The Opportunities and Challenges of LTE Unlicensed in 5 GHz
David Witkowski, Executive Director, Wireless Communications Initiative
In 1998, the Federal Communications Commission established the Unlicensed National Information Infrastructure or U-NII 5 GHz bands. These are used primarily for Wi-Fi networks in homes, offices, hotels, airports, and other public spaces and also consumer devices. U-NII is also used by wireless Internet Service Providers, linking public safety radio sites, and for monitoring and critical infrastructure such as gas/oil pipelines.

MMD March 2014

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Band Reject Filter Series
Higher frequency band reject (notch) filters are designed to operate over the frequency range of .01 to 28 GHz. These filters are characterized by having the reverse properties of band pass filters and are offered in multiple topologies. Available in compact sizes.
RLC Electronics

SP6T RF Switch
JSW6-33DR+ is a medium power reflective SP6T RF switch, with reflective short on output ports in the off condition. Made using Silicon-on-Insulator process, it has very high IP3, a built-in CMOS driver and negative voltage generator.

Group Delay Equalized Bandpass Filter
Part number 2903 is a group delayed equalized elliptic type bandpass filter that has a typical 1 dB bandwidth of 94 MHz and a typical 60 dB bandwidth of 171 MHz. Insertion loss is <2 dB and group delay variation from 110 to 170 MHz is <3nsec.
KR Electronics

Absorptive Low Pass Filter
Model AF9350 is a UHF, low pass filter that covers the 10 to 500 MHz band and has an average power rating of 400W CW. It incurs a rejection of 45 dB minimum at the 750 to 3000 MHz band, and power rating of 25W CW from 501 to 5000 MHz.

LTE Band 14 Ceramic Duplexer
This high performance LTE ceramic duplexer was designed and built for use in public safety communication and commercial cellular applications. It operates in Band 14 and offers low insertion loss and high isolation to enable clear communications in the LTE network.
Networks International

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June 2014

GaAs: Meet the Silicon Pac-Man
By Ron Reedy, Co-Founder and CTO
Peregrine Semiconductor

Liam Devlin, CEO, Plextek RF Integration

Do you remember the yellow Pac-Man character? Gobbling up whatever crossed its path, Pac-Man navigated through a maze in search of the flashing “power dots” that would enable it to devour its attackers. In many ways, a voracious silicon Pac-Man has been and continues to thrive in the semiconductor space, consuming whatever lies in its path. Fueled by the market’s flashing “power dots” of high-volume demand, this silicon Pac-Man, aka CMOS, gobbles up its attackers—the other semiconductor technologies.

Back in the early 2000s, TEMIC Semiconductors added to its chips an image of a silicon Pac-Man eating gallium arsenide (GaAs). The company thought its silicon-germanium (SiGe) bipolar technology would be the answer. While I agree that a silicon Pac-Man will devour GaAs, a different silicon technology will be the victor: silicon-on-insulator (SOI). Nothing can stand in the way of Si CMOS on an RF (SOI) substrate. While GaAs has some advantages, such as a high-mobility and a semi-insulating substrate, it also has one key disadvantage—it is not silicon.

Time and time again when technologies attempt high volume, silicon comes in and wipes them out. High-volume markets are what drive the semiconductor industry to constantly innovate and improve. If a technology can’t drive volume, it will be unable to afford the fabs or the research needed for its next generation. In the early semiconductor days, silicon won, not because it was the easiest, but because it was the most flexible and adaptable.

Silicon has the ability to evolve better than any other technology, and it has two absolutely magnificent traits: it is monotonic, and it forms a native oxide. It is significantly easier to purify a monotonic, single atomic specie than to purify a combination of two elements and then, somehow, perfectly couple them together. All of the III-V semiconductors have this struggle—GaAs, indium phosphide (InP) and gallium nitride (GaN). The complexity of working with two different atomic species introduces an immense number of issues from purity and manufacturing to toxicity. With GaAs, this complexity is heightened with the rare earth element gallium and the toxic element arsenic. Silicon is one of the earth’s most common elements and forms a native oxide—silicon dioxide, otherwise known as beach sand. The benefits of silicon dioxide are numerous. It is a near-perfect insulator that can be deposited and grown thermally, and it is easily cleaned and etched. Also, with incredibly pure characteristics, it interfaces well with its silicon parent, enabling silicon dioxide on silicon and eliminating secondary electrical issues. Without silicon dioxide, neither the Si integrated circuit nor CMOS would be possible.

Beyond its natural benefits, silicon has many other advantages, including manufacturability, low cost, scalability, integration and a history of showing it will dominate whatever opportunity arises. Silicon has all but wiped out electronic technologies, from vacuum tubes to bipolar. Once a niche market reaches high volume, silicon finds a way to dominate. And remember, MOS and then CMOS, have driven Moore’s Law for 40 of the 50 years since Gordon Moore’s famous observation.

When I founded Peregrine in the early ’90s, I knew I needed to make silicon work in the RF world. I could predict the high-volume market was coming and saw the clear advantages of silicon. Unfortunately, the digital silicon at the time was unsuitable for RF applications. We recognized the path through SOI CMOS and knew that if we could fix the substrate, SOI CMOS would take over RF markets. Peregrine pioneered RF SOI and set down the groundbreaking path of enabling the substrate to do all the RF functions. While the industry thought we were crazy, we knew from day one that CMOS/SOI could do all the RF functions in a single technology and achieve true integration.

Fast forward 25 years, and the silicon RF CMOS/SOI Pac-Man is now consuming GaAs at the RF front end (RFFE). One can already see GaAs losing its grasp in high-volume applications. Over the last decade, multiple GaAs fabs have closed; RF SOI switches have replaced GaAs switches, and companies that had been solely focused on GaAs have started working with SOI. There has been a spirited debate in the industry on the demise of GaAs, but that debate has been finally settled. Silicon is driving GaAs out of high‑volume markets and returning the technology to its rightful place, a niche market. GaAs technology will survive, but as a dominant technology for niche markets, such as opto-electronics for fiber optics. I predict silicon will dominate the high-volume market, and GaN will complement it in the high-power market.

Nothing can stand in the way of RF SOI, thanks to its distinct advantages in flexibility, reliability, high ESD rating, superior settling time, lower power consumption and ease of reproducibility. In other words, it has all the benefits of CMOS and the ability to meet the stringent performance and cost requirements of the RFFE. The silicon Pac-Man will continue its dominance this time in RF markets.

Peregrine Semiconductor
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