Abstract: An arrangement for heating includes an antenna which has at least one convolution of conductor centered on an axis. The antenna is adapted for receiving electrical power for heating a surface. A noncontacting temperature sensor is centered on the axis of the antenna with its field of view directed along the axis.

Abstract: A hybrid uses stubs to provide 90 degrees of phase shift between output lines for feeding a circularly polarized antenna. Capacitive and inductive stubs have low and high characteristic impedances for broad bandwidth. The stubs can be located in the output lines for compactness, or in a T-section between an input line and the output lines, for compactness, to minimize undesired phase shift, and for ease of connection. The hybrid can include one quarter wave transformers having a characteristic impedance of geometric mean of the hybrid and antenna for improved axial ratio.

Abstract: A UHF broadcast antenna system uses circular waveguide for the run from the high-power final amplifier to the antenna. Undesired cross-polarization components are formed in the circular waveguide due to unavoidable tolerances. Correction of the cross-polarization components is accomplished by a correction apparatus for sampling the principal polarization-plane signal, and reinjecting the sample with controlled amplitude and phase into the circular waveguide in the plane of the cross-polarization component for cancelling the cross-polarization.

Abstract: An antenna for CP signals uses a reflector, such as a truncated pyramid. Feed tubes, which act as a balun extend from the pyramid. Four truncated square loops are coupled to the feed means. The truncation results in a smaller radome being used and hence smaller wind resistance. A feed strap has a capacitance hat for a better match.

Abstract: A non-contacting RF shielding means is provided to inhibit the flow of energy in a given frequency band through an interface area between two conductive surfaces. A series of stub-like members are provided which are open circuited at one end and connected to a common conductive member on the other end. A portion of the first conductive surface is spaced from the stubs such that a plurality of microstrip lines are formed. The open circuits at the one end of the stubs reflect back as low impedance paths between the first surface and the other end of each of the stubs. The common conductive member is coupled to the second conductive surface. The arrangement thus provides a plurality of low impedance paths between the first and second conductive surfaces in the given frequency band without direct physical contact between the two conductive surfaces.

Abstract: A VHF television receiving antenna arrangement includes a cabinet having a loop of electrically conductive material disposed on its top, back and sides, preferrably on the inside surfaces thereof. A gap in the loop defines first and second feed terminals to which circuitry for tuning the loop connects. The loop is tuned thereby over at least a portion of the television frequency bands, responsive to a control voltage. Signals from the tuning circuitry are coupled to a television receiver tuner by a transmission line. Such loops can also have capacitors connected across tuning gaps for making the directional response of the loop more uniform at relatively lower frequencies (e.g. VHF channels 2-6) or switching diodes connected across control gaps for changing the directional response of the loop at relatively higher frequencies (e.g. VHF channels 7-13).

Abstract: A single-turn loop antenna suitable for inclusion within the cabinet of a television receiver has at least one gap forming a pair of feed terminals. Circuitry connects to the feed terminals for tuning the antenna over at least a portion of the television frequency bands and for coupling signals from the feed terminals to a transmission line. The circuitry provides isolation so the tuning of the antenna by the tuning circuitry is unaffected by the impedance of the transmission line or its terminating impedance and variations thereof. The circuitry is affixed to the loop proximate to the feed terminals, and the transmission line is affixed to the periphery of the loop and departs therefrom at a neutral point located, for example, opposite to the gap.

Abstract: A simplified short backfire directional antenna provides both sum and error adiation patterns in the H-plane. Three parallel dipoles are mounted above a pan-type reflector, with a small metal reflector disc over the dipoles. The center dipole is excited to produce a sum pattern and the two end dipoles are excited out of phase to provide an error pattern with a broadside null in the H-plane. Alternatively, a hybrid circuit may be used with a pair of parallel dipoles to generate the desired patterns. Improved gain and resolution are achieved with a small antenna array.

Abstract: Four conductive loops are symmetrically disposed in generally a common plane. The loops are closely spaced from each other to be in the strong electromagnetic coupling region of each other. The loops are fed in phase rotation at their inboard portions to provide a broad band circularly polarized antenna.

Abstract: Input and output waveguides are each formed from an inner tubular conductor coaxially disposed within an outer tubular conductor. The proximal ends of the waveguides are coupled through relatively rotatable sleeves of a coupling assembly that maintains the waveguides coaxial with a central axis. The field strength of a wave at the distal end of the input waveguide defines two cycles of a sinusoid about the axis. The inner conductors each carry on their outer surface an equal number of evenly spaced ridges. The ridges in the input waveguide cause the field strength to be invariant at the proximal ends. The ridges in the output waveguide cause the field strength to define the two cycles of the sinusoid at the distal end of the output waveguide.