A.S. Bulavchuk, A.S. Voloshin

Perspective task of modern networks and communication is the creation of compact and miniature microstrip antennas operating in two bands. In this paper, two band microstrip antenna with two carved C-shaped slots are investigated. This antenna consists of a metal resonator, dielectric substrate and metal shield. Transmission of electromagnetic energy through a coaxial-feed port connected via a through hole in the screen and the substrate to the resonator. The characteristics of the investigated microstrip antenna modeling in CST «Microwave Studio». Calculated antenna return loss indicates the possibility of the antenna operate in two frequency bands. The ability of the antenna operates in two bands associated with the antenna structure. Because currents are excited at a low-band frequency occur at the edges of C-shaped slots. And the currents excited at the high-band frequency occur between the slots. At the resonant frequencies are simulated radiation patterns, which indicates that the investigating antenna has a wide angle of signal receive or transmit. Also modeled polarization diagram, which show that at the two resonance frequencies polarization direction is not changed and there is in the plane of the microstrip resonator. In this paper the influence geometrical parameter of gap on the frequency position of the resonances are investigated. Modeling of antenna return loss showed that the variable parameter strongly influences to the position of the high-frequency resonance, rather than on the position of the low-frequency resonance. This is due to the fact that the currents excited by high-frequency resonance, occur between the cut slots, and the variable parameter affects the size of the gap. Consequently, this parameter changes a wavelength which is excited at high frequency resonance. The equal position of the polarization and the ability the frequency shift of resonance of investigated antenna, by changing only one geometrical parameter - is the main advantage of the antenna. Such an antenna can be used in communication systems which require the polarization stability.