Technology and customer demand are intertwined in this and many other industries. Although it is often uncertain which of the two is driving the other, technology advancement is an essential part of the economic health of the high-frequency industry. As a review of some of the key RF/microwave technology areas will show, improvements in a wide range of device, component, and materials sciences are making tomorrow's products possible and today's products affordable.

Markets that are driving high-frequency technological enhancements include applications in commercial, military, industrial, medical, and automotive areas. Commercial communications, for example, continue to be driven by the growth of wireless devices and networks. And these networks must now provide more than just voice, as service providers whet their customers' appetites for multimedia services with package deals of voice, high-speed data, and even video over cellular telephones. The word "broadband" has come to mean more than just high-speed fixed Internet access as more and more service provides and network installers look to a future filled with mobile broadband wireless-access (BWA) communications devices.

Of course, the "holy grail" of broadband markets for the past decade has been the elusive "last mile" to the home. As copper-wired, optical, and wireless networks have expanded in terms of reach and broadband capabilities, "completion" of the network has hinged on delivering the widest communications pipe possible to each customer in order to support the greatest number of potential services. While AT&T, Verizon, and others have installed costly fiber-to-the-home (FTTH) last-mile solutions to provide their customers with extended services, many service providers have sought a broadband wireless alternative to that last mile, even exploring the use of millimeter-wave technology in the form of LMDS.

The final wireless solution, however, may lie in the form of WiMAX (www.wimax.com), an air interface originally conceived to provide printout fixed wireless communications at frequencies from 10 to 66 GHz. Although still experiencing the growing pains of standardization, the basis for a standard lies in the IEEE's 802.16 documentation and subsequent "a" through "e" work groups. The most recent work group (IEEE 802.16e) is establishing guidelines for the use of WiMAX air interfaces for mobile wireless applications employing orthogonal (OFDM) modulation.

Although the wireless-local-area network (WLAN) or Wi-Fi market was slow to gain momentum due to lack of standardization, it has prospered in spite of the number of variations on the original 802.11 standard proposal (such as IEEE 802.11a/b/g/n) and different operating frequencies. WLAN equipment suppliers have simply adapted as cellular suppliers have done, by developing multimode transceiver solutions to work across multiple standards.

Major Players
The WiMAX market appears poised for explosive growth, given that major forces in communications equipment, such as Intel Corp. (www.intel.com) and Motorola (www.motorola.com) view that market as critical to their future growth. (Those interested in a well-written white paper comparing WLAN (Wi-Fi) and WiMAX can download a free copy of "Understanding Wi-Fi and WiMAX as Metro-Access Solutions" from the Intel website.) And, in spite of the large amount of publicity on the potential of WiMAX for broadband services from these companies and those involved in the WiMAX Forum (www.wimaxforum.org), an industry organization devoted to the growth of WiMAX products and technology, WiMAX may be ready for testing under real world conditions. Trials are under way on equipment conforming to the initial, fixed version of WiMAX (the IEEE 802.16-2004 standard) with the mobile version of the specification (IEEE 802.16e) close to finalization.

Early applications for WiMAX equipment are expected to be as back-haul connections for cellular base stations, for WLAN base stations, as replacements for enterprise T1 lines, and as alternatives to digital-subscriber-line (DSL) high-speed Internet service in rural and developing areas. The lure of WiMAX-based services will certainly be enticing for many service providers, given that they will soon be able to add wireless services without the investment in a cellular or PCS license.

As a hint of what may be to come, last month Korean Telecom (KT) launched their Wi-Bro mobile broadband wireless network based on the coming IEEE 802.16e WiMAX standard. KT (a WiMAX Forum member) was lauded by WiMAX Forum President Ron Resnick at last month's Asia-Pacific Economic Cooperation's (APEC) annual event (Busan, Korea), "KT's Wi-Bro services provide an early glimpse to what is possible and that mobile WiMAX will be the technology to deliver personal broadband to consumers around the globe." During APEC, and with the support of a variety of new Wi-Bro handsets manufactured by Samsung, KT held live demonstrations of the new network and its services, including Wonder-Media (video), Wonder-message (SMS, MMS), Wonder-Phone (mobile VoIP), and Wonder-Tour (location-based services delivered to PDAs, tablet personal computers, and laptop computers).

Cellular Volleys
Of course, cellular operators will not sit idly waiting for WiMAX services to displace them. In order to enhance the reliability of Multimedia Broadcast/Multicast Service (MBMS) operation for third-generation (3G) cellular networks, the 3G Partnership Project (3GPP) has standardized on the use of patented DF Raptor forwarder (FEC) technology from Digital Fountain (www.digitalfountain.com). The DF Raptor technology supports both streaming and file downloading services for 3GPP 3G mobile telephones. The MBMS employs multicast and broadcast transmission for multimedia services so that multiple mobile devices can share common radio and network resources. The DF Raptor technology protects MBMS signals from packet loss, avoiding file and transmission degradation. According to Frederic Gabin, 3G Standards Project Leader at NEC, "Digital Fountain's FEC provides the best of both worlds: low bandwidth overhead, low processing requirements for client devices, and effective protection of MBMS file transfer and streaming services from packet loss over 3G wireless channels."

Cellular 3G designers also received a technological boost with the development of Peregrine Semiconductor's (www.peregrine-semi.com) HaRP^? technology enhancements to the company's UltraCMOS process. The process upgrade leads to improved intermodulation-distortion (IMD) performance in several switch products, ultimately resulting in greater dynamic range in cellular networks. The firm's PE42672 single-pole, seven throw (SP7T) and PE42660 single pole, six-throw (SP6T) switches for quad-band GSM and GSM/WCDMA handset applications benefit from the new technology with third-order intercept points of better than +70 dBm at cellular frequencies. The UltraCMOS technology involves the fabrication of silicon CMOS devices on an insulating sapphire substrate, which is capable of handling high power levels. The HaRP enhancement improves the linearity of the devices when operating at high power levels.