A Week of GaN: 3 MMICs Target Ka-band, Reduced Area, and 5G Base Stations

June 28, 2021 by Adrian Gibbons

Qorvo, Microchip, MaxLinear, and Cree Wolfspeed have gone wide, electrically wide-band that is, with newly released GaN-based RF products for 5G and satellite communications.

The race to market with new technology is always a nail-biter. This week, three new GaN-based MMIC (monolithic microwave integrated circuits) have been released, targeting applications in 5G, defense, and satellite communications.

Here is a breakdown of the three new releases covered in this article: 

Not only do each of these releases include GaN for MMICs, Microchip and Cree Wolfspeed's new offerings claim to be GaN-on-SiC (gallium nitride on silicon carbide), specifically.


GaN on SiC vs Gan on SI comparison.

GaN-on-SiC vs Gan on SI comparison. Image used courtesy of Qorvo


Why is GaN-on-SiC technology at the forefront of 5G design today? What benefits does it possess over silicon-based substrates?


GaN-on-SiC Solving 5G Key Design Considerations? 

GaN technology has seen a rise in use in the past several years. GaN (SiC as well) technology has several advantages over silicon (Si) wafers or laterally diffused metal oxide semiconductors (LDMOS), making it ideal for 5G communications technology.

Specifically, SiC-based substrates provide superior thermal conductivity when compared to Si-based wafers, allowing for more power-dense packages. In addition, SiC provides a better lattice match with GaN reducing the rate of wafer defects.

Additionally, compared to LDMOS, GaN-on-SiC is said to provide a 20% reduction in package size, along with better efficiencies and the potential for future optimizations. In contrast, LDMOS is reaching the end of life.

Electrical performance may be the primary consideration when selecting a technology for your power amplification needs; however, Qorvo is investing in a novel solution using GaN-based technology in the S-band (3.1-3.5 GHz) and the X-band (9-11 GHz).


Beyond the Physics, There is SWaP-C

Size, weight, power, and cost (SWaP-C) is a popular marketing term for a set of significant engineering considerations in the design process that are as material constraints as physics-based.

The new GaN dual-band power amplifiers (PA), the QPA0007 and QPA0004, from Qorvo have taken this qualitative term and made it quantitative by potentially reducing the design area by 50% with the first commercially available reconfigurable GaN power amplifier for S/X-band radar applications. 


Comparison of the new configurable PAs vs. traditional PAs.

Comparison of the new configurable PAs vs. traditional PAs. Image used courtesy of Qorvo    


In addition to cutting the PA requirements in half, insertion loss is reduced by eliminating the switch associated with the traditional dual-band architecture, resulting in more power savings.


Brief specification overview of the new dual-use PAs.

Brief specification overview of the new dual-use PAs. Image used courtesy of Qorvo


Radar is only one potential RF application for GaN technology. 5G, commercial and defense satellite communications, and aerospace all benefit from the enhanced parameters available through GaN-on-SiC.


Teaming-up to Build a Better 5G Base Station

Cree Wolfspeed, a leader in GaN-on-SiC, and MaxLinear, a leading provider of RF solutions, have joined together to bring a new solution to the 5G base station, the WS1A3940-V1, and WS1A3640-V1.  

The MaxLinear transceivers, in conjunction with GaN-on-SiC technology, can support both the US 5G 280 MHz instantaneous bandwidth and the Asian/European 400 MHz bandwidth requirements. In addition, the Cree PAs are said to provide 50% efficiency at 39.5 dBm (~8 W). 

The solution is said to provide the ability to develop 64x64 or 32x32 MIMO systems while respecting SWaP concerns. 


Microchip Using GaN-on-SiC for the Ka-band

The final release, based on new GaN technology, is Microchip's Ka-band MMIC. The Ka-band, which defines the 27-31 GHz spectrum, is an up-and-coming electromagnetic spectrum allocation for 5G and ongoing satellite communications. 

The GMICP2731-10 is a GaN-on-SiC technology capable of delivering 10 W of saturated RF power with a 3.5 GHz bandwidth between 27.5 to 31 GHz. 


The application circuit for the GMICP2731-10 power amplifier

The application circuit for the GMICP2731-10 power amplifier. Image used courtesy of Microchip


This PA claims to be designed to support complex modulation schemes, like QAM-128, without distortion while providing the high power required to transmit video and data applications.

The MMIC boasts a 20% power-added efficiency (PAE), a 22 dB of small signal gain, and a 15 dB return loss. This return loss indicates that the MMIC could provide a good match to standard 50-ohm terminations. 

Additionally, Microchip included integrated DC-block capacitors to help reduce design complexity. 

Leon Gross, vice-president of Microchip's Discrete Products Group, says that GaN MMICs can achieve 30% lower SWaP when compared to similar gallium arsenide (GaA) solutions. 

With these three new releases using GaN, the prospect of GaN-based technology will likely continue onto the main stage over the next several years due to its favorable electrical characteristics. It seems that, regardless of individual industry players, the concept of SWaP is right at the forefront of GaN-on-SiC technology development. 



Interested in other GaN news? Find out more in the articles down below.

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