MODELING THE ANTENNA INPUT IMPEDANCE BY THE METHOD OF MOMENTS

The paper presents a comparison of excitation source models when modeling antennas by the method of moments. By using a set of adjacent edges when specifying the impact, it is possible to obtain correct results when the computational grid of the antenna model is more frequent. This is shown on the example of a symmetric electric vibrator.

Asymmetrical dipole antenna based on a phase-correcting dielectric lens

Problem. Modern mobile robotic systems are increasingly used in various fields of human activity. More and more stringent requirements are imposed on them to ensure high throughput, broadband and reliability of data transmission and control channels at the maximum distance from the control center. And what I would like to note separately is the requirement to reduce the cost of such complexes as much as possible. Therefore, the development of technologically advanced, economically feasible antenna systems that provide an increase in the energy potential of the radio channel in the interval of the robotic complex - control point is one of the ways to solve this problem. Formulation of the problem. It is required to develop a mechanically strong, technological antenna, built on the basis of lens structures of various configurations, made of modern dielectric materials, characterized by reduced weight and size characteristics and cost price, which will increase the level of radiated electromagnetic energy in a wide frequency band. Purpose of the article. Present the developed model of an asymmetric dipole antenna and the results of a numerical experiment. Result. The antenna design is made on a metallized round substrate and is a polystyrene cylinder with a funnel-shaped hole, inside which there is an asymmetrical conical vibrator arm. The results of calculations showed that in the frequency band, which is used to organize direct broadband radio communication channels with robotic complexes, the gain varies within 5.5-9 dB, which is superior in this parameter to the commonly used whip antennas. The calculated standing wave ratio confirms the performance of the developed antenna model in a wide frequency band. The impedance response and the Smith-Smith diagram showed a preliminary calculated spread of the input impedance of the antenna from 30 to 95 ohms. Practical significance. The proposed antenna model ensures manufacturability, mechanical strength, and low cost. The full-azimuth radiation mode and increased gain make it possible to predict the possibility of using this antenna as part of the equipment for the data transmission channel and control of robotic complexes such as unmanned aerial vehicles.

Tri-fed SIW based self-triplexer antenna for X-band applications

In this letter, an efficient and electrically compact cavity-backed self-triplexing antenna using a substrate integrated waveguide (SIW) technique is proposed. The antenna model is nested with an inverted “T”-shaped cavity and convert the rectangular SIW cavity into the two quarter mode (QM) and a half mode cavity (HM) approximately; excited through a coax probe and two micro-strip feed line separately. The proposed model operates at three distinct frequencies at 9.37 GHz, 9.86 GHz, and 10.36 GHz used for X-band wireless and radar communication systems. The self-triplexing feature is obtained with the mode perturbation concept and adequate intrinsic isolation of >31 dB is observed among three input ports. The proposed antenna possesses a minimum frequency ratio, uni-directional radiation patterns with high gain, and better efficiency.

Analysis of Bandwidth and Working Frequency of Bi-circular Antenna

This paper discusses the analysis results of determining the bandwidth and working frequency of a bi-circular antenna design. The analysis was carried out using three approaches, namely the FDTD simulation method, the measurement method using a network analyzer on the fabrication results of the antenna design, and the method of applying the bi-polygonal antenna model to the bi-circular antenna design. The novelty in this research is the application of the bi-polygonal antenna model and the comparison of the results of determining the bandwidth and working frequency of a bi-circular antenna with these three methods. Based on the results of the analysis using these three methods, it was found that different bandwidth values and the same antenna working frequency value were 2.45 GHz. The modeling results give a narrow and symmetrical form of return loss vs. frequency curve, the simulation results give a wide and slightly symmetrical form of return loss vs. frequency curve, and the measurement results give a wide and asymmetrical shape of return loss vs. frequency curve.