• Dielectric-Loaded Conformal Slot Antennas for Telemetry Applications

      Jones, H. S., Jr.; Harry Diamond Laboratories (International Foundation for Telemetering, 1971-09)
      The design and construction of a variety of slot antennas that conform to conical, ogival and cylindrical surfaces are described. These antennas are dielectric-loaded cavities or waveguide radiators with very thin metallic walls that are efficient and simple to fabricate. Some are fabricated from low-loss copperclad dielectric materials. Other designs involve the process of electroless copperplating over a dielectric substrate to form the cavity. Radiating slots are cut after the cavity configuration is formed. The feasibility of these antenna designs and the construction methods employed have been fully demonstrated. Many important advantages are derived from the use of the technique. It is highly suitable for the design of telemetry antennas in the L-band region. Antennas of this type lend themselves to flushmounting and can be easily designed to radiate through a dielectric window. Design parameters are easily controlled, thus allowing good overall electrical performance with consistent and reliable results for production quantities. Because they can be constricted to conform to the structures on which they are mounted, very good radiation pattern coverage is obtainable. Most models tested have good voltage standing-wave ratio characteristics and are capable of operating over at least a 101, bandwidth. Complete antenna systems with varied configurations have been designed in the frequency range from 1.0 to 2.5 GHz, yielding highly satisfactory results and at very low cost.
    • Preliminary Report on the Development of a Crystal-Controlled L-Band Artillery Telemetry Transmitter

      Richardson, J. F.; Harry Diamond Laboratories (International Foundation for Telemetering, 1971-09)
      Harry Diamond Laboratories (HDL) has a need for gun-rugged UHF telemetry transmitters for use in research and fuze testing programs. An in-house design program was started because of the specialized performance requirements for artillery electronics. This is the first status report on the effort. UHF transmitters are extremely sensitive to physical deformation because small dimensional changes produce reactance changes that can cause an appreciable change in frequency. Since ruggedized crystal-controlled oscillators limit the frequency shift to low levels and therefore permit early acquisition of artillery telemetry signals; a prototype transmitter was constructed to determine the degree of efficiency and compactness that could be obtained at L band. A compact 1510-MHz transmitter having an efficiency of 6 percent at an output power level of 160 mW is described. Physical dimensions are such that the transmitter can be readily potted in any artillery telemetry housing currently in use. Temperature compensation and gun ruggedization tests are currently in progress.