Abstract: A method for forming a single cavity in a substrate, which may extend approximately the length of a device located on top of the substrate, and device produced thereby. The device has a length and a width, and may extend approximately the length of the substrate. After locating the device on the surface of the substrate, a first etchant is applied through openings on the surface of the substrate. Subsequently, a second etchant is applied through the same openings on the surface of the substrate. As a result, a single cavity is formed beneath the surface of the device, suspending the device and minimizing electrical coupling.

Abstract: A method is provided for the manufacture of a convective accelerometer and tilt sensor device using CMOS techniques. An integrated circuit chip is produced which includes a silicon substrate having an integrated circuit pattern thereon including a heater element located centrally of the substrate and at least first and second thermocouple elements located on the substrate on opposite sides of the heater element. Thereafter, portions of the substrate surrounding and beneath the heater and thermocouple elements are etched away to suspend the element on the substrate and thus to thermally isolate the elements from the substrate. The substrate is etched up to the cold thermocouple junction of the thermocouple elements so the cold junction remains on the substrate.

Abstract: A method for forming a single cavity in a substrate, which may extend approximately the length of a device located on top of the substrate, and device produced thereby. The device has a length and a width, and may extend approximately the length of the substrate. After locating the device on the surface of the substrate, a first etchant is applied through openings on the surface of the substrate. Subsequently, a second etchant is applied through the same openings on the surface of the substrate. As a result, a single cavity is formed beneath the surface of the device, suspending the device and minimizing electrical coupling.

Abstract: A compact and flat antenna that provides both Direct Broadcast Satellite and local off-air reception. The flat reflector is made of a composite material with multiple reflective radiating surfaces. The multi-stepped reflector combines both diffraction and refractive principals to collimate Radio Frequency signal waves to a short focal point. At the focal point a phase correcting splash plate and lens direct the RF signal through a low loss axis-fed circular waveguide and then to a low noise amplifier. This compact design reduces space, cost and over-all structure, which presents an aesthetically pleasing satellite communication antenna. The antenna aperture includes a VHF/UHF antenna element for reception of local and/or off-air broadcast TV signals eliminating the need and cost to install a separate antenna.

Abstract: A broadband microstrip antenna including two overlapping PC boards. A plurality of concentric spaced apart radiating rings and an upper ground plane layer are etched in the conductive upper surface of the upper PC board. An RF feedline network is etched in the conductive lower surface of the upper PC board. A continuous ground plane layer overlies the lower surface of the lower PC board. Plated through holes in the upper PC board connect a pair of 90.degree. spaced feed points on each of the rings to the feedline network. The feedline network is made of a plurality of conductive strips and matching stubs which are dimensioned and interconnected to permit the transmission/reception of circular polarized RF electromagnetic radiation while also matching the impedance of the rings to the impedance of a plurality of coaxial connectors mounted to the lower PC board.