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Ka-Band Power Amplifiers Improve Satellite Communication Quality

Published Date
Author Cadence PCB Solutions

Key Takeaways

  • RF power amplification is a significant challenge faced by Ka-band applications. 

  • The robustness and reliability attributes of GaN-based solid-state Ka-band power amplifiers are better than traveling wave tube amplifiers.

  • One of the added advantages of solid-state Ka-band power amplifiers is that they can be combined to ensure RF output power above hundreds of Watts. 

Ka-band power amplifier in satellite communication

There has been tremendous growth in technologies such as IoT, autonomous driving, 5G telecommunication systems, and satellite communication. In all these applications, selecting a higher frequency is preferred for improved speed, performance, bandwidth, connectivity, and throughput. With higher frequencies, dimensional reduction is achieved in antennas and ground segment systems.

The Ka-band is one of the frequency bands extensively used for these applications. In a Ka-band frequency-supported system, Ka-band power amplification is inevitable. Ka-band power amplifiers convert low power signals to high power signals. They are typically employed in the transmit chain of a communication system to strengthen the signals before they are sent out through antennas. 

Utilizing the Ka-Band Frequency Spectrum

The demand for data connectivity is continuously growing. To achieve high-speed data connectivity, several technological developments are observed in fixed wired networks, terrestrial wireless networks, and satellite communication. Most service operators utilize higher frequency bands for increased bandwidth, speed, connectivity, and throughput. The frequency band extensively in use for wireless data communication is the Ka-band frequency spectrum. The Ka-band frequency is allocated widely for internet access and 5G.

The growth of satellite communication and its applications in weather monitoring, military systems, telecommunication, aeronautical communication, maritime, and navigation services have propelled the expansion of the spectrum utilization into Ka-band frequencies. The Ka-band frequency spectrum offers 3.5 GHz bandwidth, which is more than 4 times that of other commonly used frequency bands. The Ka-band provides excellent uplink (earth-to-satellite) connectivity as well. Despite these advantages, there are a few challenges to be overcome in Ka-band satellite communication systems. 

Challenges in Ka-Band Satellite Communication Systems

The Ka-band is a key electromagnetic frequency band employed in stationary as well as mobile equipment. Ka-band frequency applications are not limited to airborne or marine systems, satellite getaways, and portable satellite devices. In Ka-band-based systems, signal power amplification is a hurdle to overcome.

RF power amplification poses a significant challenge in Ka-band applications. Ka-band satellite communication equipment is expected to transmit high power signals over a wide bandwidth of 3.5 GHz. Along with high power, linearity and stability are necessary characteristics to be obtained by the Ka-band power amplifier.

To attain high transmission data rates, modulation techniques such as Quadrature Phase Shift Keying (QPSK) are used in satellite communication. These advanced modulation techniques also require higher performance linear amplification in Ka-band communication systems.

Ka-Band Power Amplifiers

General Configuration

The RF amplification section of a typical Ka-band transmitter system generally includes an up-converter and power amplifier. The modulated input signal coming to the up-converter is of low power characteristics. As low-power signals are not suitable for transmission, they need to be amplified. The Ka-band power amplifier accepts the up-converter output and converts the low-power signal to a high-power signal. The high-power signal from the Ka-band power amplifier is transmitted via an antenna to the target destination.

Among communication system modules, the Ka-band power amplifier is a core element. The transmission signal quality of the transmitter is directly dependent on the linearity of the Ka-band power amplifier. In communication systems, the power consumed by the transmitter and receiver play a vital role in the SWaP requirements of the whole communication system. The efficiency of the Ka-band power amplifier is an influencing factor determining the power consumption of the transceiver, which is why the design of power amplifiers is crucial in Ka-band communication systems. As the output power of the Ka-band power amplifier increases, it is favorable to extend the distance of communication. Considering all these aspects, designing a high-performance Ka-band power amplifier is the key to attaining quality wireless communication. 

Ka-Band Power Amplifiers: Shifting From Traveling Wave Tubes to Semiconductors

New advancements in Ka-band power amplifiers offer more balanced designs that match system requirements regardless of board impedance. There are custom and off-the-shelf solutions for Ka-band power amplification with high output power and other characteristics, such as high frequency, high linear gain, unconditional stability, regulated supply, and bias sequencing.

Traditional Ka-band satellite communication applications rely on a type of vacuum tube called a traveling wave tube amplifier for power amplification while maintaining efficiency. However, cutting-edge developments in manufacturing technology have changed the trend to solid-state devices such as GaAs power amplifiers and GaN power amplifiers.

Solid-state power amplifiers provide significant RF performance improvements. The robustness and reliability attributes of GaN-based solid-state Ka-band power amplifiers are better than that given by traveling wave tube amplifiers. One of the added advantages of solid-state Ka-band power amplifiers is that they can be combined to ensure RF output power above hundreds of Watts.

Ka-band power amplifiers must be designed with high linear gain, high efficiency, and stability to improve the quality of satellite communication. Cadence’s suite of software can help you design high-power Ka-band amplifiers with aggressive performance targets.

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