Targeting 6G, “World’s First” Compact Amplifier IC Breaks 100 GHz

February 28, 2023 by Jake Hertz

A new high-frequency amplifier could play a significant role in future high-speed communication networks.

As the world becomes increasingly interconnected, the need for faster and more efficient communication networks continues to grow. In order to meet this demand, researchers are developing 5G and 6G to improve the speed and reliability of data transmission.

However, a major challenge in these advanced communication networks is ensuring reliable operation at higher frequency bands. To address this, the NTT Corporation recently announced a new amplifier IC module that offers high amplification performance all the way up to the 100 GHz bandwidth.


Photo of the baseband amplifier IC using InP HBT technology

Photo of the baseband amplifier IC using InP HBT technology. Image courtesy of NTT


In this piece, we’ll discuss the challenges of high-frequency amplification, its need in 5G and 6G networks, and how NTT's amplifier can help.


5G and 6G High-frequency Challenges

High-frequency bands improve data rates associated with next-generation communication technologies like 5G and 6G. For example, the 5G mmWave band operates at frequencies ranging from 24 GHz to 40 GHz, while the 6G mmWave band is expected to perform at frequencies ranging from 100 GHz to 1 THz.

While these higher frequencies bring faster communication data rates, they also bring about a number of significant design challenges.


High-frequency signals encounter transmission line effects along transmission mediums

High-frequency signals encounter transmission line effects along transmission mediums.


One of the major challenges with high frequencies in RF electronics is the presence of significant signal attenuation. As high-frequency signals propagate through the transmission medium, they encounter transmission line effects such as parasitics that result in energy loss and decreased signal amplitude. In a high-level model, the signal attenuation of an RF signal is directly proportional to the frequency, meaning that as frequencies get higher, signals experience greater attenuation. 

Additionally, as signals reach higher frequencies, distortion caused by non-linearities in the components has a significant impact on performance. For example, many RF amplifiers tend to tail off in gain at higher frequencies, resulting in distorted and non-linear amplifier outputs, which can lead to errors and inaccuracies in signal processing. 


The Solution: Amplification

In both instances, many of the high-frequency challenges of RF design can be solved through amplification.


Gain and bandwidth are often tradeoffs

Gain and bandwidth are often tradeoffs. Image courtesy of Petteri Aimonen


Amplification helps correct issues related to signal attenuation by increasing the amplitude of the signal. With respect to distortion, proper amplification can help to reduce distortion by ensuring that the signal is amplified linearly, preserving the integrity of the original signal.

However, a significant challenge in amplifying high-frequency signals is that amplifiers tend to have an inherent tradeoff between gain and bandwidth. This becomes particularly hard to achieve at higher frequencies where non-linearities and parasitics tend to result in greater loss and distortion. Ideally, RF designers would want both high gain and wide bandwidth, allowing for an even and uniform signal amplification across an entire frequency band. 


NTT Reveals 100 GHz Amplifier IC

Last week, NTT Corporation announced a high-frequency RF amplifier with a 100 GHz bandwidth.

The breakthrough was based on two major innovations: the use of InP-based heterojunction bipolar transistor (InP HBT) technology and advanced packaging mounting to incorporate a DC block function into the IC. With the combination of these technologies, NTT created a new amplifier IC module in a 1 mm x 1 mm package that achieves high gain at high frequencies as well as a relatively flat frequency response over 100 GHz.


The new amplifier from NTT

The new amplifier from NTT. Image used courtesy of NTT


While more details are yet to be unveiled, the researchers claim to have demonstrated that the amplifier IC module can amplify an ultra-wideband PAM-4 signal with a symbol rate of 112 gigabaud without distortion. The company hopes that its breakthrough achievement will play a vital role in future high-speed communication networks such as the Innovative and Optical Wireless Network (IOWN) and 6G mmWave.