Направлена антена для контролю бездротових мереж передавання даних діапазону 5 ГГЦ

Abstract

В роботі наведено результати конструювання та досліджень активної конічної рупорної антени для роботи в діапазоні 5 ГГц, яка має здатність працювати у важких польових умовах з високим коефіцієнтом підсилення та низьким рівнем власних шумів. Recently, there has been an intensive development of wireless data networks in the 2.4 and 5 GHz ranges, or Wi-Fi. The popularity of these networks is mainly due to the transmission of multimedia information. Existing standards and data protocols for these networks ensure their smooth and high-performance operation in «ideal conditions». In fact, in cities and densely populated centers with a significant amount of such equipment as well as lack of backup channels, there is radio frequency interference. These interferences are caused by the impact of one piece of equipment on another when it is impossible to adjust by switching to backup channels. Due to the interference, the data transmission speed is reduced, and in some complex cases, the data transmission is stopped completely. This negative phenomenon especially affects the 5 GHz range, in which the signal range is less than that for the 2 GHz range. To assess the quality of wireless data transmission networks, the following characteristics are monitored: the average emission frequency and the emission bandwidth. When these characteristics go beyond the standard values, there are interferences detected by the radio frequency monitoring bodies. Monitoring is carried out monthly throughout the year by specialized measuring systems, which include spectrum analyzers and antennas. Existing antennas have the following disadvantages: instability of the amplification gain, significant noise radiation, low reliability of pushbutton switches and significant weight. To eliminate these shortcomings, the design of an active antenna with a conical horn, which has the ability to change the parameters of the antenna within the entire range of 5 GHz. The optimal parameters of the horn are calculated as well. To obtain high values of the amplification gain of the horn antenna and maintain them with high stability at temperatures from -20 to +45оС used a signal amplification unit on a high-frequency operational amplifier SZA5044Z with a thermostat on a powerful transistor. Additional stability of the electrical characteristics of the amplifier is provided by double stabilization of the supply voltage. Electronic antenna control increases the reliability of the antenna by using electronic switching instead of push-button. Electronic control also protects the antenna amplifier from overheating, changing the polarity of the battery and electromagnetic interference. Laboratory and field studies of the directional horn antenna showed high stability of its parameters, reliability and ergonomics. Additional stability of the electrical characteristics of the amplifier is provided by double stabilization of the supply voltage. Electronic antenna control increases the reliability of the antenna by using electronic switching instead of push-button one. Electronic control also protects the antenna amplifier from overheating, change of the battery polarity and electromagnetic interference. Laboratory and field studies of the beam horn antenna showed high stability of its parameters, reliability and ergonomics.