Библиографическое описание:Передатчики ближнепольных магнитных систем связи : научное издание / А. Н. Бабицкий [и др.]. - Текст : непосредственный // Успехи современной радиоэлектроники. - 2017. - № 12. - С. 111-115. - ISSN 2070-0784. Перевод заглавия: Transmitters of near-field magnetic communication systems
Аннотация:Исследованы резонансный и нерезонансный варианты построения передатчиков ближнепольных магнитных систем связи, которые могут быть использованы для передачи информации в сложных условиях: связь с подземными и подводными объектами; обмен информацией с объектами, находящимися в железобетонных конструкциях и подвалах зданий, а также в других случаях, когда широко распространенные системы связи с использованием электромагнитных волн неэффективны. Рассмотрены варианты построения передатчиков с непосредственным подключением усилителя мощности к передающей катушке и с подключением через согласующий трансформатор. Приведены преимущества и недостатки представленных вариантов построения передатчиков, показаны возможности их практического использования.
Near-field magnetic communication systems are widely used for data transmission in difficult environment, when widespread electromagnetic-based communication systems are not effective. For example, near-field magnetic communication systems can be used for data exchange between underwater and underground objects; for communications with objects in basements and in reinforced concrete constructions; for secretive system operation, because near-field magnetic systems work only at short distances and cannot be fixed outside the system operation range. The distinctive feature of near-field magnetic links is a high signal attenuation on a propagation path. The signal power is decreased as a sixth power of a distance. It is necessary to increase a magnetic moment of a transmitter coil in order to extend the communication distance. The magnetic moment is calculated as M = NIS, where M - magnetic moment, A⋅m2; N - number of coil turns; S - coil area, m2. It is necessary to increase number of turns and current in the coil when loop area is limited. But the coil impedance growths with a square of turns and increasing of power amplifier supply voltage is necessary in order to keep current value in the transmitter coil. A voltage resonance can be used for increasing voltage on the transmitter coil, but a frequency bandwidth in this case is decreased. It is possible to keep the frequency bandwidth in the non-resonance transmitter coil with increasing the magnetic moment by reduction of coil turns and increasing coil current. That demands development of high power amplifiers for generating high currents in the transmitter coil. The transmitter coil can be connected to the power amplifier through a transformer. A primary winding of the transformer has more turns than a secondary winding and it is connected to the power amplifier. The secondary winding is connected to the transmitter coil. It allows the power amplifier to work with high voltages and low currents with high efficiency. The secondary winding and the transmitter coil can be made from a single high current multiconductor. The article shows several possible resonance and non-resonance constructions of near-field magnetic communication transmitters. These constructions can be used for developing of modern digital near-field magnetic communication systems. This work was supported by the Ministry of Education and Science of the Russian Federation, task no. 3.1031.2017/PCh.
