S.V. Dudarev1, S.N. Darovskikh2, N.V. Dudarev3, D.G. Fomin4

1-4 South Ural State University (national research university) (Chelyabinsk, Russia)

One of the pressing problems of horizontally polarized omnidirectional antennas is their narrow bandwidth. In this regard, for systems operating in different frequency ranges, it is necessary to develop new radiating elements. Currently, there are many omnidirectional printed antennas, which are an array of radiators located around the circumference, which are used as dipoles, frames, etc. These antennas operate in the same frequency range and have a narrow band. There are also multilayer printed antennas, some layers of which are not fed directly, but are excited by the electromagnetic field of the "active" layers. "Passive" layers contain elements in the form of closed and open frames, polygons of various shapes. The use of such structures in multilayer antennas makes it possible to slightly expand the operating frequency band or obtain new narrow ranges. In this regard, a study aimed at determining the structure of the elements of a "passive" antenna, which provides an extension of the frequency range in comparison with known samples, is relevant.

The purpose of this study is to substantiate the application for a multilayer printed antenna of a new structure of a "passive" layer in the form of a set of "arc-shaped" dipoles excited by the electromagnetic field of the improved Alford antenna. The use of such a "passive" structure ensures the formation of a new frequency range.

The article proposes a new omnidirectional dual-band multilayer printed antenna with horizontal polarization of the radiation field. The antenna consists of two printed circuit boards. The first board contains an improved Alford loop antenna, which consists of eight F-shaped sections, four on each side of the board. The second printed circuit board is fixed above the first and contains four pairs of "passive" dipoles of different sizes, located around the circumference. "Passive" dipoles are not fed directly, but are excited by the electromagnetic field created by the radiating elements of the first board. The printed circuit boards are separated by an air gap. Electrodynamic modeling of the antenna was carried out in the HFSS software package, the following characteristics were obtained: the reflection coefficient, the antenna directional patterns in the plane of the vector E and H. The frequency response of the reflection coefficient contains two ranges: 1.7-2.4 GHz and 4.1-4.88 GHz. Directional patterns in the plane of the vector E and H are given for the main and cross-polarization at the boundary and central frequencies of the first and second frequency ranges. The influence of the gap size on the characteristic of the reflection coefficient was investigated, it was revealed that the optimal value of the air gap between the boards is 3 mm or 0.045λ (for a frequency of 4.5 GHz). Therefore, dielectric rods regulating the gap are provided in the antenna design. The negative influence of the "passive" structure is a slight narrowing of the first frequency range from 39% to 36%. Also, the radiation pattern in the second frequency range has unevenness worse than in the first one.

The study showed the possibility of using the proposed omnidirectional multilayer printed antenna as an independent antenna or element of the antenna array of a base station of cellular communication of generations 2 G, 3 G, 4 G, 5 G. The antenna has a compact size and weight, which makes it possible to install it on small unmanned aerial vehicles. In this case, the antenna can be used to measure and control the characteristics of radio engineering systems and complexes.

Dudarev S.V., Darovskikh S.N., Dudarev N.V., Fomin D.G. Dual-band omnidirectional printed antenna with combined excitation.
Radiotekhnika. 2022. V. 86. № 3. P. 124−133. DOI: https://doi.org/10.18127/j00338486-202203-12 (In Russian)

1. Quan X. L., Li R. L., Wang J. Y., Cui, Y. H. Development of a broadband horizontally polarized omnidirectional planar antenna and its array for base stations. Progress in Electromagnetics Research. 2012. V. 128. P. 441-456.
2. Zhang H.-Y., Zhang F.-S., Zhang F., Li T., Li C. Bandwidth enhancement of a horizontally polarized omnidirectional antenna by adding parasitic strips. IEEE Antennas and Wireless Propagation Letters. 2017. V. 16. P. 880-883.
3. Wei K., Zhang Z., Feng Z. Design of a wideband horizontally polarized omnidirectional printed loop antenna. IEEE Antennas and Wireless Propagation Letters. 2012. V. 11. P. 49-52.
4. Borja A. L., Hall P. S., Liu Q., Iizuka H. Omnidirectional loop antenna with left-handed loading. IEEE Antennas and Wireless Propagation Letters. 2007. V. 6. P. 495-498.
5. Guo M., Qian R., Zhang Q., Guo L., Yang Z., Xu Z., Wang Z. High-gain antipodal Vivaldi antenna with metamaterial covers. IET Microwaves, Antennas and Propagation. 2019. V. 13. № 15. P. 2654-2660.
6. Kakhki M.B., Mantash M., Kesavan A., Tahseen M.M., Denidni T.A. Millimeter-Wave Beam-Tilting Vivaldi Antenna with Gain Enhancement Using Multilayer FSS. IEEE Antennas and Wireless Propagation Letters. 2018. V. 17. №. 12. P. 2279-2283.
7. Patel S.K., Shah K.H., Kosta Y.P. Multilayer liquid metamaterial radome design for performance enhancement of microstrip patch antenna. Microwave and Optical Technology Letters. 2018. V. 60. №. 3. P. 600-605.
8. Setia V., Sharma K.K., Kishen K.S. Triple-Band Metamaterial Inspired Microstrip Antenna using Split Ring Resonators for WLAN/WiMAX Applications. 2019 IEEE Indian Conference on Antennas and Propagation (InCAP). 2019.
9. Yu K., Li Y., Wang Y. Multi-band metamaterial-based microstrip antenna for WLAN and WiMax applications. 2017 International Applied Computational Electromagnetics Society (ACES) Symposium. 2017.
10. Jarboua I., Ammar N., Aguili T., Baudrand H. Radiation pattern and scattering parameter for multilayer cylindrical loop antenna using the iterative method WCIP. AEU - International Journal of Electronics and Communications. 2019. V. 101. P. 192-199.
11. Guo L., Tang M.-C., Li D. A low-profile dual-polarized multilayer parasitic patch array antenna with narrow air gap. Microwave and Optical Technology Letters. 2018. V. 60. № 8. P. 2022-2029.
12. Chaubey A.K., Gupta S., Kumar A. Parasitic multilayer micro strip patch antenna for 4.40 GHz C-Band application. 2nd International Conference on Micro-Electronics and Telecommunication Engineering. 2018. P. 271-276.
13. Liu T., Yang H., He Y., Lu J. Cylindrical ring dielectric loaded horizontally polarized omnidirectional antenna for wideband radiation. AEU - International Journal of Electronics and Communications. 2018. V. 90. P. 123-129.
14. Ahn C.-H., Oh S.-W., Chang K. A dual-frequency omnidirectional antenna for polarization diversity of MIMO and wireless communication applications. IEEE Antennas and Wireless Propagation Letters. 2009. V. 8. P. 966-969.
15. Kurushin A.A., Bankov S. E. Modelirovanie antenn i SVCH-struktur s pomoshch'yu HFSS. M.: Solon-Press. 2019. 280 s. (In Russian)
16. Bankov S.E., Kurushin A.A., Razevig V.D. Analiz i optimizaciya trekhmernyh SVCH-struktur s pomoshch'yu HFSS. M.: Solon-Press. 2005. 224 s. (In Russian)