: The diffraction of an acoustic surface wave by a wedge of fused quartz is analyzed. Theoretical results are given for wedge angles up to 180 deg, showing almost complete transmission of surface waves for a wedge angle of 90 deg. A new,... more
: The diffraction of an acoustic surface wave by a wedge of fused quartz is analyzed. Theoretical results are given for wedge angles up to 180 deg, showing almost complete transmission of surface waves for a wedge angle of 90 deg. A new, sensitive optical technique for measurement of acoustic wave transmission and standing wave ratio of surface waves provides experimental verification of the theory. This technique, using two coherent light beams focused on a fused quartz surface, is also useful for direct recording of attenuation, harmonic content and other propagation characteristics of acoustic surface waves. (Author)
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Research Interests:
Abstract : An analysis is made of a method for pulse-modulating a microwave signal so that the rise and fall times of the modulated pulse is on the order of 1 nsec. The components used are microwave switching diodes which have a switching... more
Abstract : An analysis is made of a method for pulse-modulating a microwave signal so that the rise and fall times of the modulated pulse is on the order of 1 nsec. The components used are microwave switching diodes which have a switching time much less than 1 nsec and a filter circuit which helps to reduce switching transients emerging from signal and source terminals of the switch. Analysis relates the suppression of the switching transients to the number of filter elements and switching times. (Author)
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In some applications of diode switches, such as in a switch- protected RADAR receiver, high speed switching is required in conjunction with a high degree of suppression of switching transients appearing at the rf terminals of the switch.... more
In some applications of diode switches, such as in a switch- protected RADAR receiver, high speed switching is required in conjunction with a high degree of suppression of switching transients appearing at the rf terminals of the switch. The minimum switching time of a series or shunt diode switch is derived to be 1.24/ f/sub o/, where f/sub o/ is the rf frequency being switched. The suppression of switching transients is derived, and it is found that suppression can be increased at the cost of increased filter complexity and switching time above the theoretical minimum. An example is presented utilizing the derived relationships.
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: The report describes the design, operation, and test results of a J-band absorption modulator-switch that has a power-handling capability of a few watts CW, > 40 kW peak, and a switching time of 25 dB) which is nearly independent of... more
: The report describes the design, operation, and test results of a J-band absorption modulator-switch that has a power-handling capability of a few watts CW, > 40 kW peak, and a switching time of 25 dB) which is nearly independent of magnetic control field in this OFF state, and a matched input impedance (VSWR < 1.5) for all values of applied control field. These electrical characteristics are nearly constant over a 20-percent bandwidth. Other characteristics of these microwave switches include small size (1-3/4 in. long), magnetic control field < 50 oersteds (Oe), operating temperatures exceeding 100C, and a potential switching-time of less than 1 microsec.