Showing papers on "Coplanar waveguide published in 1969"

Coplanar Waveguide, a Surface Strip Transmission Line Suitable for Nonreciprocal Gyromagnetic Device Applications

Abstract: A coplanar waveguide consists of a strip of thin metallic film on the surface of a dielectric slab with two ground electrodes running adjacent and parallel to the strip. This novel transmission line readily lends itself to nonreciprocal magnetic device applications because of the built-in circularly polarized magnetic vector at the air-dielectric boundary between the conductors. Practical applications of the coplanar waveguide have been experimentally demonstrated by measurements on resonant isolators and differential phase shifters fabricated on low-loss dielectric substrates with high dielectric constants. Calculations have been made for the characteristic impedance, phase velocity, and ripper bound of attenuation of a transmission line whose electrodes are all on one side of a dielectric substrate. These calculations are in good agreement with preliminary experimental results. The coplanar configuration of the transmission system not only permits easy shunt connection of external elements in hybrid integrated circuits, but also adapts well to the fabrication of monolithic integrated systems. Low-loss dielectric substrates with high dielectric constants may be employed to reduce the longitudinal dimension of the integrated circuits because the characteristic impedance of the coplanar waveguide is relatively independent of the substrate thickness; this may be of vital importance for Iow-frequency integrated microwave systems.

Microwave communication system for moving land vehicle

Abstract: The microwave communication system, in its preferred form, includes a stationary waveguide through which microwave energy flows in surface waves in the fundamental mode. The waveguide preferably is a semicylindrical dielectric rod with a metallic conducting shield on the flat surface of the rod, and with the remainder of the rod unshielded. An antenna having the same general guide configuration is positioned near the waveguide to transmit and receive communications to and from the waveguide. The antenna either is stationary or is mounted on a vehicle such as a railroad car and positioned so as to always be near the waveguide. One form of antenna actually comprises a novel directional coupler, and another is a resonant antenna. In the waveguide fabrication method, the pattern of the lines of force of the electrical field in an unshielded waveguide of a given shape is determined, and a plane perpendicular to the lines is located. A waveguide is formed with the original shape but cut away along the perpendicular plane. Then a conductive shield is located at the resulting surface.