Several key products have been launched recently in the millimetre wave (mmWave) sector, specifically for the 60-GHz band. Many designers believe this unlicensed band holds the answer to unleashing very high-speed communications for digital devices in the home.
With the advent of high-definition (HD) video content on both TV and the Internet, the need for a wireless communications protocol that can transfer HD content at high speed is increasing. The 60-GHz band offers the opportunity to stream large files with high throughput—gigabits per second—but it does have its limitations.
Because of the high frequency, walls are a problem, and the technology needs line of sight to work. Supporters say the small range means multiple connections can be set up close to each other without interference, maximising frequncy reuse. This technology is therefore being adopted by AV equipment and laptops (ASUS launched the first 60-GHz enabled laptop in June 2010) for what is called in-room communication.
The Wireless Gigabit Alliance has been established to address the need for faster, wireless connectivity between computing, communications, and entertainment devices. This alliance has developed the WiGig specification for 60-GHz wireless communications.
WiGig supports data transmission rates up to 7 Gbits/s, which is more than 10 times faster than the highest 802.11n rate. It also supplements and extends the 802.11 media access control (MAC) layer and is backward compatible with the IEEE 802.11 standard. The IEEE 802.11ad task group has developed a draft standard for communication above 1 Gbit/s in the 60-GHz frequency band as well.
During June’s ICC 2011 conference in Kyoto, Japan, Panasonic revealed that it has developed a 60-GHz chipset that is optimised for mobile phones. This is an industry first. Because of the high energy consumption associated with the wide bandwidth, previous 60-GHz devices required too much power for implementation in smart phones and the like, which had to stick with 2.4 or 5 GHz.
Panasonic says its chipset, which comprises a 60-GHz transceiver and a baseband processor implemented in CMOS, enables lower than 1-W low-power multi-gigabit wireless communications. The chipset supports the WiGig specification and/or the IEEE802.11ad draft specification for 60 GHz.
Also, the chipset features the world’s lowest-noise signal generator (–95 dBc/Hz at 1-MHz offset frequency). Its forward error correction (FEC) decoding block has decreased in size by 30% compared to Panasonic’s conventional architectures, which the company says results in lower power consumption, because of the reduction in circuit complexity and operating frequency.
The chipset’s multiband voltage-controlled oscillator maintains excellent phase noise while covering the 9-GHz frequency bandwidth required by WiGig. When implemented in a suitable system, Panasonic claims the chipset will allow the transfer of a 30-minute compressed HD video within 10 seconds, which is 20 times faster than existing wireless local-area networks (LANs), according to Panasonic.
Another recent industry first in the 60-GHz space is Qualcomm Atheros and Wilocity’s collaboration on the AR9004TB, the first tri-band Wi-Fi chipset that integrates multi-gigabit 60-GHz Wi-Fi with seamless handoff to 2.4- or 5-GHz band Wi-Fi, via newly developed fast session transfer technology (Fig. 1).
Released at Computex in Taiwan at the end of May, the AR9004TB is being touted as the first chipset capable of supporting applications like I/O, video, and networking at the same speeds as the equivalent wired technology while maintaining whole home coverage and complete interoperability.
The AR9004TB supports the 2.4-, 5-, and 60-GHz bands and integrates 802.11n and WiGig into the same form factor. Its makers anticipate the chipset providing 802.11n Wi-Fi for the whole home along with WiGig for networked synchronisation of HD movies in seconds, as opposed to tens of minutes, plus I/O connection to USB3/SATA hard drives, instant “synch and go” between mobile platforms, streaming display to projectors/monitors, and high-performance wireless docking.
Also, the AR9004TB supports Bluetooth 4.0 and includes a new message-based coexistence interface for interference avoidance between Wi-Fi and Bluetooth. Sampling of the AR9004TB is expected to begin in summer 2011.
Developing systems based on these chipsets will require test equipment. As frequencies move into the millimetre range, making good spectrum and other signal measurements gets significantly tougher.
Agilent’s PXA signal analyser covers frequencies up to 50 GHz, and now with external mixing using a mixer such as the M1970V, it can cover up to 325 GHz and beyond (Fig. 2 and Fig. 3). The PXA is Agilent’s highest-performance mmWave analysis solution, and the company says it offers the industry’s most accurate, sensitive, and frequency-stable signal analysis.
Although the PXA is aimed at wireless communications, it’s also useful for other mmWave applications such as radar, surveillance, radio astronomy, and new imaging techniques used in the medical and air travel industries.
The PXA uses exclusive technologies like low noise path and noise floor extension (NFE) to remove distortion noise and further widen dynamic range. This allows it to measure the smallest of signals in the presence of very large signals, a task that has challenged test engineers and is critical to designing and testing leading-edge mmWave systems. Using the low noise path, the PXA has a displayed average noise level (DANL) of –138 dBm at 50 GHz. Using NFE, the PXA can further improve its DANL by approximately 6 dBm.
A recent launch in the test sector from Anritsu is the company’s ME7838A broadband vector network analyser (VNA), which provides single-sweep coverage from 70 kHz to 110 GHz with operation from 40 kHz to 125 GHz. The ME7838 also provides broadband characterisation of active and passive microwave and mmWave devices, including 60 GHz.
With the ME7838A design, mmWave modules can be mounted close to or directly on the wafer probe, making for easy calibration and less bulk. This advantage, as well as the fact that the ME7838A transitions at 54 GHz, gives the broadband VNA the widest dynamic range in its class—107 dB at 110 GHz and 92 dB at 125 GHz.