A new invention from the Faculty of Electrical Engineering, Universiti Teknologi MARA, uses ionised gas in fluorescent light tubes to transmit Internet wireless frequency signals throughout a building.
The invention employs an ionised gas enclosed in a tube as the
conducting element of an antenna. When the gas is electrically charged or ionised
to plasma, it becomes conductive and allows radio frequency signals to be
transmitted or received.
The invention comprises of a smart fluorescent antenna operating at a 2.4 GHz frequency band with a 3G/3.75G/4G router for Wi-Fi applications. A commercially available fluorescent tube, measuring 0.61 metres in length by 0.25 metres in diameter, is used as the plasma antenna. The gas inside the tube is a mixture of argon and mercury vapour in a 9:1 ratio. The tube is energised by a 240 V current, provided by a standard AC power supply. A glowing tube indicates that the gas inside the tube has been ionised to plasma and forms a plasma column, which becomes highly conductive in this state and can be used as an antenna.
A coupling sleeve designed to store the electrical charge and positioned at the lower end of the tube is used to connect the plasma tube to the router. When sufficiently ionised into a plasma state, the gas in the tube becomes conductive and allows radio frequency signals to be transmitted or received.
Measurements indicate that the plasma antenna yields a return loss over 10 dB in the 2.23 GHz to 2.58 GHz frequency band. The antenna's ability to operate as either a transmitter or receiver in this particular frequency band was verified through a series of wireless transmission experiments.
The performance of the antenna was measured using the Wi-Fi Received Signal Strength Indicator (RSSI) technique. The product was tested for a month in the Universiti Teknologi MARA's High Frequency Antenna Laboratory with results indicating that the signal was stronger and more stable compared to others signals.
The new antenna innovation is a low cost solution since the Wi-Fi signal can be transmitted into other rooms using a single router with a splitter cable. The fluorescent tube has dual functionality, reducing the cost of buying additional antennas. Commercial antennas are made from metal elements while this invention uses plasma element. Additionally, conventional antennas can only transmit and receive radio frequencies, while the fluorescent antenna not only transmits and receives radio frequency signals, but also can be used as a light emitting device.
Image Copyright: Faculty of Electrical Engineering, Universiti Teknologi MARA