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Dr. A. Kumar
Write for Microwaves & RF
8 results found for Dr. A. Kumar, displaying items 1 - 8

May 2010   [Components]
Antenna Assists MW Power Transmission
Power from space, by means of microwave power transmission using the sun as the energy source, has been a vision of many for decades. The power system would employ large solar- power satellites in geostationary earth orbit, and the system would consist of a solar energy collector to convert solar energy in direct current electricity, a DC-to-microwave converter, a large antenna array to beam the microwave power to the ground, and a receiving antenna on the...

October 2009   [Components]
Extract Petroleum With Microwaves
Petroleum can be extracted from tar sand and oil shale given an appropriate microwave applicator. These two materials are abundant on the North American continent and represent large reserves of low-viscosity crude petroleum. Microwave technology may provide a relatively cost-effective means of extracting the crude petroleum from these deposits of tar sand and oil shale. The most commercially accepted method of in situ extraction of...

January 2007   [Systems & Subsystems]
Electronically Steerable Antenna Cuts Low Profile
Two-way mobile communications require tunable antennas for best performance. But mechanically tuned antennas lack the tuning speed and reliability demanded of security, public safety, and first-responder teams. Fortunately, high-frequency innovator AK Electromagnetique, Inc. (Les Coteaux, Quebec, Canada) has developed a low-profile antenna system that can scan electronically in both azimuth and elevation angles. The innovative antenna system [...

September 2006   [Components]
Monopole Arrays Are Electronically Steerable
Electronically steerable antennas can provide beam scanning in azimthal and elevation planes without moving parts, adding to their reliability under severe weather conditions. Such an antenna has been developed based on a monopole center feed, an eight-monopole main ring, and 16 monopoles in two parasitic rings. The monopoles are embedded in dielectric to achieve a size reduction. The parasitic elements are connected to a controller circuit via a PIN diode and...

July 2005   [Components]
Microstrip Antennas Guide Satellite Data Transmissions
Satellite communications, such as the link provided by the Quicksat spacecraft for amateur radio operators at ultra-high frequency (UHF) and S-band, rely on high-performance antenna designs. Fortunately, a microstrip antenna design reported at S-band for remote sensing satellites can be adapted to provide the circularly polarized conical patterns required for effective data transmissions between the satellite and earth at both UHF and S-band frequencies. For medium-altitude,...

February 2005   [Test & Measurement]
Checker Reads Cellular Radiation
Long-term effects of electromagnetic (EM) radiation from cellular and Personal Communications Services (PCS) handsets are still unknown. Prudent practices include the use of measurement tools to detect unusually high levels of EM radiation from, for example, broken gaskets in a cellular handset package. Another safety measure is to measure the radiation levels from wireless handsets using a low-cost radiation checker as proposed in this article. This report will present the design, review...

March 2004   [Test & Measurement]
RCS Measurements Detect Power Lines
Power lines can be hazardous to low-flying aircraft. Fortunately, it may be possible to use microwave and millimeter-wave radar systems to accurately detect power lines, and prevent accidents. Even under conditions of fog, rain, and snow, it should...

December 2002   [Components]
Designing Antennas For Indoor Millimeter-Wave Use
Demand for bandwidth has been on the rise, pushing regulatory agencies such as the US Federal Communications Commission (FCC) to explore the use of millimeter-wave bands for commercial applications. Already, wireless local-area networks (WLANs) have...