Wireless communication systems are becoming more and more important in our daily lives with the developments in semiconductor technology and signal processing methods. Examples of the most basic applications of modern wireless systems are high data rate communication (Telecommunications), remote sensing and distance/speed information acquisition (RADARs), global position information (GPS) acquisition and jammers. The RF spectrum is divided into bands to avoid interference between these systems, which rely on the use of radio frequency (RF) signals. According to the division made by NATO (North Atlantic Treaty Organization), the 1-2 GHz range is named as D band. In the segmentation made by the International Institute of Electrical and Electronics Engineers (IEEE), which is widely used today, the 1-2 GHz frequency band has been determined as the “L Band”. The location of the L band in the RF spectrum is given in Figure 1.
L band includes frequencies and channels used for cellular communications, global positioning services, air traffic radars, military radars, satellite communications, and radio astronomy. Frequency and channel sharing are determined by national and international authorized institutions. The L band part of the frequency sharing table published in the USA in 2016 by NTIA (US National Communications and Information Agency) is given in Figure 2.
One of the most basic requirements for realizing or interfering/suppressing many wireless systems in the L band is the power amplifier, which is also a part of the transmitter block. Power amplifiers are the units that increase the required signal to the desired output power value. Due to its structure, it is the component that consumes the most power and heats up in the device. For this reason, the operating parameters and size properties are determined according to the system in which it will be used. Since it is a power consuming and warming unit, its high efficiency is one of its important features.
TRON L band power amplifier amplifies signals in the L band band frequency range. The power amplifier has an output power of >10W, which is sufficient for most systems in the specified frequency range. The amplifier block diagram is given in Figure 3. The small signal gain of the power amplifier is > 47 dB. A triple riser is designed for this gain. These stages are the preamplifier, driver amplifier and power amplifier stages, respectively.
The power and gain required to drive the power amplifier stage are obtained with the preamplifier stage and the driver amplifier stage. The output power level is provided by the GaN material FET transistor on the last floor. The load pull simulation studies of the power amplifier stage designed using AWR, a computer aided design software, are given graphically in Figure 4. The system can be used with passive cooling.
Within the power amplifier, there are Gate driver and Drain switch control circuits for the power amplifier, which generate the necessary DC voltages for the amplifiers.
The cylindrical compact structure of the power amplifier is given in Figure 5. This compact structure with a diameter of 92mm and a height of 50mm provides advantageous use for many communication and mixing systems. The top has the cover to access the power amplifier part when needed. The system can be mounted on the surface where it will be used from cylindrical side surfaces. In addition, there are RF input – output connectors on the side surfaces that do not distort the cylindrical form and whose directions can be adjusted according to the system in which they will be used. The bottom surface is finned for passive cooling. Thus, no extra power is consumed for cooling and the system does not produce acoustic noise as there is no fan.
TRON L band power amplifier can be used at the transmitter floor of L-band wireless systems in the 1100 – 1650 MHz range and at the output stage of mixers to suppress global location services.