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Kirt Blattenberger - RF Cafe Webmaster

Copyright: 1996 - 2024
    Kirt Blattenberger,


RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling 2 MB. Its primary purpose was to provide me with ready access to commonly needed formulas and reference material while performing my work as an RF system and circuit design engineer. The World Wide Web (Internet) was largely an unknown entity at the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps while typing up your telephone line, and a nice lady's voice announced "You've Got Mail" when a new message arrived...

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Videos for Engineers - Intel Seattle's Wireless Energy Project
Videos for Engineers

RF Cafe Videos for Engineers - Intel's Wireless Energy Transfer LabWireless energy transfer is a big deal these days. This video from Intel labs shows an Intel engineer demonstrating his setup for transferring energy from a primary coil to a secondary coil located a couple feet away. The fundamentals aren't rocket science; this is basically a loosely coupled transformer that relies on mutual coupling of magnetic fields to move power from one place to the other. The trick is making the system highly efficient with small coil sizes. Consider the challenge of merely transferring low power data via near field communications (NFC) with coils the size of a cell phone cover. Texas Instruments and other companies are rushing to provide development platforms for contactless charging systems that are expected to eventually replace the wall wart world of chargers.

Increasing use of wireless communications require more and more antennas to support their data transmission. Many situations have limited available real estate for antenna placement. For example, Navy ships normally use metallic antenna elements to transmit and receive VHF (Very High Frequency) signals. However, these protruding structures lead to sighting problems and take up valuable space onboard. Additionally, the height of the antennae cause the ships to be detected on radar scans. The typical Navy vessel currently houses 80 different antennae. With increasing antenna demand in many situations, smaller antennas are becoming more valuable to save precious surface real estate.

The Technology
SSC Pacific has developed a technology that uses the magnetic induction properties of sodium chloride (salt) in sea water to create a VHF antenna. Sea water is pumped from the ocean into a stream and the width and length of the stream determine the frequency capabilities. An 80-foot-high stream could transmit and receive from 2 to 400 MHz with a relatively small footprint. The Sea Water Antenna is capable of transmitting and receiving VHF signals and has been tested at a receiving range of over 30 miles. The antennae needs of a typical Navy vessel with 80 metallic antennas could theoretically be replaced with only 10 Sea Water Antennas of varying heights and streams to cover the same frequencies. The technology could potentially be used on land with salt-supplemented water, replacing large unsightly antenna towers with fountains. Another use could be as a solar- or battery-powered emergency antenna system for watercraft.

Key Benefits
  • System could decrease antenna footprint in situations where shipboard real estate is scarce by eliminating the need for metallic antenna structures
  • The height and width of the water stream could be adjusted to allow the Sea Water Antenna to transmit and receive many different frequencies
  • The Sea Water Antenna could be turned off when not in use, with no unsightly structure obscuring views, or even allowing ships to avoid radar detection
  • System could be used portably as an emergency antenna for watercraft, potentially powered by battery, solar panel or foot pump
Development Status

Patent Pending: Navy Case Number 84943: Electrolytic Fluid Antenna

Videos for Engineers - RF CafeThis archive links to the many video and audio files that have been featured on RF Cafe.

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