Recently, ultra-wideband (UWB) technology has attracted a lot of academic and industrial interests because it has the characteristics of extremely low transmission energy, very high bandwidth within short range, multipath immunity, and is extremely difficult to intercept. In addition, UWB technology has the advantages of low cost, low power, fading robustness, position location capability, and flexibility. There are many applications of this technology, such as WiGig, home networking, wireless universal serial bus (USB), wireless personal area network (WPAN), wireless body area network (WBAN), healthcare and medical imaging, and automotive radar. The burgeoning applications of UWB technology bring new challenges and opportunities for both the academia and the industry.

The main focus of this special issue is on the latest research and development in the areas of UWB components, circuits, systems, and applications in both microwave and millimeter wave bands. Original research articles as well as review articles are welcome. Potential topics include, but are not limited to:

• UWB passive components, such as UWB antennas and arrays, filter, power divider/combiner, quadrature coupler, balun, and phase shifter
• UWB circuit, such as LNA, VGA, PA, VCO, QVCO, downconversion mixer, upconversion mixer, pulse generator, signal generator, and UWB pulse-radar receiver/transmitter
• UWB systems, such as MIMO systems, 60 GHz short-range communication systems, and 24/77-GHz automotive radar system
• UWB applications, such as WiGig, home networking, wireless USB, WPAN, WBAN, healthcare and medical imaging, UWB communications over power lines, and security applications

Before submission authors should carefully read over the journal's Author Guidelines, which are located at http://www.hindawi.com/journals/jece/guidelines/. Prospective authors should submit an electronic copy of their complete manuscript through the journal Manuscript Tracking System at http://mts.hindawi.com/ according to the following timetable: