has a stable gain of 2.09~2.87 dBi and omnidirectional radiation patterns over the whole operating band. Dual-band coverage, stable omnidirectional radiation performance, simple structure, and miniaturized dimension make this antenna an excellent candidate for WiFi applications.
2. Zhang, B.-C., C. Jin, and Z.-X. Shen, "Low-profile broadband absorber based on multimode resistor-embedded metallic strips," IEEE Trans. Microw. Theory Techn., Vol. 1, 1-9, 2019.
3. Lai, J., B. Feng, Q. Zeng, and S. Su, "A dual-band dual-polarized omnidirectional antenna for 2G/3G/LTE indoor system applications ," 2018 IEEE International Conference on Signal Processing, Communications and Computing (ICSPCC), 2018.
4. Wen, H., Y. Qi, Z. Weng, F. Li, and J. Fan, "A multiband dual-polarized omnidirectional antenna for 2G/3G/LTE applications ," IEEE Antennas Wireless Propag. Lett., Vol. 17, No. 2, 180-183, 2018.
5. Guo, D., K. He, Y. Zhang, and M. Song, "A multiband dual-polarized omnidirectional sntenna for indoor wireless communication systems," IEEE Antennas Wireless Propag. Lett., Vol. 16, 290-293, 2017.
6. He, Y., K. Ma, N. Yan, and H. Zhang, "Dual band monopole antenna using dubstrate integrated suspended line technology for WLAN application ," IEEE Antennas Wireless Propag. Lett., Vol. 16, 2776-2779, 2017.
7. Liu, Y., X. Li, L. Yang, and Y. Liu, "A dual polarized dual band antenna with omnidirectional radiation patterns," IEEE Trans. Antennas Propag., Vol. 65, No. 8, 4259-4262, 2017.
8. Hu, P. F., Y. M. Pan, K. W. Leung, and X. Y. Zhang, "Wide-/dual-band omnidirectional filtering dielectric resonator antennas," IEEE Trans. Antennas Propag., Vol. 66, No. 5, 2622-2627, 2018.
9. Buckley, J. L., K. G. McCarthy, L. Loizou, B. O’Flynn, and C. O’Mathuna, "A dual-ISM-band antenna of small size using a spiral structure with parasitic element," IEEE Antennas Wireless Propag. Lett., Vol. 15, 630-633, 2016.
10. Shi, W., Z. Qian, and W. Ni, "Dual-band stacked annular slot/patch antenna for omnidirectional radiation," IEEE Antennas Wireless Propag. Lett., Vol. 15, 390-393, 2016.