A.N. Ivanov – Engineer,
JSC «National technical physics and automation research institute»
A.S. Kukharenko – Ph.D.(Eng.), Leading Engineer,
JSC «National technical physics and automation research institute» E-mail: alexk.05@mail.ru
Monopole antennas are well-known constructions and at the moment they represent one of the most popular antenna element classes. Their construction simplicity and round shape of radiation pattern in azimuth direction allow their usage on must communication devices constructions. But these antenna elements also have some deficiencies. The main one is their dimensions, as their electricity length should be equal to a half ore a quarter of the wave length on the operating frequency. To decrease antenna element length engineers implement spiral-shape slow-wave systems in their constructions. Another deficiency of monopoles is their narrow operating band width, which becomes narrower in case of implementing a slow-wave system in to antenna element construction. The deficiency forces developers to use several antenna elements in constructions of communication devices. The aim of the paper is the description of multi band monopole antenna element construction and evaluation methodology. The methods will make possible the usage of such antenna elements for multi band communication devices.
The method of multi band monopole antenna element constructing is based on implementing of decoupling inductance in to its construction. The inductance acts as low-pass filter. Decoupling inductances divide antenna element on several parts, which together for quarter-wave monopoles on different operating frequencies. The operating frequencies are determined by values of decoupling inductances and their distance from antenna element base.
In the case on different operating frequencies different antenna element parts operate as radiating elements. On the highest operating frequency (the shortest wave length) only a part between antenna element base and first decoupling inductance radiate as signal on the frequency can’t propagate along the antenna element further than the first decoupling inductance. On the second operating frequency antenna element radiating length is prolonged up to the second decoupling inductance and so on.
The operating method is described in the paper with the help of presented antenna element equivalent schematic. Using the schematic a methodology of multi band monopole antenna element VSWR calculation is developed and presented in the paper. The methodology allows fast evaluation of basic antenna element construction parameters, such as radiating length, decoupling inductance position and value, number of turns and radius of slow-wave spiral elements.
The paper presents a detailed description of multi band monopole antenna element construction, the device equivalent schematic and method of the construction parameters evaluation and calculation. Results of practical measurements of dual-frequency and triple-frequency antenna elements are presented. Measured data are compared with data of antenna parameter evaluation.
Ivanov A.N., Kukharenko A.S. Method of calculation of helix monopole antenna resonant frequencies. Electromagnetic waves and electronic systems. 2020. V. 25. № 4. P. 20−27. DOI: 10.18127/j15604128-202004-03. (in Russian)
- Vychislitelnye metody v elektrodinamike. Pod red. R. Mitry. M.: Mir. 1977. 488 s. (in Russian)
- Yurtsev O.A., Runov A.V., Kazarin A.N. Spiralnye antenny. M.: Sovetskoe radio. 1974. 224 s. (in Russian)
- Sazonov D.M. Antenny i ustroistva SVCh. M.: Vysshaya shkola. 1988. 432 s. (in Russian)
- Fradin A.Z. Antenno-fidernye ustroistva. M.: Svyaz. 1977. 440 s. (in Russian)
- Glen J. Seward, Miller E. Multiband antenna system. US 6 107 972, H01Q1/00. Publ. 22.08.2000. Appl. No.: 08/929,142.
- Silin R.A., Sazonov V.P. Zamedlyayushchie sistemy. M.: Sovetskoe radio. 1966. 632 s. (in Russian)
- Shchelkunov S., Friis G. Antenny (Teoriya i praktika): Per. s angl.. Pod red. L.D. Bakhrakha. M.: Sovetskoe radio. 1955. 604 s. (in Russian)
- Allen W.N., Peroulis D. A Visual Approach to Investigating the Bandwidth of Transmission Lines with Non-Z0 Impedance. IEEE Antennas and Propagation Magazine. December 2013. V. 55. № 6. P. 220−235.